This file was created by the Typo3 extension sevenpack version 0.7.14 --- Timezone: CEST Creation date: 2013-05-24 Creation time: 11-31-51 --- Number of references 111 article SchindlerB2012 Current Biology 2013 1 23 2 177–182 Our subjective experience links covert visual and egocentric spatial attention seamlessly. However, the latter can extend beyond the visual field, covering all directions relative to our body. In contrast to visual representations [1, 2, 3 and 4], little is known about unseen egocentric representations in the healthy brain. Parietal cortex appears to be involved in both, because lesions in it can lead to deficits in visual attention, but also to a disorder of egocentric spatial awareness, known as hemispatial neglect [5 and 6]. Here, we used a novel virtual reality paradigm to probe our participants’ egocentric surrounding during fMRI recordings. We found that egocentric unseen space was represented by patterns of voxel activity in parietal cortex, independent of visual information. Intriguingly, the best decoding performances corresponded to brain areas associated with visual covert attention and reaching, as well as to lesion sites associated with spatial neglect. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science/article/pii/S0960982212014406 10.1016/j.cub.2012.11.060 aschindlerASchindler abartelsABartels article ZaretskayaAB2012 Journal of Neuroscience 2013 1 33 2 523-531 Grouping local elements into a holistic percept, also known as spatial binding, is crucial for meaningful perception. Previous studies have shown that neurons in early visual areas V1 and V2 can signal complex grouping-related information, such as illusory contours or object-border ownerships. However, relatively little is known about higher-level processes contributing to these signals and mediating global Gestalt perception. We used a novel bistable motion illusion that induced alternating and mutually exclusive vivid conscious experiences of either dynamic illusory contours forming a global Gestalt or moving ungrouped local elements while the visual stimulation remained the same. fMRI in healthy human volunteers revealed that activity fluctuations in two sites of the parietal cortex, the superior parietal lobe and the anterior intraparietal sulcus (aIPS), correlated specifically with the perception of the grouped illusory Gestalt as opposed to perception of ungrouped local elements. We then disturbed activity at these two sites in the same participants using transcranial magnetic stimulation (TMS). TMS over aIPS led to a selective shortening of the duration of the global Gestalt percept, with no effect on that of local elements. The results suggest that aIPS activity is directly involved in the process of spatial binding during effortless viewing in the healthy brain. Conscious perception of global Gestalt is therefore associated with aIPS function, similar to attention and perceptual selection. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.jneurosci.org/content/33/2/523.full.pdf+html 10.1523/​JNEUROSCI.2905-12.2013 nataliyaNZaretskaya SAnstis abartelsABartels article InceMBLP2011 Journal of Neuroscience Methods 2012 9 210 1 49–65 Mutual information is a principled non-linear measure of dependence between stochastic variables, which is widely used to study the selectivity of neural responses to external stimuli. Here we define and develop a set of novel statistical independence tests based on mutual information, which quantify the significance of neural selectivity to either single features or to multiple, potentially correlated stimulus features like those often present in naturalistic stimuli. If the values of different features are correlated during stimulus presentation, it is difficult to establish if one feature is genuinely encoded by the response, or if it instead appears to be encoded only as a side effect of its correlation with another genuinely represented feature. Our tests provide a way to disambiguate between these two possibilities. We use realistic simulations of neural responses tuned to one or more correlated stimulus features to investigate how limited sampling bias correction procedures affect the statistical power of such independence tests, and we characterize the regimes in which the distribution of information values under the null hypothesis can be approximated by simple distributions (Chi-square or Gaussian). Finally, we apply these tests to experimental data to determine the significance of tuning of the band limited power (BLP) of the gamma [30–100 Hz] frequency range of the primary visual cortical local field potential to multiple correlated features during presentation of naturalistic movies. We show that gamma BLP carries significant, genuine information about orientation, space contrast and time contrast, despite the strong correlations between these features. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science/article/pii/S0165027011006893 10.1016/j.jneumeth.2011.11.013 rinceRAAInce AMazzoni abartelsABartels nikosNKLogothetis stefanoSPanzeri article SchindlerHB2012 Cerebral Cortex 2012 9 Epub ahead The perception of a melody is invariant to the absolute properties of its constituting notes, but depends on the relation between them—the melody's relative pitch profile. In fact, a melody's “Gestalt” is recognized regardless of the instrument or key used to play it. Pitch processing in general is assumed to occur at the level of the auditory cortex. However, it is unknown whether early auditory regions are able to encode pitch sequences integrated over time (i.e., melodies) and whether the resulting representations are invariant to specific keys. Here, we presented participants different melodies composed of the same 4 harmonic pitches during functional magnetic resonance imaging recordings. Additionally, we played the same melodies transposed in different keys and on different instruments. We found that melodies were invariantly represented by their blood oxygen level–dependent activation patterns in primary and secondary auditory cortices across instruments, and also across keys. Our findings extend common hierarchical models of auditory processing by showing that melodies are encoded independent of absolute pitch and based on their relative pitch profile as early as the primary auditory cortex. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Scheffler http://cercor.oxfordjournals.org/content/early/2012/09/16/cercor.bhs289.full.pdf+html 10.1093/cercor/bhs289 aschindlerASchindler herdenerMHerdener abartelsABartels article Bartels2012 Neuropsychopharmacology 2012 7 37 8 1795–1796 Love, or in more functional–biological terms, social attachment or bonding, is the evolutionary key to the existence of species like humans: our babies’ survival depends entirely on parental care, which in turn provides the opportunity to transmit a vast amount of knowledge from one generation to the next. It is therefore no surprise that the brain's mechanisms that evolved to ensure parent–child bonding are powerful and under genetic control. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.nature.com/npp/journal/v37/n8/pdf/npp201271a.pdf 10.1038/npp.2012.71 abartelsABartels article ValverdeSalzmannBLS2012 Journal of Neuroscience 2012 6 32 23 7881-7894 Color vision is reserved to only few mammals, such as Old World monkeys and humans. Most Old World monkeys are trichromats. Among them, macaques were shown to exhibit functional domains of color-selectivity, in areas V1 and V2 of the visual cortex. Such color domains have not yet been shown in New World monkeys. In marmosets a sex-linked dichotomy results in dichromatic and trichromatic genotypes, rendering most male marmosets color-blind. Here we used trichromatic female marmosets to examine the intrinsic signal response in V1 and V2 to chromatic and achromatic stimuli, using optical imaging. To activate the subsystems individually, we used spatially homogeneous isoluminant color opponent (red/green, blue/yellow) and hue versus achromatic flicker (red/gray, green/gray, blue/gray, yellow/gray), as well as achromatic luminance flicker. In contrast to previous optical imaging studies in marmosets, we find clearly segregated color domains, similar to those seen in macaques. Red/green and red/gray flicker were found to be the appropriate stimulus for revealing color domains in single-condition maps. Blue/gray and blue/yellow flicker stimuli resulted in faint patch-patterns. A recently described multimodal vessel mapping approach allowed for an accurate alignment of the functional and anatomical datasets. Color domains were tightly colocalized with cytochrome oxidase blobs in V1 and with thin stripes in V2. Thus, our findings are in accord with 2-Deoxy-d-glucose studies performed in V1 of macaques and studies on color representation in V2. Our results suggest a similar organization of early cortical color processing in trichromats of both Old World and New World monkeys. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.jneurosci.org/content/32/23/7881.full.pdf+html 10.1523/​JNEUROSCI.4832-11.2012 valverdeMFValverde Salzmann abartelsABartels nikosNKLogothetis schuezASchüz article FischerLBB2011 Cerebral Cortex 2012 4 22 4 865-876 Motion processing regions apart from V5+/MT+ are still relatively poorly understood. Here, we used functional magnetic resonance imaging to perform a detailed functional analysis of the recently described cingulate sulcus visual area (CSv) in the dorsal posterior cingulate cortex. We used distinct types of visual motion stimuli to compare CSv with V5/MT and MST, including a visual pursuit paradigm. Both V5/MT and MST preferred 3D flow over 2D planar motion, responded less yet substantially to random motion, had a strong preference for contralateral versus ipsilateral stimulation, and responded nearly equally to contralateral and to full-field stimuli. In contrast, CSv had a pronounced preference to 2D planar motion over 3D flow, did not respond to random motion, had a weak and nonsignificant lateralization that was significantly smaller than that of MST, and strongly preferred full-field over contralateral stimuli. In addition, CSv had a better capability to integrate eye movements with retinal motion compared with V5/MT and MST. CSv thus differs from V5+/MT+ by its unique preference to full-field, coherent, and planar motion cues. These results place CSv in a good position to process visual cues related to self-induced motion, in particular those associated to eye or lateral head movements. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://cercor.oxfordjournals.org/content/22/4/865.full.pdf+html 10.1093/cercor/bhr154 efischerEFischer nikosNKLogothetis hhbHHBülthoff abartelsABartels article FischerBLB2012 Neuron 2012 3 73 6 1228-1240 Little is known about mechanisms mediating a stable perception of the world during pursuit eye movements. Here, we used fMRI to determine to what extent human motion-responsive areas integrate planar retinal motion with nonretinal eye movement signals in order to discard self-induced planar retinal motion and to respond to objective (“real”) motion. In contrast to other areas, V3A lacked responses to self-induced planar retinal motion but responded strongly to head-centered motion, even when retinally canceled by pursuit. This indicates a near-complete multimodal integration of visual with nonvisual planar motion signals in V3A. V3A could be mapped selectively and robustly in every single subject on this basis. V6 also reported head-centered planar motion, even when 3D flow was added to it, but was suppressed by retinal planar motion. These findings suggest a dominant contribution of human areas V3A and V6 to head-centered motion perception and to perceptual stability during eye movements. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://www.sciencedirect.com/science/article/pii/S0896627312001407 10.1016/j.neuron.2012.01.022 efischerEFischer hhbHHBülthoff nikosNKLogothetis abartelsABartels article CavusogluBYU2011 NeuroImage 2012 2 59 4 4044–4054 Cortical representations of the visual field are organized retinotopically, such that nearby neurons have receptive fields at nearby locations in the image. Many studies have used blood oxygenation level-dependent (BOLD) fMRI to non-invasively construct retinotopic maps in humans. The accuracy of the maps depends on the spatial extent of the metabolic and hemodynamic changes induced by the neural activity. Several studies using gradient-echo MRI at 1.5 T and 3 T showed that most of the BOLD signal originates from veins, which might lead to a spatial displacement from the actual site of neuronal activation, thus reducing the specificity of the functional localization. In contrast to BOLD signal, cerebral blood flow (CBF) as measured using arterial spin labeling (ASL) is less or not at all affected by remote draining veins, and therefore spatially and temporally more closely linked to the underlying neural activity. In the present study, we determined retinotopic maps in the human brain using CBF as well as using BOLD signal in order to compare their spatial relationship and the temporal delays of each imaging modality for visual areas V1, V2, V3, hV4 and V3AB. We tested the robustness and reproducibility of the maps across different sessions, calculated the overlap as well as signal delay times across visual areas. While area boundaries were relatively well preserved, we found systematic differences of response latencies between CBF and the BOLD signal between areas. In summary, CBF data obtained using ASL allows reliable retinotopic maps to be constructed; this approach is, therefore, suitable for studying visual areas especially in close proximity to large veins where the BOLD signal is spatially inaccurate. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler Department Logothetis http://www.sciencedirect.com/science/article/pii/S1053811911012201 10.1016/j.neuroimage.2011.10.056 mustafaMCavusoglu abartelsABartels barisBYesilyurt kuludagKUludag article StoewerGKBLDS2012 PLoS One 2012 1 7 1 1-13 fMRI experiments with awake non-human primates (NHP) have seen a surge of applications in recent years. However, the standard fMRI analysis tools designed for human experiments are not optimal for analysis of NHP fMRI data collected at high fields. There are several reasons for this, including the trial-based nature of NHP experiments, with inter-trial periods being of no interest, and segmentation artefacts and distortions that may result from field changes due to movement. We demonstrate an approach that allows us to address some of these issues consisting of the following steps: 1) Trial-based experimental design. 2) Careful control of subject movement. 3) Computer-assisted selection of trials devoid of artefacts and animal motion. 4) Nonrigid between-trial and rigid within-trial realignment of concatenated data from temporally separated trials and sessions. 5) Linear interpolation of inter-trial intervals and high-pass filtering of temporally continuous data 6) Removal of interpolated data and reconcatenation of datasets before statistical analysis with SPM. We have implemented a software toolbox, fMRI Sandbox (http://code.google.com/p/fmri-sandbox/), for semi-automated application of these processing steps that interfaces with SPM software. Here, we demonstrate that our methodology provides significant improvements for the analysis of awake monkey fMRI data acquired at high-field. The method may also be useful for clinical applications with subjects that are unwilling or unable to remain motionless for the whole duration of a functional scan. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029697 10.1371/journal.pone.0029697 e29697 stoewerSStoewer jozienJGoense georgeGAKeliris abartelsABartels nikosNKLogothetis JDuncan natashaNSigala article StoewerGKBLDS2011_2 Magnetic Resonance Imaging 2011 12 29 10 1390-1400 Functional magnetic resonance imaging (fMRI) experiments with awake nonhuman primates (NHPs) have recently seen a surge of applications. However, the standard fMRI analysis tools designed for human experiments are not optimal for NHP data collected at high fields. One major difference is the experimental setup. Although real head movement is impossible for NHPs, MRI image series often contain visible motion artifacts. Animal body movement results in image position changes and geometric distortions. Since conventional realignment methods are not appropriate to address such differences, algorithms tailored specifically for animal scanning become essential. We have implemented a series of high-field NHP specific methods in a software toolbox, fMRI Sandbox (http://kyb.tuebingen.mpg.de/~stoewer/), which allows us to use different realignment strategies. Here we demonstrate the effect of different realignment strategies on the analysis of awake-monkey fMRI data acquired at high field (7 T). We show that the advantage of using a nonstandard realignment algorithm depends on the amount of distortion in the dataset. While the benefits for less distorted datasets are minor, the improvement of statistical maps for heavily distorted datasets is significant. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science?_ob=MiamiImageURL&_cid=271222&_user=29041&_pii=S0730725X11001809&_check=y&_origin=&_coverDate=31-Dec-2011&view=c&wchp=dGLzVBA-zSkWb&md5=faaec51a67a063db4ac8f1979129b81b/1-s2.0-S0730725X11001809-main.pdf 10.1016/j.mri.2011.05.003 stoewerSStoewer jozienJGoense georgeGAKeliris abartelsABartels nikosNKLogothetis JDuncan natashaNSigala article 5283 Journal of Vision 2011 8 11 9:7 1-13 In binocular rivalry, the conscious percept alternates stochastically between two images shown to the two eyes. Both suppressed and dominant images form afterimages (AIs) whose strength depends on the perceptual state during induction. Counterintuitively, when these two AIs rival, the AI of the previously suppressed percept gains initial dominance, even when it is weaker. Here, we examined rivalry between afterimages, between real images, and between both to examine eye-based and binocular contributions to this effect. In all experiments, we found that for both AIs and real images, the suppressed percept consistently gained initial dominance following a long suppression period. Dominance reversals failed to occur following short suppression periods and depended on an abrupt change (removal) of the stimulus. With real images, results were replicated also when eye channels were exchanged during the abrupt change. The initial dominance of the weaker, previously suppressed percept is thus not due to its weaker contrast, to it being an afterimage, or to monocular adaptation effects as previously suggested. Instead, it is due to binocular, higher level effects that favor a perceptual switch after prolonged dominance. We discuss a plausible neural account for these findings in terms of neural interactions between binocular and eye-related stages. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.journalofvision.org/content/11/9/7.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.1167/11.9.7 abartelsABartels YVazquez-Zuniga aschindlerASchindler nikosNKLogothetis article BlaschkoSBLG2011 Pattern Recognition Letters 2011 8 32 11 1572-1583 Kernel canonical correlation analysis (KCCA) is a general technique for subspace learning that incorporates principal components analysis (PCA) and Fisher linear discriminant analysis (LDA) as special cases. By finding directions that maximize correlation, KCCA learns representations that are more closely tied to the underlying process that generates the data and can ignore high-variance noise directions. However, for data where acquisition in one or more modalities is expensive or otherwise limited, KCCA may suffer from small sample effects. We propose to use semi-supervised Laplacian regularization to utilize data that are present in only one modality. This approach is able to find highly correlated directions that also lie along the data manifold, resulting in a more robust estimate of correlated subspaces. Functional magnetic resonance imaging (fMRI) acquired data are naturally amenable to subspace techniques as data are well aligned. fMRI data of the human brain are a particularly interesting candidate. In this study we implemented various supervised and semi-supervised versions of KCCA on human fMRI data, with regression to single and multi-variate labels (corresponding to video content subjects viewed during the image acquisition). In each variate condition, the semi-supervised variants of KCCA performed better than the supervised variants, including a supervised variant with Laplacian regularization. We additionally analyze the weights learned by the regression in order to infer brain regions that are important to different types of visual processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf Department Logothetis http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V15-525YP08-1-1&_cdi=5665&_user=29041&_pii=S0167865511000481&_origin=&_coverDate=08%2F01%2F2011&_sk=999679988&view=c&wchp=dGLzVlb-zSkWb&md5=3fa7f7fa69d4474fd7a5a712a7266b8c&ie=/sdarticle.pdf http://www.robots.ox.ac.uk/~vgg/publications-new/Public/2011/Blaschko11a/blaschko11a.pdf 10.1016/j.patrec.2011.02.011 blaschkoMBBlaschko jsheltonJAShelton abartelsABartels chlCHLampert arthurAGretton article 6902 Current Biology 2010 12 20 23 2106-2111 Human brain imaging studies of bistable perceptual phenomena revealed that frontal and parietal areas are activated during perceptual switches between the two conflicting percepts [1,2,3]. However, these studies do not provide information about causality, i.e., whether activity reports a consequence or a cause of the perceptual change. Here we used functional magnetic resonance imaging to individually localize four parietal regions involved in perceptual switches during binocular rivalry in 15 subjects and subsequently disturbed their neural processing and that of a control site using 2 Hz repetitive transcranial magnetic stimulation (TMS) during binocular rivalry. We found that TMS over one of the sites, the right intraparietal sulcus (IPS), prolonged the periods of stable percepts. Additionally, the more lateralized the blood oxygen level-dependent signal was in IPS, the more lateralized the TMS effects were. Lateralization varied considerably across subjects, with a right-hemispheric bias. Control replay e xperiments rule out nonspecific effects of TMS on task performance, reaction times, or eye blinks. Our results thus demonstrate a causal, destabilizing, and individually lateralized effect of normal IPS function on perceptual continuity in rivalry. This is in accord with a role of IPS in perceptual selection, relating its role in rivalrous perception to that in attention [4,5,6]. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department MRZ http://www.sciencedirect.com/science/article/pii/S0960982210013618 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.cub.2010.10.046 nataliyaNZaretskaya thielscherAThielscher nikosNKLogothetis abartelsABartels article 6791 Journal of Vision 2010 10 10 12:3 1-14 In binocular rivalry, the visual percept alternates stochastically between two dichoptically presented stimuli. It is established that both processes related to the eye of origin and binocular, stimulus-related processes account for these fluctuations in conscious perception. Here we studied how their relative contributions vary over time. We applied brief disruptions to rivalry displays, concurrent with an optional eye swap, at varying time intervals after one stimulus became visible (dominant). We found that early in a dominance phase the dominant eye determined the percept by stabilizing its own contribution (regardless of the stimulus), with an additional yet weaker stabilizing contribution of the stimulus (regardless of the eye). Their stabilizing contributions declined in parallel with time so that late in a dominance phase the stimulus (and in some cases also the eye-based) contribution turned negative, favoring a perceptual (or ocular) switch. Our findings show that depending on the time, first proces ses related to the eye of origin and then those related to the stimulus can have a greater net influence on the stability of the conscious percept. Their co-varying change may be due to feedback from image- to eye-of-origin representations. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.journalofvision.org/content/10/12/3.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.1167/10.12.3 abartelsABartels nikosNKLogothetis article 6665 Magnetic Resonance Imaging 2010 10 28 8 1135-1142 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science/article/pii/S0730725X10001335 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.mri.2010.03.042 kevinKWhittingstall abartelsABartels vsinghVSingh soyoungSKwon nikosNKLogothetis article 6780 Journal of Vision 2010 8 10 10:27 1-15 When the two eyes are presented with dissimilar images, human observers report alternating percepts—a phenomenon coined binocular rivalry. These perceptual fluctuations reflect competition between the two visual inputs both at monocular and binocular processing stages. Here we investigated the influence of auditory stimulation on the temporal dynamics of binocular rivalry. In three psychophysics experiments, we investigated whether sounds that provide directionally congruent, incongruent, or non-motion information modulate the dominance periods of rivaling visual motion percepts. Visual stimuli were dichoptically presented random-dot kinematograms (RDKs) at different levels of motion coherence. The results show that directional motion sounds rather than auditory input per se influenced the temporal dynamics of binocular rivalry. In all experiments, motion sounds prolonged the dominance periods of the directionally congruent visual motion percept. In contrast, motion sounds abbreviated the suppression periods of the directionally congruent visual motion percepts only when they competed with directionally incongruent percepts. Therefore, analogous to visual contextual effects, auditory motion interacted primarily with consciously perceived visual input rather than visual input suppressed from awareness. Our findings suggest that auditory modulation of perceptual dominance times might be established in a top-down fashion by means of feedback mechanisms. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis Research Group Noppeney http://www.journalofvision.org/content/10/10/27.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.1167/10.10.27 conradVConrad abartelsABartels kleinermMKleiner unoppeUNoppeney article 6155 Cerebral Cortex 2010 8 20 8 1946-1954 The processing of color and form is largely segregated within the visual brain. But there is also evidence to suggest that these features are coded in combination early in visual processing. Here, we combined high-resolution functional magnetic resonance imaging (fMRI) together with multivariate pattern classification to examine where in the visual cortex specific color form "conjunctions" are represented. Human subjects viewed visual displays containing colored spiral patterns. The spiral patterns could be red or green, and oriented either clockwise or counterclockwise, leading to 4 possible stimulus configurations. Two additional displays combined 2 of the above single color-form pairings, leading to double conjunctions. We applied linear classifiers to voxel activation patterns obtained while subjects viewed such displays. Our findings not only show that color and form information is coded across retinotopically defined visual areas, but also that the 2 double-conjunction stimuli can be distinguished. The voxels most informative about conjunctions were distinct from those most informative about color or form alone. Our results indicate that conjunctions of form and color may be coded by separate functional units as early as primary visual cortex. The results of this study have implications for theories concerning the segregation and binding of color and form information. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://cercor.oxfordjournals.org/cgi/reprint/bhp265v1 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1093/cercor/bhp265 seymourKSeymour colincCWGClifford nikosNKLogothetis abartelsABartels article 5764 Current Biology 2009 4 19 7 R300-R302 Visual scenes are cluttered. Recent evidence suggests that areas as early as V1and V2 help making sense of the scene by segmenting them into distinct objects, separating foreground and background, and binding features. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6VRT-4W2F8TP-N-1&_cdi=6243&_user=29041&_orig=search&_coverDate=04%2F14%2F2009&_sk=999809992&view=c&wchp=dGLbVzz-zSkWb&md5=fd003d3f59a9a0eba0cc4f2f0cf67121&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.cub.2009.02.014 abartelsABartels article 5627 Current Biology 2009 2 19 3 177-183 Background. Colour and motion serve as the prime examples of segregated processing in the visual brain, giving rise to the question how colour-motion conjunctions are represented. This problem is also known as the ‘binding problem’. Results. Human volunteers viewed visual displays containing coloured dots rotating around the centre. The dots could be red or green, and rotate clockwise or counter-clockwise, leading to four possible stimulus displays. Superimposed pairs of such stimuli provided two additional displays, each containing both colours and both directions of motion, but differing in their feature-conjunctions. We applied multivariate classifiers to voxel activation patterns obtained whilst subjects viewed such displays. Our analyses confirm the presence of directional motion information across visual cortex, and provide evidence of hue coding in all early visual areas except V5/MT+. Within each cortical area, information on colour and motion appeared to be coded in distinct sets of voxels. Furthermore, our results demonstrate the explicit representation of feature conjunctions in primary visual cortex and beyond. Conclusions. The results show that conjunctions can be de-coded from spatial activation patterns already in V1, indicating an explicit coding of conjunctions at early stages of visual processing. Our findings raise the possibility that the solution of what has been taken as the prime example of the binding problem engages neural mechanisms as early as V1. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science/article/pii/S0960982209005442 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.cub.2008.12.050 seymourKSeymour colincCWGClifford nikosNKLogothetis abartelsABartels article 5282 Trends in Neurosciences 2008 9 31 9 444-453 fMRI is a tool to study brain function noninvasively that can reliably identify sites of neural involvement for a given task. However, to what extent can fMRI signals be related to measures obtained in electrophysiology? Can the blood-oxygen-level-dependent signal be interpreted as spatially pooled spiking activity? Here we combine knowledge from neurovascular coupling, functional imaging and neurophysiology to discuss whether fMRI has succeeded in demonstrating one of the most established functional properties in the visual brain, namely directional selectivity in the motion-processing region V5/MT+. We also discuss differences of fMRI and electrophysiology in their sensitivity to distinct physiological processes. We conclude that fMRI constitutes a complement, not a poor-resolution substitute, to invasive techniques, and that it deserves interpretations that acknowledge its stand as a separate signal. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science/article/pii/S0166223608001628 Biologische Kybernetik Max-Planck-Gesellschaft en doi:10.1016/j.tins.2008.06.004 abartelsABartels nikosNKLogothetis kmoutouKMoutoussis article 4494 Cerebral Cortex 2008 3 18 3 705-717 Visual changes in feature movies, like in real-live, can be partitioned into global flow due to self/camera motion, local/ differential flow due to object motion, and residuals, for example, due to illumination changes. We correlated these measures with brain responses of human volunteers viewing movies in an fMRI scanner. Early visual areas responded only to residual changes, thus lacking responses to equally large motion-induced changes, consistent with predictive coding. Motion activated V51 (MT1), V3A, medial posterior parietal cortex (mPPC) and, weakly, lateral occipital cortex (LOC). V51 responded to local/differential motion and depended on visual contrast, whereas mPPC responded to global flow spanning the whole visual field and was contrast independent. mPPC thus codes for flow compatible with unbiased heading estimation in natural scenes and for the comparison of visual flow with nonretinal, multimodal motion cues in it or downstream. mPPC was functionally connected to anterior portions of V51, whereas laterally neighboring putative homologue of lateral intraparietal area (LIP) connected with frontal eye fields. Our results demonstrate a progression of selectivity from local and contrast-dependent motion processing in V51 toward global and contrast-independent motion processing in mPPC. The function, connectivity, and anatomical neighborhood of mPPC imply several parallels to monkey ventral intraparietal area (VIP). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://cercor.oxfordjournals.org/cgi/reprint/18/3/705 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1093/cercor/bhm107 abartelsABartels SZeki nikosNKLogothetis article 3889 Vision Research 2006 7 46 14 2280-2286 The brain processes distinct attributes such as colour and motion in anatomically largely segregated systems. Moreover, these two attributes are perceived with different latencies. Here, we show that the time required to bind these two attributes differs too. In psychophysical experiments, we determined minimal presentation times required to perceptually pair spatially separate pairs of stimuli consisting of colour or motion. Binding two colours required longer presentation times than binding the directions of two moving stimuli. Cross-attribute binding between colour and motion took longer than within-attribute binding. This was so even when the relative perceptual delay between colour and motion was compensated for, which accelerated colour-motion binding. Moreover, stimuli could be discriminated but not bound at fast presentation rates. Our results thus show that spatial binding is an attribute-specific process and faster within the same than across different attributes. Furthermore, the time required to b ind attributes is independent of that required to process them, since colour is perceived before motion but requires longer time for binding. Finally, our results suggest that binding acts on attribute-specific neural representations of the stimuli at a late, perceptually explicit stage. These results lead us to conclude that spatial binding is separate from, and subsequent to, stimulus processing and that it is an attribute-dependent and post-conscious process. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sciencedirect.com/science/article/pii/S0042698905005997 Biologische Kybernetik Max-Planck-Gesellschaft en doi:10.1016/j.visres.2005.11.017 abartelsABartels SZeki article 4299 Sexuologie 2006 4 13 2-4 118-129 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://bibnet.org/vufind/Record/ccmed951893061 Biologische Kybernetik Max-Planck-Gesellschaft en abartelsABartels article 3887 Philosophical Transactions of the Royal Society of London B 2005 4 360 1456 733-750 We review here a new approach to mapping the human cerebral cortex into distinct subdivisions. Unlike cytoarchitecture or traditional functional imaging, it does not rely on specific anatomical markers or functional hypotheses. Instead, we propose that the unique activity time course (ATC) of each cortical subdivision, elicited during natural conditions, acts as a temporal fingerprint that can be used to segregate cortical subdivisions, map their spatial extent, and reveal their functional and potentially anatomical connectivity. We argue that since the modular organisation of the brain and its connectivity evolved and developed in natural conditions, these are optimal for revealing its organisation. We review the concepts, methodology and first results of this approach, relying on data obtained with functional magnetic resonance imaging (fMRI) when volunteers viewed traditional stimuli or a James Bond movie. Independent component analysis (ICA) was used to identify voxels belonging to distinct functional subdivisions, based on their differential spatio-temporal fingerprints. Many more regions could be segregated during natural viewing, demonstrating that the complexity of natural stimuli leads to more differential responses in more functional modules. We demonstrate that, in a single experiment, a multitude of distinct regions can be identified across the whole brain, even within the visual cortex, including areas V1, V4 and V5. This differentiation is based entirely on the differential ATCs of different areas during natural viewing. Distinct areas can therefore be identified without any a priori hypothesis about their function or spatial location. The areas we identified corresponded anatomically across subjects, and their ATCs showed highly area-specific inter-subject correlations. Furthermore, natural conditions led to a significant de-correlation of interregional ATCs compared to rest, indicating an increase in regional specificity during natural conditions. In contrast, the correlation between ATCs of distant regions of known substantial anatomical connections increased and reflected their known anatomical connectivity pattern. We demonstrate this using the example of the language network involving Broca's and Wernicke's area and homologous areas in the two hemispheres. In conclusion, this new approach to brain mapping may not only serve to identify novel functional subdivisions, but to reveal their connectivity as well. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://rstb.royalsocietypublishing.org/content/360/1456/733.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rstb.2005.1627 abartelsABartels SZeki article 3886 NeuroImage 2005 1 24 2 339-349 We describe here a new way of obtaining maps of connectivity in the human brain based on interregional correlations of blood oxygen level-dependent (BOLD) signal during natural viewing conditions. We propose that anatomical connections are reflected in BOLD signal correlations during natural brain dynamics. This may provide a powerful approach to chart connectivity, more so than that based on the ‘resting state’ of the human brain, and it may complement diffusion tensor imaging. Our approach relies on natural brain dynamics and is therefore experimentally unbiased and independent of hypothesis-driven, specialized stimuli. It has the advantage that natural viewing leads to considerably stronger cortical activity than rest, thus facilitating detection of weaker connections. To validate our technique, we used functional magnetic resonance imaging (fMRI) to record BOLD signal while volunteers freely viewed a movie that was interrupted by resting periods. We used independent component analysis (ICA) to segregate cortical areas before characterizing the dynamics of their BOLD signal during free viewing and rest. Natural viewing and rest each revealed highly specific correlation maps, which reflected known anatomical connections. Examples are homologous regions in visual and auditory cortices in the two hemispheres and the language network consisting of Wernicke's area, Broca's area, and a premotor region. Correlations between regions known to be directly connected were always substantially higher than between nonconnected regions. Furthermore, compared to rest, natural viewing specifically increased correlations between anatomically connected regions while it decreased correlations between nonconnected regions. Our findings therefore demonstrate that natural viewing conditions lead to particularly specific interregional correlations and thus provide a powerful environment to reveal anatomical connectivity in vivo. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/S1053811904005075 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/j.neuroimage.2004.08.044 abartelsABartels SZeki article 3888 NeuroImage 2004 5 22 1 419-433 A dominant tendency in cerebral studies has been the attempt to locate architecturally distinct parts of the cortex and assign special functions to each, through histological, clinical or hypothesis-based imaging experiments. Here we show that the cerebral cortex can also be subdivided into different components temporally, without any a priori hypotheses, based on the principle of functional independence. This states that distinct functional subdivisions have activity time courses (ATCs) that are, if not independent, at least characteristic to each when the brain is exposed to natural conditions. To approach a time-based anatomy experimentally, we recorded whole-brain activity using functional magnetic resonance imaging (fMRI) and analyzed the data with independent component analysis (ICA). Our results show that a multitude of cortical areas can be identified based purely on their characteristic ATCs during natural conditions. We demonstrate that a more "rich" stimulation (free viewing of a movie) leads to mo re areas being activated in a specific way than conventional stimuli, allowing for a more detailed dissection of the cortex into its subdivisions. We show that stimulus-driven functionally specialized areas can be identified by intersubject correlation even if their function is unknown. Chronoarchitectonic mapping thus opens the prospect of identifying previously unknown cortical subdivisions based on natural viewing conditions by exploiting the characteristic temporal "fingerprint" that is unique to each. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/S1053811904000333 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/j.neuroimage.2004.01.007 abartelsABartels SZeki article 3885 NeuroImage 2004 3 21 3 1155-1166 Romantic and maternal love are highly rewarding experiences. Both are linked to the perpetuation of the species and therefore have a closely linked biological function of crucial evolutionary importance. Yet almost nothing is known about their neural correlates in the human. We therefore used fMRI to measure brain activity in mothers while they viewed pictures of their own and of acquainted children, and of their best friend and of acquainted adults as additional controls. The activity specific to maternal attachment was compared to that associated to romantic love described in our earlier study and to the distribution of attachment-mediating neurohormones established by other studies. Both types of attachment activated regions specific to each, as well as overlapping regions in the brain&lsquo;s reward system that coincide with areas rich in oxytocin and vasopressin receptors. Both deactivated a common set of regions associated with negative emotions, social judgment and &lsquo;mentalizing&lsquo;, that is, the assessment of other people&lsquo;s intentions and emotions. We conclude that human attachment employs a push-pull mechanism that overcomes social distance by deactivating networks used for critical social assessment and negative emotions, while it bonds individuals through the involvement of the reward circuitry, explaining the power of love to motivate and exhilarate. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/S1053811903007237 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/j.neuroimage.2003.11.003 abartelsABartels SZeki article 3883 Human Brain Mapping 2004 2 21 2 75-85 Previous imaging studies have used mostly perceptually abstracted, idealized, or static stimuli to show segregation of function in the cerebral cortex. We wanted to learn whether functional segregation is maintained during more natural, complex, and dynamic conditions when many features have to be processed simultaneously, and identify regions whose activity correlates with the perception of specific features. To achieve this, we used functional magnetic resonance imaging (fMRI) to measure brain activity when human observers viewed freely dynamic natural scenes (a James Bond movie). The intensity with which they perceived different features (color, faces, language, and human bodies) was assessed psychometrically in separate sessions. In all subjects different features were perceived with a high degree of independence over time. We found that the perception of each feature correlated with activity in separate, specialized areas whose activity also varied independently. We conclude that even in natural conditions, when many features have to be processed simultaneously, functional specialization is preserved. Our method thus opens a new way of brain mapping, which allows the localization of a multitude of brain areas based on a single experiment using uncontrolled, natural stimuli. Furthermore, our results show that the intensity of activity in a specialized area is linearly correlated with the intensity of its perceptual experience. This leads us to suggest that each specialized area is directly responsible for the creation of a feature-specific conscious percept (a microconsciousness). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://onlinelibrary.wiley.com/doi/10.1002/hbm.10153/pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1002/hbm.10153 abartelsABartels SZeki article 3884 Cerebral Cortex 2003 2 13 2 189-202 This work investigates whether the brain assigns special cortical areas for the processing of kinetic contours. In human imaging experiments, we compared the brain activity produced in the so-called ‘kinetic occipital’ area (‘KO’) when humans perceive shapes generated from kinetic boundaries or from equiluminant colors. ‘KO’ was activated whenever subjects perceived shapes, no matter how they were derived; it is therefore not specialized for the processing of kinetic contours. The application of independent component analysis (ICA) to imaging data obtained when subjects viewed 22 min of an action movie showed that the time course of activity in ‘KO’ correlates better with activity in area V3 than with activity in two adjacent areas, V5 and LO. We thus consider ‘KO’ to be part of the V3 family of areas, and use the terminology of Smith et al. (J Neurosci 18:3816–3830, 1998), to refer to it as area V3B. Recordings from orientation-selective cells in the macaque V3 complex show that the great majority have the same orientational specificity when tested with oriented lines generated from kinetic stimuli or from luminance differences. We conclude that there is no present evidence for a visual area specialized for the processing of kinetic contours in the primate visual brain. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://cercor.oxfordjournals.org/content/13/2/189.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1093/cercor/13.2.189 SZeki RJPerry abartelsABartels article 3882 NeuroReport 2000 11 11 17 3829-3834 The neural correlates of many emotional states have been studied, most recently through the technique of fMRI. However, nothing is known about the neural substrates involved in evoking one of the most overwhelming of all affective states, that of romantic love, about which we report here. The activity in the brains of 17 subjects who were deeply in love was scanned using fMRI, while they viewed pictures of their partners, and compared with the activity produced by viewing pictures of three friends of similar age, sex and duration of friendship as their partners. The activity was restricted to foci in the medial insula and the anterior cingulate cortex and, subcortically, in the caudate nucleus and the putamen, all bilaterally. Deactivations were observed in the posterior cingulate gyrus and in the amygdala and were right-lateralized in the prefrontal, parietal and middle temporal cortices. The combination of these sites differs from those in previous studies of emotion, suggesting that a unique network of are as is responsible for evoking this affective state. This leads us to postulate that the principle of functional specialization in the cortex applies to affective states as well. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/bartels2000_NeuralBasisOfLove_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://journals.lww.com/neuroreport/pages/articleviewer.aspx?year=2000&issue=11270&article=00046&type=abstract Biologische Kybernetik Max-Planck-Gesellschaft abartelsABartels SZeki article 3881 European Journal of Neuroscience 2000 1 12 1 172-193 We have used the technique of functional magnetic resonance imaging (fMRI) and a variety of colour paradigms to activate the human brain regions selective for colour. We show here that the region defined previously [Lueck et al. (1989) Nature, 340, 386-389; Zeki et al. (1991) J. Neurosci., 11, 641-649; McKeefry &amp; Zeki (1997) Brain, 120, 2229-2242] as the human colour centre consists of two subdivisions, a posterior one, which we call V4 and an anterior one, which we refer to as V4alpha, the two together being part of the V4-complex. The posterior area is retinotopically organized while the anterior is not. We discuss our new findings in the context of previous studies of the cortical colour processing system in humans and monkeys. Our new insight into the organization of the colour centre in the human brain may also account for the variability in both severity and degree of recovery from lesions producing cerebral colour blindness (achromatopsia). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://onlinelibrary.wiley.com/doi/10.1046/j.1460-9568.2000.00905.x/pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1046/j.1460-9568.2000.00905.x abartelsABartels SZeki article 3878 Philosophical Transactions of the Royal Society of London B 1999 7 354 1387 1371-1382 We argue below that, at least in studying the visual brain, the old and simple methods of detailed clinical assessment and perimetric measurement still yield important insights into the organization of the visual brain as a whole, as well as the organization of the individual areas within it. To demonstrate our point, we rely especially on the motion and colour systems, emphasizing in particular how clinical observations predicted an important feature of the organization of the colour centre in the human brain. With the use of data from functional magnetic resonance imaging analysed by statistical parametric mapping and independent component analysis, we show that the colour centre is composed of two subdivisions, V4 and V4 alpha the two together constituting the V4 complex of the human brain. These two subdivisions are intimately linked anatomically and act cooperatively. The new evidence about the architecture of the colour centre might help to explain why the syndrome, cerebral achromatopsia, produced by l esions in it is so variable. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/bartels1999_PhilTransMeasure99_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692626/?tool=pmcentrez Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rstb.1999.0485 SZeki abartelsABartels article 3880 Neurocomputing 1999 6 26-27 293-298 Little is known about the constraints that neuromodulation places upon neural coding. We investigated the relationship between cholinergic modulation of spike timing and rate in a compartment model of a neocortical neuron. Our results suggest that cholinergic modulation of spike timing is directly related to the modulation of spike rate via the insertion of new spikes, and that spike timing is best preserved when the firing rate is low, i.e., when a rate code is ineffective (Thorpe et al., Nature 381 (6582) (1996) 520-522). We propose that neocortical neurons may use a spike timing and a rate code complementarily in different portions of their dynamic range. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/S0925231299000727 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/S0925-2312(99)00072-7 ACTang JWolfe abartelsABartels article 3879 Consciousness and Cognition 1999 6 8 2 225-259 The visual brain consists of several parallel, functionally specialized processing systems, each having several stages (nodes) which terminate their tasks at different times; consequently, simultaneously presented attributes are perceived at the same time if processed at the same node and at different times if processed by different nodes. Clinical evidence shows that these processing systems can act fairly autonomously. Damage restricted to one system compromises specifically the perception of the attribute that that system is specialized for; damage to a given node of a processing system that leaves earlier nodes intact results in a degraded perceptual capacity for the relevant attribute, which is directly related to the physiological capacities of the cells left intact by the damage. By contrast, a system that is spared when all others are damaged can function more or less normally. Moreover, internally created visual percepts—illusions, afterimages, imagery, and hallucinations—activate specifically the nodes specialized for the attribute perceived. Finally, anatomical evidence shows that there is no final integrator station in the brain, one which receives input from all visual areas; instead, each node has multiple outputs and no node is recipient only. Taken together, the above evidence leads us to propose that each node of a processing-perceptual system creates its own microconsciousness. We propose that, if any binding occurs to give us our integrated image of the visual world, it must be a binding between microconsciousnesses generated at different nodes. Since any two microconsciousnesses generated at any two nodes can be bound together, perceptual integration is not hierarchical, but parallel and postconscious. By contrast, the neural machinery conferring properties on those cells whose activity has a conscious correlate is hierarchical, and we refer to it as generative binding, to distinguish it from the binding that might occur between the microconsciousnesses. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/S1053810099903902 Biologische Kybernetik Max-Planck-Gesellschaft 10.1006/ccog.1999.0390 SZeki abartelsABartels article 3846 Proceedings of the Royal Society of London B 1998 12 265 1412 2327-2332 The theory of multistage integration is based on evidence that the visual brain consists of several parallel multistage processing systems, each specialized for a given attribute such as colour or motion. Each stage of a given system processes information at a distinct level of complexity. Our theory supposes that activity at any stage of a given multistage processing system is perceptually explicit--that is to say, it requires no further processing to generate a conscious experience. This activity can be integrated, or bound, with the perceptually explicit activity at any given stage of another or the same multistage processing system. Such binding is therefore not a process that generates a conscious experience, but rather one that brings different conscious experiences together. Many perceptual advantages result from such a flexible and dynamic integrative system. Conversely, there would be disadvantages to limiting perception and binding to hypothetical &lsquo;terminal&lsquo; stages of such processing systems or to hypothetical &lsquo;integrator&lsquo; areas. Although we formulate our hypothesis in terms of the visual brain, we believe it might form a general principle of brain functioning. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://rspb.royalsocietypublishing.org/content/265/1412/2327.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rspb.1998.0579 abartelsABartels SZeki article 3845 Philosophical Transactions of the Royal Society of London B 1998 11 353 1377 1911-1914 Anatomical and physiological evidence shows that the primate visual brain consists of many distributed processing systems, acting in parallel. Psychophysical studies show that the activity in each of the parallel systems reaches its perceptual end-point at a different time, thus leading to a perceptual asynchrony in vision. This, together with clinical and human imaging evidence, suggests strongly that the processing systems are also perceptual systems and that the different processing-perceptual systems can act more or less autonomously. Moreover, activity in each can have a conscious correlate without necessarily involving activity in other visual systems. This leads us to conclude not only that visual consciousness is itself modular, reflecting the basic modular organization of the visual brain, but that the binding of cellular activity in the processing-perceptual systems is more properly thought of as a binding of the consciousnesses generated by each of them. It is this binding that gives us our integrated image of the visual world. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/ZekiBartels1998_autonomy_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692424/ Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rstb.1998.0343 SZeki abartelsABartels article 3877 Nature Neuroscience 1998 9 1 5 335 Letters to Editor Nature Neuroscience 1, 335 (1998) doi:10.1038/1537 Has a new color area been discovered? S. Zeki, D.J. McKeefry, A. Bartels & R.S.J. Frackowiak Wellcome Department of Cognitive Neurology, Institute of Neurology, University College London, London WC1E 6BT UK To the editor − A recent paper in Nature Neuroscience1 claims to show "a previously undifferentiated cortical area that we call V8" in the human fusiform gyrus. This claim has given hopes to some2 that the cortical area responsible for the conscious perception of colors in humans has at last been found. However, the Talairach coordinates for this 'new' area "V8" (ref. 1) are identical to those that we had published for V4 (ref. 3). The authors have therefore not found a new area; instead they have rediscovered and tried to rename area V4. Furthermore, their report1 states, in reference to our paper3, that "a prior study also concluded that this human color-selective region included a representation of upper and lower visual fields". How, then, can they state that colors activate "area V8 but not V4" (ref. 1)? The answer is simple: it hinges on the use of the letter v, enabling one to write of V4 or V4v. To understand how a single letter can lead to such confusion, one has to retrace the history of the subject briefly. In 1995, Sereno and his colleagues, including Roger Tootell, co-author of ref. 1, reported the results of their mapping experiments in human visual cortex4. Many of the areas described had maps similar to ones found earlier in the macaque. Their map of what they supposed to be human V4 was not so straightforward. They distinguished a ventral V4v, located in the fusiform gyrus, from a dorsal V4d, located dorsolaterally, the two separated from each other by a relatively large expanse of cortex. V4v was clearly shown in the diagrams, but not V4d. This separation was unlike the V4 map in the monkey, where the two subdivisions, representing lower and upper visual fields respectively, are continuous with each other5. This made us suspicious, because the clinical evidence shows that lesions in the fusiform gyrus, where we had located V4 (Refs 3,6) can result in total hemi-achromatopsias7, 8 that include both upper and lower quadrants of the visual hemifield. We therefore undertook a mapping experiment3 and found, unlike the Sereno report4, that both quadrants are mapped within the color center (area V4) in the fusiform gyrus of each hemisphere. Human V4, like monkey V4, therefore contains a complete map of the visual hemifield in each hemisphere. It is this crucial finding that Hadjikhani et al.1 have now confirmed. Not surprisingly, the Talairach coordinates of their 'new' area are identical to those of V4 (plusminus26, -67, -9 for our V4 and plusminus33, -65, -14 for the 'new' color area) but differ significantly from the coordinates of the more posterior V4v, at plusminus32, -87, -16 (Fig. 1). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.nature.com/neuro/journal/v1/n5/pdf/nn0998_335a.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/1537 SZeki DJMcKeefry abartelsABartels RSJFrackowiak article 3844 Proceedings of the Royal Society of London B 1998 8 265 1405 1583-1585 We present below a simple hypothesis on what we believe is a characteristic of visual consciousness. It is derived from facts about the visual brain revealed in the past quarter of a century, but it relies most especially on psychophysical evidence which shows that different attributes of the visual scene are consciously perceived at different times. This temporal asynchrony in visual perception reveals, we believe, a plurality of visual consciousnesses that are asynchronous with respect to each other, reflecting the modular organization of the visual brain. We further hypothesize that when two attributes (e.g. colour and motion) are presented simultaneously, the activity of cells in a given processing system is sufficient to create a conscious experience of the corresponding attribute (e.g. colour), without the necessity for interaction with the activities of cells in other processing systems (e.g. motion). Thus, any binding of the activity of cells in different systems should be more properly thought of as a binding of the conscious experiences generated in each system. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://rspb.royalsocietypublishing.org/content/265/1405/1583.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rspb.1998.0475 abartelsABartels SZeki article 3843 Cerebral Cortex 1997 9 7 6 502-509 Neocortical neurons in vivo are spontaneously active and intracellular recordings have revealed strongly fluctuating membrane potentials arising from the irregular arrival of excitatory and inhibitory synaptic potentials. In addition to these rapid fluctuations, more slowly varying influences from diffuse activation of neuromodulatory systems alter the excitability of cortical neurons by modulating a variety of potassium conductances. In particular, acetylcholine, which effects learning and memory, reduces the slow alterhyperpolarization, which contributes to spike frequency adaptation. We used whole-cell patch-clamp recordings of pyramidal neurons in neocortical slices and computational simulations to show, first, that when fluctuating inputs were added to a constant current pulse, spike frequency adaptation was reduced as the amplitude of the fluctuations was increased. High-frequency, high-amplitude fluctuating inputs that resembled in vivo conditions exhibited only weak spike frequency adaptation. Second, bath application of carbachol, a cholinergic agonist, significantly increased the firing rate in response to a fluctuating input but minimally displaced the spike times by < 3 ms, comparable to the spike jitter observed when a visual stimulus is repeated under in vivo conditions. These results suggest that cholinergic modulation may preserve information encoded in precise spike timing, but not in interspike intervals, and that cholinergic mechanisms other than those involving adaptation may contribute significantly to cholinergic modulation of learning and memory. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://cercor.oxfordjournals.org/content/7/6/502.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1093/cercor/7.6.502 ACTang abartelsABartels TJSejnowski inproceedings 6064 Advances in Neural Information Processing Systems 22: 23rd Annual Conference on Neural Information Processing Systems 2009 2010 4 126-134 Resting state activity is brain activation that arises in the absence of any task, and is usually measured in awake subjects during prolonged fMRI scanning sessions where the only instruction given is to close the eyes and do nothing. It has been recognized in recent years that resting state activity is implicated in a wide variety of brain function. While certain networks of brain areas have different levels of activation at rest and during a task, there is nevertheless significant similarity between activations in the two cases. This suggests that recordings of resting state activity can be used as a source of unlabeled data to augment discriminative regression techniques in a semi-supervised setting. We evaluate this setting empirically yielding three main results: (i) regression tends to be improved by the use of Laplacian regularization even when no additional unlabeled data are available, (ii) resting state data seem to have a similar marginal distribution to that recorded during the execution of a visual processing task implying largely similar types of activation, and (iii) this source of information can be broadly exploited to improve the robustness of empirical inference in fMRI studies, an inherently data poor domain. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/NIPS2009-Blaschko_6064[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf http://nips.cc/Conferences/2009/ Bengio, Y. , D. Schuurmans, J. Lafferty, C. Williams, A. Culotta Curran

Red Hook, NY, USA

Advances in Neural Information Processing Systems 22 Biologische Kybernetik Max-Planck-Gesellschaft Vancouver, BC, Canada 23rd Annual Conference on Neural Information Processing Systems (NIPS 2009) en 978-1-615-67911-9 blaschkoMBlaschko jsheltonJShelton abartelsABartels inbook BartelsGL2011 2012 9 410-469 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://audition.ens.fr/brette/HandbookMeasurement/index.htm Brette, R. , A. Destexhe Cambridge University Press

Cambridge, UK

Handbook for Neural Activity Measurement 978-0-521-51622-8 abartelsABartels jozienJGoense nikosNKLogothetis inbook Bartels2010 2010 76-106 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.schattauer.de/shop/product_info.php/info/p503_.html/XTCsid/060bdefc431db8345d3b43ba8048bc29 Spitzer, M. , W. Bertram Schattauer

Stuttgart, Germany

Hirnforschung für Neu(ro)gierige: Braintertainment 2.0 978-3-7945-2736-6 abartelsABartels inbook 4298 2006 1 63-80 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Jouvent, R. , O. Lyon-Caen Editions Pil

Paris, France

Neuropsychiatrie ; 7 Les Emotions Biologische Kybernetik Max-Planck-Gesellschaft other 2913792197 RJouvent SZeki abartelsABartels inbook 4300 2004 201-229 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/book/9780122648410 Friston, K.J. , C.D. Frith, R.J.Dolan Academic Press

San Diego

2. ed. Human Brain Function Biologische Kybernetik Max-Planck-Gesellschaft 978-0-12-264841-0 abartelsABartels SZeki techreport 5901 2009 5 185 Kernel Canonical Correlation Analysis is a very general technique for subspace learning that incorporates PCA and LDA as special cases. Functional magnetic resonance imaging (fMRI) acquired data is naturally amenable to these techniques as data are well aligned. fMRI data of the human brain is a particularly interesting candidate. In this study we implemented various supervised and semi-supervised versions of KCCA on human fMRI data, with regression to single- and multi-variate labels (corresponding to video content subjects viewed during the image acquisition). In each variate condition, the semi-supervised variants of KCCA performed better than the supervised variants, including a supervised variant with Laplacian regularization. We additionally analyze the weights learned by the regression in order to infer brain regions that are important to different types of visual processing. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/MPIK-TR-185_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics, Tübingen, Germany en jsheltonJShelton blaschkoMBlaschko abartelsABartels poster BesserveBML2012 2012 10 42 507.20 Brain networks are characterized by strong recurrence, and widespread connectivity. As a consequence it is inherently difficult to tell apart local processing and interactions between structures. This is a major obstacle to the identification of a modular organization of the brain. However, complex network analysis enables to attack the problem from a different angle. Specifically, such analysis may consider directly the whole brain as a network and then characterize its topology. In this work, we use this framework to identify the polysynaptic topology of functional brain networks with a high spatial resolution. We first estimated network connectivity from fMRI signals by computing statistical dependency measures between pairs of voxels. Then, assuming that a restricted set of core regions relay information to the whole network, we developed a statistical test to characterize the structure of this high dimensional network using the concept of eigenvector centrality [1]. We applied these techniques to fMRI recordings in 6 humans during resting state and 4 monkeys during anesthesia. Eigenvector centrality measures based on correlation enabled us to identify a robust set of central areas that was similar in both species, involving cortical (precuneus, medial prefrontal cortex) and subcortical structures (hippocampus). Further graph theoretic analysis based on random walks allowed clustering these regions into robust groups with dedicated subnetworks of influence and to identify their hierarchical organization (clusters of central regions in human are shown in the figure below). In sum, centrality revealed a synthesis of the complex topology of functional networks in a consistent restricted set of core regions in monkey and human brains. Further work will investigate the temporal dynamics of these regions, and their influence on the activity of the whole network will be validated by experimental manipulation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Schölkopf http://www.sfn.org/am2012/ New Orleans, LA, USA 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012) besserveMBesserve abartelsABartels yusukeYMurayama nikosNKLogothetis poster SchindlerHB2012_2 2012 10 42 462.09 A melody consists of a temporal sequence of pitches. Its ‘Gestalt’ is invariant to absolute pitch but depends on the relation between pitches [[unable to display character: &#8211;]] the relative pitch profile. Consequently, a melody can be recognised regardless of the instrument used to play it and it even retains its identity after transposition to a different key, which involves a global change of all pitches in the melodic sequence. In contrast, a change in a melody’s temporal pitch order is usually accompanied with a change in its relative pitch profile and therefore also affects its melodic ‘Gestalt’. Pitch processing is assumed to occur in the auditory cortex. It is however still unknown whether early auditory regions are capable of integrating pitches over time and whether the resulting representations are invariant with respect to the key of their presentation. Here, we exposed participants to different melodies composed of the same four harmonic pitches during fMRI recordings. Additionally, we presented the same melodies transposed to different keys or played on different instruments. We found that melodies were invariantly represented by their BOLD activation patterns in primary and secondary auditory cortices across instruments, and also across keys. Our findings extend common hierarchical models of auditory processing by showing that melodies are encoded independent of absolute pitch and based on their relative pitch profile as early as primary auditory cortex. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Scheffler http://am2012.sfn.org/am2012/ New Orleans, LA, USA 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012) aschindlerASchindler herdenerMHerdener abartelsABartels poster ValverdeSalzmannBLS2012_2 2012 10 52 261.11 Color vision is reserved to only few mammals, such as Old World monkeys and humans. Most Old World monkeys are trichromats. Among them, macaques were shown to exhibit functional domains of color-selectivity, in areas V1 and V2 of the visual cortex. Such color domains have not yet been shown in New World monkeys. In marmosets a sex-linked dichotomy results in dichromatic and trichromatic genotypes, rendering most male marmosets color-blind. Here we used trichromatic female marmosets to examine the intrinsic signal response in V1 and V2 to chromatic and achromatic stimuli, using optical imaging. In order to activate the visual subsystems individually, we used spatially homogeneous isoluminant color opponent (red/green, blue/yellow) and hue versus achromatic flicker (red/gray, green/gray, blue/gray, yellow/gray), as well as achromatic luminance flicker. In contrast to previous optical imaging studies in marmosets, we find clearly segregated color domains, similar to those seen in macaques. Red/green and red/gray flicker were found to be the appropriate stimulus for revealing color domains in single condition maps (see figure). Blue/gray and blue/yellow flicker stimuli resulted in faint patch-patterns. A recently described multimodal vessel mapping approach allowed for an accurate alignment of the functional and anatomical datasets. Color domains were tightly colocalized with cytochrome oxidase blobs in V1 and with thin stripes in V2. Thus, our findings are in accord with 2-Deoxy-D-glucose studies performed in V1 of macaques and studies on color representation in V2. Our results suggest a similar organization of early cortical color processing in trichromats of both, Old World and New World monkeys. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/Neuroscience-2012-Valverde.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler Department Logothetis http://www.sfn.org/am2012/ New Orleans, LA, USA 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012) valverdeMFValverde Salzmann abartelsABartels nikosNKLogothetis schuezASchüz poster ZaretskayaB2012 2012 10 42 672.18 The processing of motion in the primate brain is distributed across multiple regions of the cerebral cortex. The two well-studied visual areas MT and MST have been linked to conscious perception and decision-making related to simple flow stimuli as well as to integration of component plaid motion into a coherently moving pattern. However, it is unclear whether processing and perception of other types of global motion, which require large-scale integration of the local signals, is related to activity of the same areas. In the current study we used fMRI to investigate neural responses to a bi-stable visual motion stimulus. The stimulus consisted of four pairs of dots, each pair coherently moving on a circular path. Perception alternated spontaneously between two states: local dot motion in each of the four quadrants of the visual field or global planar motion of two illusory squares spanning all four visual quadrants [1]. Importantly, these alternations were purely perceptual and involved no stimulus manipulation. We localized visual areas that are known to respond to visual movement (V3a, V6, V7, MT, MST, IPS1-4, and the recently described cingulate sulcus visual area (CSv) [2,3]) individually in each subject. We then investigated responses of these areas to global and local perceptual states of our subjects, while they viewed the bistable stimulus and reported their perception. We found that activity of two of the areas, CSv and IPS4, specifically correlated with global, but not the local perceptual states, while V6 showed a trend in the opposite direction. Interestingly, neither V5/MT, nor MST, nor any other motion-responsive region differentiated between global and local perceptual states. Our results suggest that CSv and IPS4 may be involved in the computation of global motion by large-scale integration of similar motion directions, or by spatial binding between distant loci in the visual field, respectively. Importantly, these results imply a certain 'blindness' of V5/MT and of MST to vivid changes in the conscious perception of large-scale motion stimuli. The perception of global, large-scale motion may therefore be mediated by higher-level motion-processing regions with larger receptive fields, such as by areas CSv and IPS4. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://am2012.sfn.org/am2012/ New Orleans, LA, USA 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012) nataliyaNZaretskaya abartelsABartels poster KwonWFB2012 2012 10 42 673.14 The responses of sensory neurons are noisy, and laboratory studies typically deal with this variability by averaging responses to many stimulus presentations. Recently, it has been observed that the noise signals carry important information about the brain activity, especially by observing the trial-to-trial noise correlation of spiking activity across populations of neurons (Ecker et al. 2010). The trial-to-trial fluctuations in the responses of pairs of neuron are affected by attention, and this has influence on behavior (Cohen et al. 2009, Mitchell et al. 2009). In particular, it was found that attention decreased the noise correlation of neural responses in V4, indicating a more efficient encoding or an increase of information content. Yet the results of these electrophysiology studies left it unclear whether such effects would also occur elsewhere in the cortex, and whether similar effects can be observed in the BOLD signal. In the present study we asked human participants to perform a difficult, attention-demanding task on a complex visual motion display during a prolonged period of time, alternated by equally long periods of visual stimulation without any task. Brain activity was recorded using fMRI. We then analyzed changes in the mean BOLD signal during both conditions, as well as the signal variance within the time-series of each condition. During attention, the BOLD signal variance decreased in several regions, including V5/MT, the temporal parietal junction, and in additional medial-frontal regions. Mean BOLD signal increased in early visual cortex, V5/MT, and in the parieto-frontal attention network. The results demonstrate firstly that the variance of BOLD activity can be altered by visual attention. Secondly they show that there is only a partial overlap between regions whose BOLD signal increases and those whose BOLD signal variance changes. This suggests that changes in variance and in net amplitude may reflect distinct brain processes related to attention. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://am2012.sfn.org/am2012/ New Orleans, LA, USA 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012) soyoungSKwon watanabeMWatanabe efischerEFischer abartelsABartels poster KuGLB2012 2012 10 42 263.22 fMRI has revealed a face processing network in the macaque brain that encompasses regions in the superior temporal sulcus (STS), the lateral and ventral temporal cortex, the medial temporal lobe and in the prefrontal cortex (Tsao and Livingstone 2008; Ku, Tolias et al. 2011). However, the functionality of each individual face-responsive patch is largely unknown. In humans fMRI evidence suggests that the middle STS is important for facial expression encoding, while the ventral temporal cortex is primarily involved in identity encoding (Haxby, Hoffman et al. 2002). This is consistent with single unit studies showing facial expression selective cells in the STS and identity encoding neurons in LTG in monkeys. However, there is no equivalent evidence indicating such a functional segregation in terms of BOLD responses to face stimuli. In order to examine whether there is a similar response pattern in monkeys and to further identify more candidate brain regions which might be also important in encoding these two aspects of faces, we scanned two awake and five anesthetized monkeys at 7Tesla. Using an adaptation paradigm we found that STS was sensitive to changing facial expressions independent of changing of identities in all awake and anesthetized monkeys. In brain regions not covered in the awake monkeys, the same contrast revealed that the medial orbital frontal cortex (area 47/12 ) of four anesthetized monkeys was also sensitive to changing facial expressions. In addition, we found that the anterior hippocampus of the two awake and three anesthetized monkeys was sensitive to changing identities. The results suggest differential selectivities for the encoding of facial expressions and of identities across a network of regions in the monkey. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sfn.org/am2012/ New Orleans, LA, USA 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012) shihpiS-PKu jozienJBGGoense nikosNKLogothetis abartelsABartels poster CavusogluBU2012 2012 5 20 578 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler Department Logothetis http://www.ismrm.org/12/Session57.htm Melbourne, Australia 20th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2012) mustafaMCavusoglu abartelsABartels kuludagKUludag poster SchindlerKB2011 2011 11 41 800.21 In our subjective experience, there is a tight link between covert visual attention and ego-centric spatial attention. One key difference is that the latter can extend beyond the visual field, providing us with an accurate mental representation of an object’s location relative to our body position. A neural link between visual and ego-centric spatial attention is suggested by lesions in parietal cortex, that lead not only to deficits in covert visual attention, but frequently also to a disorder of ego-centric spatial awareness, known as hemi-spatial neglect. While parietal involvement in covert visual spatial attention has been much studied, relatively little is known about mental representations of the unseen space around us. In the present study we examined whether also unseen spatial locations beyond the visual field are represented in parietal activity, and how they are related to retinotopic representations. We employed a novel virtual reality (VR) paradigm during functional magnetic resonance imaging (fMRI), whereby observers were prompted to draw their spatial attention to the position of one of eight possible objects located around them in an octagonal room. By changing the observers’ facing direction every few trials, the egocentric location of objects was disentangled from their absolute position and from the objects’ identity. Thus, mental representations of egocentric space surrounding the observer were sampled eight-fold. De-coding results of a multivariate pattern analysis classifier (MVPA), but not univariate results, showed that egocentric spatial directions were specifically represented in parietal cortex. These representations overlapped only partly with visually driven retinotopic activity. Our results thus show that parietal cortex codes not only for retinotopic and visually accessible space, but also for egocentric locations of the three-dimensional space surrounding us, including unseen space. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Bülthoff http://www.sfn.org/AM2011/ Washington, DC, USA 41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011) aschindlerASchindler kleinermMKleiner abartelsABartels poster ReinlB2011 2011 11 41 487.14 In every day life we are usually exposed to dynamically changing faces rather than to their static snapshots. Despite this, the vast majority of neurophysiology and neuroimaging studies have examined responses to static pictures of faces. Therefore, only little is known about the extent to which neural circuitries exist that are specialized to process dynamic aspects of faces, or whether dynamic faces are processed the same way as static ones. One difficulty in answering this question lies in appropriate control stimuli between static and dynamic conditions, as the latter tend to elicit overall more neural activity. In the present study we circumvented this problem by testing for neural responses that are sensitive to the timeline of facial expression changes. We used a 2x2 factorial design, showing different types of video recordings of facial expressions in an event-related fMRI study. We varied the emotional content (factor ,,emotion“) by using emotional expressions that either increased or decreased in the intensity of fear. Additionally, both types of movies were then played forward in their original timeline (real sequence) or backward (artificial sequence), defining the second factor ,,time“. Our aim was to identify brain areas that react specifically to the provided frame-sequence (time effect: real vs. artificial) or to the differences in the displayed emotion-direction (emotion effect: increase vs. decrease). Time-sensitive responses were found in the superior frontal gyrus (STS), in the occipital face area (OFA) and in a prefrontal set of regions, but not in the fusiform face area (FFA), with generally higher responses to real as opposed to artificial timelines. Emotion-sensitive responses were identified in STS (with larger responses to increasing fear), as well as in a part of the right inferior frontal gyrus belonging to the action observation network (with larger responses to decreasing fear). Thus, dynamic face stimuli elicited timeline specific activity in particular parts of the classic face-processing network (STS and OFA, but not FFA), as well as in higher-level cognitive regions that most likely interpret the meaning of time-dependent information. Our results therefore provide evidence for mid- as well as high-level time-sensitive detectors in human face processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sfn.org/AM2011/ Washington, DC, USA 41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011) mreinlMReinl abartelsABartels poster ZaretskayaB2011 2011 11 41 800.14 One of the key real-world challenges to our visual system is posed by cluttered scenes and occluded objects. To make sense of such scenes, local elements belonging to the same object need to be perceptually grouped, also referred to as spatial binding problem. However, it remains unknown how and where in the brain the local information is grouped together to give rise to a holistic percept. In the current study we addressed this question with a novel bistable motion stimulus developed by Anstis and Kim (2011) that consists of four pairs of dots coherently moving on a circular path. The stimulus causes perception to alternate spontaneously between two interpretations: local dot motion and global motion of two imaginary squares. Using functional magnetic resonance imaging (fMRI), we found that activity in the right parietal cortex correlated specifically with global as compared to local perception periods. To test for a causal role of parietal function in perceptual grouping, we used transcranial magnetic stimulation (TMS) to temporarily disrupt activity in two subregions of the parietal cortex. TMS over one of the subregions - the right anterior intraparietal sulcus (IPS) - specifically affected the global percept durations without affecting the local ones. Our results provide causal evidence that IPS may play a crucial role in perceptual grouping of local elements into a holistic percept, suggesting it to be a common anatomical locus of attention, perceptual grouping and perceptual selection processes. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Scheffler http://www.sfn.org/AM2011/ Washington, DC, USA 41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011) nataliyaNZaretskaya abartelsABartels poster SchindlerKB2011_2 2011 10 12 40 In our subjective experience, there is a tight link between covert visual attention and egocentric spatial attention. One key difference is that the latter can extend beyond the visual field, providing us with an acurate mental representation of an object’s location relative to our body position. A neural link between visual and ego-centric spatial attention is suggested by lesions in parietal cortex, that lead not only to deficits in covert visual attention, but frequently also to a disorder of ego-centric spatial awareness, known as hemi-spatial neglect. While parietal involvement in covert visual spatial attention has been much studied, relatively little is known about mental representations of the unseen space around. In the present study we examined whether also unseen spatial locations beyond the visual field are represented in parietal activity, and how they are related to retinotopic representations. We employed a novel virtual reality (VR) paradigm during functional magnetic resonance imaging (fMRI), whereby observers were prompted to draw their spatial attention to the position of one of eight possible objects located around them in an octagonal room. By changing the observers’ facing direction every few trials, the ego-centric location of objects was disentangled from their absolute position and from the objectsâ identity. Thus, mental representations of egocentric space surrounding the observer were sampled eight-fold. Decoding results of a multivariate pattern analysis classifier (MVPA), but not univariate results, showed that egocentric spatial directions were specifically represented in parietal cortex. These representations overlapped only partly with visually driven retinotopic activity. Our results thus show that parietal cortex codes not only for retinotopic and visually accessible space, but also for ego-centric locations of the three-dimensional space surrounding us, including unseen space. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Bülthoff http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Heiligkreuztal, Germany 12th Conference of Junior Neuroscientists of Tübingen (NeNA 2011) aschindlerASchindler kleinermMKleiner abartelsABartels poster ZaretskayaAB2011 2011 10 12 53 Grouping local elements into a holistic percept, also known as spatial binding, is crucial for meaningful perception. Lesions in posterior parts of the brain are known to impair perceptual grouping, but in the healthy brain this process has only been studied indirectly. Here we use a novel bi-stable illusion, which induces alternating and mutually exclusive subjective experiences of either grouped (global) or ungrouped (local) elements, while the visual stimulation remains the same. We show that global perceptual periods are related to stronger brain activity in the parietal cortex and that they are selectively shortened when parietal activity is disturbed by brain stimulation. Our findings thus provide direct evidence that consciously experienced grouping is mediated by parietal function, similar to attention and perceptual selection. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Scheffler http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Heiligkreuztal, Germany 12th Conference of Junior Neuroscientists of Tübingen (NeNA 2011) nataliyaNZaretskaya SAnstis abartelsABartels poster 7044 2010 12 Resting state activity is brain activation that arises in the absence of any task, and is usually measured in awake subjects during prolonged fMRI scanning sessions where the only instruction given is to close the eyes and do nothing. It has been recognized in recent years that resting state activity is implicated in a wide variety of brain function. While certain networks of brain areas have different levels of activation at rest and during a task, there is nevertheless significant similarity between activations in the two cases. This suggests that recordings of resting state activity can be used as a source of unlabeled data to augment kernel canonical correlation analysis (KCCA) in a semisupervised setting. We evaluate this setting empirically yielding three main results: (i) KCCA tends to be improved by the use of Laplacian regularization even when no additional unlabeled data are available, (ii) resting state data seem to have a similar marginal distribution to that recorded during the execution of a visual processing task implying largely similar types of activation, and (iii) this source of information can be broadly exploited to improve the robustness of empirical inference in fMRI studies, an inherently data poor domain. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/WIML2010-Shelton.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf http://www.wimlworkshop.org/ Biologische Kybernetik Max-Planck-Gesellschaft Whistler, BC, Canada NIPS 2010 Women in Machine Learning Workshop (WiML 2010) en jsheltonJAShelton blaschkoMBBlaschko abartelsABartels poster 7096 2010 12 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/WSnips2010_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf http://nips.cc/Conferences/2010/Program/event.php?ID=2002 Biologische Kybernetik Max-Planck-Gesellschaft Whistler, BC, Canada NIPS 2010 Workshop on Learning and Planning from Batch Time Series Data en jsheltonJAShelton blaschkoMBBlaschko arthurAGretton JMüller efischerEFischer abartelsABartels poster 7056 2010 11 40 74.11 The model of “predictive coding” suggests that feedback from a higher- to a lower-order visual area carries predictions of lower-level neural activities, whereas the feedforward connections carry the residual errors between the predictions and the actual lower-level activities (Rao and Ballard, 1999). We tested this theory in context of processing of planar motion in early (foveal) visual cortex. In a 2x2 factorial design, human subjects either fixated (eyes still) or carried out smooth pursuit on a display containing a planar random dot-field that was either stationary or moving coherently in-plane. This led to four conditions: (a) fixation on static dot-field, (b) fixation on moving dot-field, (c) pursuit on static dot-field, (d) pursuit of moving dot-field (pursuit was locked to the dot-motion). Neural activity was measured using fMRI at 3T. If early visual cortex coded for retinal motion, (b) and (c) would be expected to activate early visual cortex equally, and more than (a) and (d). In contrast, predictive coding would result in different responses. In addition to the above, early visual cortex would also code the error signal for mismatches between retinal motion input and the prediction for retinal motion, based on e.g. pursuit-related efferent copies. Such mismatches between prediction and input would occur in (b) (retinal motion without prediction of it) and in (d) (absence of retinal motion despite prediction of it). Note that these mismatches are equivalent to the presence of objective motion in the display. Thus, predictive coding would lead to highest responses in (b) (error + input), medium responses in (c) (input only) and (d) (error only), and lowest response in (a). We found (across the whole brain) the only activity satisfying these criteria in the occipital poles. The occipital poles contain the foveal confluence of early visual areas V1-V3, and are thus the key candidate for the above hypothesis. Their responses matched the hypothesized pattern precisely. In contrast, activity in motion responsive areas such as V5/MT+ and parietal regions was mainly driven by eye-movements and by retinal motion. Offline eye-tracking revealed that our results cannot be explained by differential fixation accuracies across conditions. It remains to be elucidated whether predictive coding actually accounts for the results, or whether direct feedback of objective motion signals from higher-level areas sums up with retinal input to the response observed in the occipital pole. Nevertheless, our results let us conclude that activity in the foveal representation of the early visual cortex fully match the predictions of Rao and Ballard (1999) for predictive coding. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://www.sfn.org/am2010/index.aspx?pagename=abstracts_main Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 40th Annual Meeting of the Society for Neuroscience (Neuroscience 2010) en efischerEFischer hhbHHBülthoff nikosNKLogothetis abartelsABartels poster FischerBLB2010 Perception 2010 8 39 ECVP Abstract Supplement 95 Motion processing regions apart from V5+/MT+ are still relatively poorly understood. The cingulate sulcus visual area (CSv) in the dorsal posterior cingulate cortex (dPCC) was previously described to respond preferentially to coherent motion and implied in ego-motion processing. We used fMRI to compare responses of CSv/dPCC and of areas V5/MT and MST to distinct types of motion and self-motion cues such as retinal motion and objective motion, determined during pursuit. Both V5/MT and MST had a strong preference for contra- versus ipsi-lateral stimulation, no preference for 2D planar motion versus 3D flow, and reduced yet significant responses to random motion. In contrast, CSv/dPCC preferred 2D planar motion over 3D flow, showed no lateralization, and did not respond to random motion. All areas responded strongly to eye-movement related signals, however CSv responded more to ‘real’ motion than to retinal motion while the reverse was the case for V5/MT and MST. CSv/dPCC thus differs from other motion-responsive regions by its unique preference to full-field, coherent and planar motion cues and its enhanced capability to respond to real motion. These results place CSv/dPCC in a good position to process visual and non-visual cues related to self-induced motion, especially those associated to eye-movements. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://www.perceptionweb.com/abstract.cgi?id=v100307 Lausanne, Switzerland 33rd European Conference on Visual Perception efischerEFischer hhbHHBülthoff nikosNKLogothetis abartelsABartels poster 6570 2010 6 11 229 When both eyes are presented with dissimilar images, human observers report alternating percepts - a phenomenon known as binocular rivalry. Subjects were presented dichoptically with (1) a looming/receding starfield or (2) a looming/receding Shepard Zoom (Berger, Siggraph 2003), the visual equivalent of the Shepard tone illusion. In four psychophysical experiments, we investigated the influence of (1) a real complex tone rising/falling in pitch and (2) rising/falling Shepard tones on the dominance and suppression times of the rivaling visual motion percepts (relative to non-motion sounds or no sounds). First, we observed longer dominance times of looming than receding visual percepts even in the absence of sound. Second, auditory looming signals enhanced this looming bias by lengthening the dominance periods of their congruent visual looming percept. Third, receding auditory motion signals reduced the perceptual looming bias, though this effect was less pronounced and not consistently observed. Collectively, the results show that the perceptual predominance of looming relative to receding visual motion is amplified by congruent looming/receding auditory signals during binocular rivalry. Auditory looming/receding signals may influence the dominance times of their congruent and incongruent visual percepts via genuine multisensory and higher order attentional mechanisms at multiple levels of the cortical hierarchy. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://imrf.mcmaster.ca/IMRF/ocs2/index.php/imrf/2010/paper/view/229 Biologische Kybernetik Max-Planck-Gesellschaft Liverpool, UK 11th International Multisensory Research Forum (IMRF 2010) en conradVConrad kleinermMKleiner jhartcherJHartcher-O&lsquo;Brien abartelsABartels hhbHHBülthoff unoppeUNoppeney poster ZaretskayaTLB2010 2010 6 16 145 MT-AM 8 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Scheffler http://www.humanbrainmapping.org/files/2010MeetingFiles/OHBM%202010%20Abstract%20Book.pdf Barcelona, Spain 16th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2010) nataliyaNZaretskaya thielscherAThielscher nikosNKLogothetis abartelsABartels poster 6162 2009 10 39 558.21 Self- and object-motion processing greatly relies on visual cues. There are at least two entirely independent kinds of self-induced visual motion that combine to optic flow in the visual field: expansion flow, such as that induced by forward motion in depth, or planar motion, such as induced by translational self-motion or by pursuit eye movements across a visual scene. In real life, both signals may occur in combination, yet, only one of the cues may be of behavioral relevance, thus requiring to be selectively attended to. In this fMRI study we attempt to address the question whether differential neural substrates get modulated by selective attention to either one of these motion cues. We created a stimulus combining an expansion flow pattern with translational motion on the same set of dots. In a feature-based detection task, subjects selectively attended either to the expansion or to the translation component of the stimulus and reported changes in the speed of the attended motion component. In control conditions that used the same stimuli subjects attended to color hue changes of the fixation cross, or passively fixated the stimulus without any attentional demand. In each of the three attention conditions, the attentional load was kept constant across conditions by a continuously updating staircase procedure. We found that attention to expansion modulated the separately localized areas MT/V5, MST, and V3A significantly more than attention to translation. This is in line with stimulus-driven studies that showed a preference to expansion/contraction stimuli in these areas (Smith et al., 2006). In contrast, V7 and the cingulate sulcus visual area (CSv) differed from all other regions, in that they did not show any selective modulation by attention to expansion flow. Most interestingly, we found motion selective modulation in the foveal confluence of V1, despite a physical match between stimulus conditions. This might be due to differential attentional enhancement within V1, or by differential feedback from higher regions such as MT/V5, MST or V3A. Our results therefore show a differential attentional modulation within the motion-processing pathway, depending on the type of motion-component that is attended to within the same flow stimulus. Smith AT, Wall MB, Williams AL, Singh KD (2006) Sensitivity to optic flow in human cortical areas MT and MST. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=3b1b2e24-3671-4e3d-9051-5dfbb3c15f6c&cKey=81bf6c91-1c74-4f55-870b-c12dbcb94af7 Biologische Kybernetik Max-Planck-Gesellschaft Chicago, IL, USA 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009) en efischerEFischer hhbHHBülthoff nikosNKLogothetis abartelsABartels poster 6287 2009 10 39 651.13 Electroencephalography (EEG) is a non-invasive neuroimaging tool which can be used to measure brain activity with excellent temporal resolution. By solving the so-called ‘inverse problem’, one can not only study the time-course of activation during a particular task, but also identify the location of the underlying neural sources in the brain. Usually, these methods are applied to averaged data obtained from EEG recordings during which volunteers perform a given, usually brief (0.1-5s) task over many dozens repetitions. This averaging across many brief trials results in clearer responses, as artifactual or randomly occurring events (noise, eye blinks, eye wanderings, etc) will be reduced. Here, we take a radically new approach, and ask whether one can obtain reliable source localization associated to a particular stimulus feature (such as visual contrast) when using complex natural stimuli presented over long periods of time. We made EEG recordings (64 channels) in 7 subjects who passively watched 2 minute long segments from different commercially available movies (the segments were repeated 20 times). We then developed a method based on independent component analysis (ICA) to reject EEG artifacts due to blinks, subject movement, etc. Source localization of this artifact-free data was calculated at each time point of the movie using low resolution electromagnetic tomography (LORETA). We then calculated the correlation coefficient between variations in the EEG source strength in over 6000 voxels within the brain with variations in movie contrast. As expected, we found that visual contrast in the movie mapped specifically to voxels within area V1, thus showing that a feature that varies continuously in its strength can be reliably mapped onto the cortical region involved in its processing. These findings open a new approach to mapping brain function with a high temporal resolution and allow the localization of a multitude of brain areas based on a single experiment using uncontrolled, natural stimuli. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=b20c565a-8249-480b-8c35-daf17e2d8523&cKey=e1de2d8a-b4aa-4d62-adc3-a4d2b575c82a Biologische Kybernetik Max-Planck-Gesellschaft Chicago, IL, USA 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009) en kevinKSWhittingstall abartelsABartels SKwon vsinghVSingh nikosNKLogothetis poster 5949 2009 7 10 590 102-103 Introduction When the two eyes are presented with dissimilar images, human observers report alternating percepts – a phenomenon coined binocular rivalry. These perceptual fluctuations reflect competition between the two visual inputs both at lower, monocular and at binocular, higher-level processing stages. Even though perceptual transitions occur stochastically over time, their temporal dynamics can be modulated by changes in stimulus strength, context and attention. While increases in stimulus strength (such as contrast) primarily abbreviate suppression phases of a percept, attentional and contextual factors predominantly lengthen its dominance periods. Goals This project investigates the influence of concurrent auditory stimulation on the temporal dynamics of binocular rivalry. In two psychophysics studies, we investigated whether sounds that provide directionally congruent, incongruent or no motion information modulate the dominance periods of rivaling visual motion percepts. Methods In the first psychophysics study, observers dichoptically viewed random-dot kinematograms (RDK) at 0% motion coherence in one eye and 50% in the other in a stereoscope, while being concurrently presented with directionally congruent auditory motion, noise and no sound. In the second psychophysics study, they viewed two RDKs of opposite motion directions at 100% coherence, with the auditory motion stimulus being directionally congruent with one of the two rivaling motion percepts. In both experiments, congruent auditory motion was temporally synchronized with visual motion to facilitate audio-visual integration into a coherent percept. Initial results Both experiments consistently revealed a statistically significant influence of sound on perceptual dominance times. In the first experiment, directionally congruent auditory motion but not noise increased the duration of the dominance phases of the RDK at 50% motion coherence. In the second experiment, auditory motion lengthened the dominance periods of the directionally congruent 100% RDK and abbreviated those of the directionally incongruent 100% RDK. Initial conclusions The results demonstrate that auditory stimuli influence the temporal dynamics of binocular rivalry. Auditory motion lengthened the dominance periods of a visual motion percept when it was directionally congruent, but shortened them when it was directionally incongruent. Thus, the (in)congruency of auditory motion primarily influences the duration of the dominance periods similar to purely visual contextual effects, even though a small effect was also observed on the suppression periods. In conclusion, the human brain draws on information from multiple senses to arbitrate between multiple rivaling perceptual interpretations. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Research Group Noppeney http://imrf.mcmaster.ca/IMRF/ocs/index.php/meetings/2009/paper/view/590 Biologische Kybernetik Max-Planck-Gesellschaft New York, NY, USA 10th International Multisensory Research Forum (IMRF 2009) en conradVConrad abartelsABartels kleinermMKleiner unoppeUNoppeney poster 5935 2009 7 Kernel Canonical Correlation Analysis (KCCA) is a general technique for subspace learning that incorporates principal components analysis (PCA) and Fisher linear discriminant analysis (LDA) as special cases. By finding directions that maximize correlation, CCA learns representations tied more closely to underlying process generating the the data and can ignore high-variance noise directions. However, for data where acquisition in a given modality is expensive or otherwise limited, CCA may suffer from small sample effects. We propose to use semisupervised Laplacian regularization to utilize data that are present in only one modality. This approach is able to find highly correlated directions that also lie along the data manifold, resulting in a more robust estimate of correlated subspaces. Functional magnetic resonance imaging (fMRI) acquired data are naturally amenable to subspace techniques as data are well aligned. fMRI data of the human brain are a particularly interesting candidate. In this study we implemented various supervised and semi-supervised versions of CCA on human fMRI data, with regression to single and multivariate labels (corresponding to video content subjects viewed during the image acquisition). In each variate condition, the semi-supervised variants of CCA performed better than the supervised variants, including a supervised variant with Laplacian regularization. We additionally analyze the weights learned by the regression in order to infer brain regions that are important to different types of visual processing. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications//fileadmin/user_upload/files/publications/pdf1236.pdfchen-b-1_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf Department Logothetis http://bbci.agilemeetings.com/ Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany Berlin BCI Workshop 2009: Advances in Nanotechnology en jsheltonJAShelton blaschkoMBBlaschko chlCHLampert abartelsABartels poster 6177 2009 3 2009 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www2.mrc-lmb.cam.ac.uk/groups/srw/cns/ Biologische Kybernetik Max-Planck-Gesellschaft Cambridge, UK 21st Cambridge Neuroscience Seminar: New Approaches in Neuroscience (CNS 2009) en stoewerSStoewer JDuncan abartelsABartels georgeGAKeliris nikosNKLogothetis natashaNSigala poster 5293 2008 11 38 461.19 For the successful estimation of self-motion based on visual cues it is necessary to take self-induced motion signals into account, such as those induced by eye-movements. In this fMRI study we used stimulus conditions that allowed us to differentiate neural responses to (a) retinal motion, (b) eye-movements (visual pursuit) and (c) objective motion. Responses to these three motion cues were measured in context of two types of visual stimuli, namely moving 2D dot-sheets and 3D-expanding flow fields. An additional localizer experiment segregated responses to contra- and ipsi-lateral stimulation as well as to full field coherent expansion as opposed to trajectory matched scrambled random motion. We found that MT/V5 and MST responded primarily to retinal motion and to eye-movements. More parietal regions such as V7 and IPS (intra-parietal sulcus) and a region recently implicated in self-motion processing, the cingulate sulcus visual area (CSv), seem to be driven by all three motion cues. The localizer experiment revealed that all of these regions responded almost exclusively to coherent motion types, while MT+/V5+ also responded, but less strongly, to the matched random motion display. CSv differed from all other regions in that it favored 2D translational coherent motion over 3D expanding flow fields, and in that its responses to ipsi- and contralateral flow were indistinguishable. It thus appears to be a strong candidate for integrating translational motion signals of retinal and non-retinal origin. Area V3A/B differed from most other motion processing regions in that it was primarily affected by objective motion, and also, but less, by visual pursuit. Furthermore, in the localizer it responded equally to coherent 3D flow and to the random motion stimulus. This suggests that V3A/B processes differential rather than coherent or self-induced motion. Our results lead us to suggest that there is a clear functional segregation among higher level motion processing regions in context of self-motion processing cues. It remains to be resolved to which extent the distinct regions inter-operate in a hierarchical or rather in a parallel fashion. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://www.sfn.org/am2008/ Biologische Kybernetik Max-Planck-Gesellschaft Washington, DC, USA 38th Annual Meeting of the Society for Neuroscience (Neuroscience 2008) efischerEFischer hhbHHBülthoff nikosNKLogothetis abartelsABartels poster FischerBLB2008 2008 10 9 5 For the successful estimation of self-motion based on visual cues it is necessary to take self-induced motion signals into account, such as those induced by eye-movements. In this fMRI study we used stimulus conditions that allowed us to differentiate neural responses to (a) retinal motion, (b) eye-movements (visual pursuit) and (c) objective motion. Responses to these three motion cues were measured in context of two types of visual stimuli, namely moving 2D dot-sheets and 3D-expanding ow fields. An additional localizer experiment segregated responses to contra- and ipsi-lateral stimulation as well as to full field coherent expansion as opposed to trajectory matched scrambled random motion. We found that MT/V5 and MST responded primarily to retinal motion and to eye-movements. More parietal regions such as V7 and IPS (intra-parietal sulcus) and a region recently implicated in self-motion processing, the cingulate sulcus visual area (CSv), seem to be driven by all three motion cues. The localizer experiment revealed that all of these regions responded almost exclusively to coherent motion types, while MT+/V5+ also responded, but less strongly, to the matched random motion display. CSv differed from all other regions in that it favored 2D translational coherent motion over 3D expanding ow fields. Also, its responses to ipsi and contralateral ow were indistinguishable. It thus appears to be a strong candidate for integrating translational motion signals of retinal and non-retinal origin. Area V3A/B differed from most other motion processing regions in that it was primarily affected by objective motion, and also, but less, by visual pursuit. Furthermore, in the localizer it responded equally to coherent 3D now and to the random motion stimulus. This suggests that V3A/B processes differential rather than coherent or self-induced motion. Our results lead us to suggest that there is a clear functional segregation among higher level motion processing regions in context of self-motion processing cues. It remains to be resolved to which extent the distinct regions inter-operate in a hierarchical or rather in a parallel fashion. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Ellwangen, Germany 9th Conference of the Junior Neuroscientists of Tübingen (NeNa 2008) efischerEFischer hhbHHBülthoff nikosNKLogothetis abartelsABartels poster 5289 Perception 2008 8 37 ECVP Abstract Supplement 128 We will discuss our attempts to study neural correlates of the perceptual alternations experienced upon viewing of ambiguous figures, and relate them to new psychophysical evidence offering a new twist in the eye-versus-percept debate. Our studies over the last decade indicated that perception-responsive cells are concentrated in cortical areas near the top of the processing hierarchy, but that they can be found all along the visual pathway. Similarly, psychophysics has shown that both, monocular as well as binocular, percept based neural representations contribute to perceptual dominance. Our new psychophysical evidence suggests a time-dependence of eye and percept contributions in binocular rivalry: initially a given monocular channel has greater influence on dominance, regardless of the percept. Over time, this reverses, with percept-related (ie eye-independent) processes increasingly 'urging' for a perceptual switch. We suggest this may reflect a single process, where monocular as well as binocular neural stages affect each other in a feedback-loop that evolves over time. Understanding rivalry thus calls for the study of networks rather than single neurons. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.perceptionweb.com/abstract.cgi?id=v080459 Biologische Kybernetik Max-Planck-Gesellschaft Utrecht, Netherlands 31st European Conference on Visual Perception en abartelsABartels nikosNLogothetis poster 5288 2008 7 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Brisbane, Australia Asia-Pacific Conference on Vision (APCV 2008) seymourKSeymour CClifford nikosNLogothetis abartelsABartels poster 5287 NeuroImage 2008 6 41 Supplement 1 S147 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Melbourne, Australia 14th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2008) seymourKSeymour CClifford nikosNLogothetis abartelsABartels poster 5285 2007 3 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Erice, Italy V. Workshop of the International School on Magnetic Resonance and Brain Function (ISMRBF 2007) abartelsABartels kmoutouKMoutoussis markMaugath SZeki nikosNLogothetis poster 4296 Human Brain Mapping 2006 6 6 1 1 1 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft WSchneider SSiegle abartelsABartels EFormisano RGoebel TMitchell TNichols UHasson JHaxby poster 5284 2006 6 37 In traditional functional magnetic resonance imaging (fMRI) carefully controlled stimuli are used to reveal cortical regions that are differentially responsive to distinct stimuli. In human fMRI studies we have shown that the varying intensity of features, such as faces or color, seen in a movie, can be used to map feature selective regions, such as the human V4 complex for color or superior temporal regions (STS) and lateral fusiform cortex (FFA) for faces (Bartels & Zeki, 2004). Here we applied the same paradigm in the anesthetized monkey to identify regions involved in processing various low- and highlevel features. The advantage of this approach is that effects of attention or eye-movements can be excluded. In early visual cortex (V1-V3) we found that the BOLD signal was predicted by both, changes in frame-by-frame pixel intensities (luminance changes) as well as by image contrast. These two measures were not correlated with each other in our movie stimulus. Early visual cortex thus seems to code for two independent stimulus dimensions. Responses to each were so specific that we were able to obtain retinotopic maps by correlating voxel-time series with time series of either of these stimulus dimensions as a function of their spatial location in the movie display. In contrast, color and face variations correlated most with BOLD signal changes in V4 and in the STS. In auditory cortex, we were able to obtain tonotopic maps based on the movie soundtrack, by correlating sound intensities at different frequencies with BOLD signal of every voxel. Our results illustrate that, in monkey as in man, movies - even though uncontrolled - allow surprisingly specific mapping of high- as well as low-level features, down to retinotopy and tonotopy. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.areadne.org/2006/ Biologische Kybernetik Max-Planck-Gesellschaft Santorini, Greece AREADNE 2006: Research in Encoding and Decoding of Neural Ensembles en abartelsABartels markMaugath kmoutouKMoutoussis SZeki nikosNLogothetis poster 3831 2005 11 35 46.11 In traditional functional magnetic resonance imaging (fMRI) carefully controlled stimuli are used to reveal cortical regions that are differentially responsive to distinct stimuli. In human fMRI studies we have shown that the varying intensity of features, such as faces or color, seen in a movie, can be used to map feature selective regions, such as the human V4 complex for color or superior temporal regions (STS) and lateral fusiform cortex (FFA) for faces (Bartels &amp;amp;amp; Zeki, 2004). Here we applied the same paradigm in the anesthetized monkey to identify regions involved in processing various low- and high-level features. The advantage of this approach is that effects of attention or eye-movements can be excluded. We found that the BOLD signal in V1 was best predicted by changes in frame-by-frame pixel intensities (contrast changes) compared to measures of contrast, luminance or spatial frequency. BOLD signal in response to contrast changes were specific enough to reveal the retinotop y of V1 and V2 as a function of their spatial location throughout the movie. Color variations correlated most with BOLD signal in V4 and weakly along the STS. Face specific responses extended along the STS, and overlapped partly with the regions also responsive to color. We conclude that, in monkey as in man, movies - even though uncontrolled - allow surprisingly specific mapping of high- as well as low-level features, down to retinotopy. In addition, regions identified this way may reflect more realistically processing in natural, more complex and dynamic environments. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sfn.org/absarchive/ Biologische Kybernetik Max-Planck-Gesellschaft Washington, DC, USA 35th Annual Meeting of the Society for Neuroscience (Neuroscience 2005) en abartelsABartels markMAugath kmoutouKMoutoussis SZeki nikosNKLogothetis poster 3890 2004 10 34 176.1 The cerebral cortex has predominantly been studied using abstract, simplified and often unnatural stimuli. We therefore wanted to characterize cortical function during natural viewing conditions, especially to determine the degree to which distinct cortical regions are differentially involved in the processing of distinct features. In a previous study, we used fMRI data from 8 human volunteers who freely viewed the first 25 min of a James Bond movie, and showed that the intensity variation over time of high-level features (faces, human bodies, language and color) as judged offline by separate human observers correlated linearly with the BOLD signal of specialized, partially segregated cortical regions (Bartels and Zeki, 2004a). To complement the previous study, here we used a computational analysis of the movie to determine the intensities of low-level features over time. These included global and local motion flow-fields, frame-by-frame pixel errors, contrast, luminance and color saturation. Parallel to our previous findings, our results showed that partially segregated regions of the visual system correlated with distinct low-level features, in accord with their preferences known from controlled experiments. The results also complement our findings from an independent component analysis of the same dataset (Bartels and Zeki, 2004b), in which a multitude of distinct cortical regions was segregated without a-priori hypotheses about their function, based entirely on their differential and specific functional response to the movie over time. In conjunction with our previous findings we conclude that during processing of dynamic, complex natural scenes distinct regions of the visual brain maintain a high degree of functional preference for distinct visual features. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.sfn.org/absarchive/ Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 34th Annual Meeting of the Society for Neuroscience (Neuroscience 2004) abartelsABartels SZeki nikosNKLogothetis conference bartels2011 2011 5 12 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Max Planck Institute for Biological Cybernetics Tübingen, Germany Institut für Neurobiologie, Universität Tübingen abartelsABartels conference 6381 2010 3 14 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Stuttgart, Germany Staatstheater Stuttgart, öffentliche Expertenrunde de abartelsABartels conference 6380 2010 2 22 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.cin.uni-tuebingen.de/fileadmin/pdfs/Events/Broschuere_fin-1_Giese.pdf Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany Symposium "Neural Encoding of Perception and Action" en abartelsABartels conference 6378 2010 1 26 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Freiburg, Germany Studium Generale, Universität Freiburg de abartelsABartels conference 6379 2010 1 9 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Rigi-Kulm, Schweiz Jahrestagung Forum für Organisationsentwicklung Schweiz de abartelsABartels conference 6142 2009 12 9 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.neuroscience-berlin.de/bbd/bbd-archive/article/bbd-program-locations-2009/ Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany Berlin Brain Days abartelsABartels conference 6141 2009 9 24 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.esf.org/activities/exploratory-workshops/humanities-sch/workshops-detail.html?ew=8172 Biologische Kybernetik Max-Planck-Gesellschaft Milano, Italy ESF Exploratory Workshop on Neuroesthetics: Where Art and the Brain Collide abartelsABartels conference 6140 2009 9 11 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany Lectures on fMRI - European Society for Magnetic Resonance in Medicine and Biology abartelsABartels conference 5971 2009 7 5 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.pmu.ac.at/de/1896.htm Biologische Kybernetik Max-Planck-Gesellschaft Salzburg, Austria Neurobiologie der Psychotherapie, Beziehung und Komplexität abartelsABartels conference 5970 2009 6 23 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Goteborg, Sweden 19th World Congress for Sexual Health abartelsABartels conference 5969 2009 5 20 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Lausanne, Switzerland Colloques des Neurosciences - Centre Hospitalier Universitaire Vaudois (CHUV) abartelsABartels conference 5768 2009 2 9 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.carls.keio.ac.jp/english/2009/02/the-international-symposium-emotional-animals-sensible-humans-is-held-on-8-9th-february-2009.html Biologische Kybernetik Max-Planck-Gesellschaft Tokyo, Japan Centre for Advanced Research on Logic and Sensibility (CARLS) Symposium “"Emotional Animals, Sensible Humans”" - Keio University abartelsABartels conference 5623 2008 12 19 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Zürich, Switzerland Neurocolloquium abartelsABartels conference 5769 2008 12 18 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.cin.uni-tuebingen.de/events/past-events/2008-events.php Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany Junior Research Group Selection Symposium 5: Werner Reichardt Centre for Integrative Neuroscience abartelsABartels conference 5622 2008 12 15 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Mannheim, Germany Neurowissenschaftliches Kolloquium abartelsABartels conference 5291 2008 9 16 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://nguyendangbinh.org/Proceedings/FG08/proceedings/content/workshops.htm Biologische Kybernetik Max-Planck-Gesellschaft Amsterdam, Netherlands Workshop on Psychology of Face and Gesture Recognition abartelsABartels conference 5290 Frontiers in Human Neuroscience 2008 9 4 Conference Abstract: 10th International Conference on Cognitive Neuroscience Binocular rivalry is scientifically attractive because it allows the study of an entirely subjective experience using objective measurements: During rivalry the visual percept changes dramatically – from one image to another – while the two stimuli presented to the eyes remain constant. There are at least two aspects whose neural origin would be worthwhile understanding: 1. The mechanisms that lead to the stochastic, spontaneous, and sometimes abrupt alternations of the percept from one stimulus to the other; 2. The mechanisms that keep one stimulus dominant, perceived, and the other suppressed. Previous psychophysical studies have elegantly demonstrated that both monocular and binocular sites contribute to perceptual alternations and to perceptual dominance. Recordings from single neurons, from monocular cells in V1 to cells in the prefrontal cortex show signals representing both the suppressed as well as the dominant stimuli. The proportion of neurons exhibiting percept-modulated responses rises from V1, through V4/V5, IT to prefrontal cortex. Additionally, some studies have reported that certain bands of local field potentials in V1 contain more information about the percept than spikes, while fMRI results in the human brain even show perceptual modulations in the LGN. Like psychophysics, physiology points toward a potentially complex interaction of several neural sites involved in rivalry. We will present the latest recordings from hundreds of neurons in V1, as well as initial recordings from prefrontal cortex. We will mainly focus however, on new psychophysical results shedding light on the eye-versus-percept debate. These results suggest a time-dependence of eye and percept contributions in binocular rivalry. During a dominance period, it appears that it is initially a given monocular channel that has major influence on dominance, regardless of the percept. Over time, this reverses, with image-related, eye-independent processes increasingly controlling any perceptual switch. Our results lead us to suggest that monocular effects – as observed here and in previous studies – may directly depend on higher-level effects and vice versa, because monocular as well as higher-level perceptual influences on dominance vary in parallel but with opposite signs over time. Therefore, the monocular and binocular effects observed in binocular rivalry may reflect different ends of a single process affecting several neural stages. A potential model could be that an initially strong stimulus representation is stabilized by a reinforcing, noise-reducing loop between binocular and monocular stages. As the stability of this process weakens, both the monocular channel loses influence, and the binocular stimulus representation weakens, increasingly favoring a perceptual switch. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Abstract Talk http://www.frontiersin.org/10.3389/conf.neuro.09.2009.01.048/event_abstract Biologische Kybernetik Max-Planck-Gesellschaft Bodrum, Turkey 10th International Conference on Cognitive Neurosciences (ICON 2008) 10.3389/conf.neuro.09.2009.01.048 abartelsABartels theofanisTPanagiotaropoulos georgeGAKeliris nikosNKLogothetis conference 5418 2008 7 21 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Barcelona, Spain Euroscience Open Forum (ESOF 2008) abartelsABartels conference 5419 2008 5 15 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany Tübinger Neurokolloquium: Attempto-Preis-Vorlesung abartelsABartels conference 5420 2008 4 18 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Zürich, Switzerland Kolloquium Institute of Neuroinformatics, University of Zürich / ETH abartelsABartels conference 5421 2008 3 12 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Zürich, Switzerland University of Zürich Brainfair abartelsABartels conference 5422 2008 2 14 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Lausanne, Switzerland University D-Day abartelsABartels conference 5423 2007 12 6 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Freiburg, Germany Neurokolloquium of the University Freiburg abartelsABartels conference 5426 2007 1 20 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft San Francisco, CA, USA Smith-Kettlewell Eye Research Institute Seminar series abartelsABartels conference 5424 2007 1 20 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany Tübinger Neuro-fMRI course abartelsABartels conference 5425 2007 1 18 Love is a highly rewarding experience that underlies bonding – whether between adult partners or parent and child. It is thus part of a biological mechanism of existential importance for species bearing non-autonomous offspring. My lecture will review – from a biological perspective – evolutionary as well as physiological fundaments of partner selection and bonding (maternal as well as between adults). In particular I will report the results of the fi rst two human functional magnetic resonance imaging (fMRI) studies that reveal neural substrates involved in both romantic and maternal love, and highlight commonalities as well as differences of our results with those obtained in other species. In particular, I hope our research will encourage further studies into the physiological foundations of human bonding, which, in contrast to corresponding research in animals or in human psychology, has faced a curious hesitation until recently. Our studies revealed highly overlapping brain regions between the two types of love. The activated regions are related to the reward system and coincided with areas rich in receptors for the neurohormones oxytocin and vasopressin, which have been shown in animals to be both necessary and suffi cient to induce bonding. The hypothalamus, involved in sexual arousal, was activated only with romantic attachment, and constitutes one of several differentially activated regions with the two types of love. Finally, both studies revealed a common set of de-activated regions associated with negative emotions, social judgment and ‘mentalizing’, that is, the assessment of other people’s intentions and emotions. Human attachment seems thus to employ a push– pull mechanism activated when individuals face a loved one. This overcomes social distance by deactivating networks used for critical social assessment and negative emotions, and while it bonds individuals through the involvement of the reward circuitry, explaining the power of love to motivate and exhilarate. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://plaisir.berkeley.edu/conference6/schedule.htm Biologische Kybernetik Max-Planck-Gesellschaft Berkeley, CA, USA Sixth International Conference of Neuroesthetics: The Neurobiology of Love abartelsABartels conference 5427 2006 11 21 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Freiburg, Germany Neuro-Kolloquium der Albert-Ludwigs-Universität Freiburg abartelsABartels conference 5428 2006 10 24 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Mannheim, Germany Neurokolloquium of the Institute of Psychiatry abartelsABartels conference 5430 2006 5 26 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany 30. Jahrestagung der Akademie für Sexualmedizin abartelsABartels conference 5429 2006 5 26 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Sils-Maria, Switzerland Ost-West Congress (Management Meeting) abartelsABartels conference 5431 2006 4 24 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Biologische Kybernetik Max-Planck-Gesellschaft Paris, France European Society for Biomedical Research on Alcoholism: Brain imaging and addictions abartelsABartels conference 5432 2006 3 24 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://test-unipi.adm.unipi.it/ateneo/comunica/eventi/archivio/anniprec/2006/marzo/psychiatry.htm_cvt.htm Biologische Kybernetik Max-Planck-Gesellschaft Roma, Italy International Conference on Hot Issues in Psychiatry abartelsABartels