This file was created by the Typo3 extension sevenpack version 0.7.14 --- Timezone: CEST Creation date: 2013-05-25 Creation time: 17-08-01 --- Number of references 51 article LeitaoTWPN2012 Cerebral Cortex 2013 4 23 4 873-884 Accumulating evidence suggests that multisensory interactions emerge already at the primary cortical level. Specifically, auditory inputs were shown to suppress activations in visual cortices when presented alone but amplify the blood oxygen level–dependent (BOLD) responses to concurrent visual inputs (and vice versa). This concurrent transcranial magnetic stimulation–functional magnetic resonance imaging (TMS-fMRI) study applied repetitive TMS trains at no, low, and high intensity over right intraparietal sulcus (IPS) and vertex to investigate top-down influences on visual and auditory cortices under 3 sensory contexts: visual, auditory, and no stimulation. IPS-TMS increased activations in auditory cortices irrespective of sensory context as a result of direct and nonspecific auditory TMS side effects. In contrast, IPS-TMS modulated activations in the visual cortex in a state-dependent fashion: it deactivated the visual cortex under no and auditory stimulation but amplified the BOLD response to visual stimulation. However, only the response amplification to visual stimulation was selective for IPS-TMS, while the deactivations observed for IPS- and Vertex-TMS resulted from crossmodal deactivations induced by auditory activity to TMS sounds. TMS to IPS may increase the responses in visual (or auditory) cortices to visual (or auditory) stimulation via a gain control mechanism or crossmodal interactions. Collectively, our results demonstrate that understanding TMS effects on (uni)sensory processing requires a multisensory perspective. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Research Group Noppeney Department Scheffler http://cercor.oxfordjournals.org/content/23/4/873.full.pdf+html 10.1093/cercor/bhs078 joanaleitaoJLeitão thielscherAThielscher sebastianwernerSWerner rolfRPohmann unoppeUNoppeney article WindhoffOT2011 Human Brain Mapping 2013 4 34 4 923–935 The need for realistic electric field calculations in human noninvasive brain stimulation is undisputed to more accurately determine the affected brain areas. However, using numerical techniques such as the finite element method (FEM) is methodologically complex, starting with the creation of accurate head models to the integration of the models in the numerical calculations. These problems substantially limit a more widespread application of numerical methods in brain stimulation up to now. We introduce an optimized processing pipeline allowing for the automatic generation of individualized high-quality head models from magnetic resonance images and their usage in subsequent field calculations based on the FEM. The pipeline starts by extracting the borders between skin, skull, cerebrospinal fluid, gray and white matter. The quality of the resulting surfaces is subsequently improved, allowing for the creation of tetrahedral volume head meshes that can finally be used in the numerical calculations. The pipeline integrates and extends established (and mainly free) software for neuroimaging, computer graphics, and FEM calculations into one easy-to-use solution. We demonstrate the successful usage of the pipeline in six subjects, including field calculations for transcranial magnetic stimulation and transcranial direct current stimulation. The quality of the head volume meshes is validated both in terms of capturing the underlying anatomy and of the well-shapedness of the mesh elements. The latter is crucial to guarantee the numerical robustness of the FEM calculations. The pipeline will be released as open-source, allowing for the first time to perform realistic field calculations at an acceptable methodological complexity and moderate costs. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler http://onlinelibrary.wiley.com/doi/10.1002/hbm.21479/pdf 10.1002/hbm.21479 mwindhoffMWindhoff aopitzAOpitz thielscherAThielscher article MoisaSPT2012 Journal of Neuroscience 2012 5 32 21 7244-7252 Primate electrophysiological and lesion studies indicate a prominent role of the left dorsal premotor cortex (PMd) in action selection based on learned sensorimotor associations. Here we applied transcranial magnetic stimulation (TMS) to human left PMd at low or high intensity while right-handed individuals performed externally paced sequential key presses with their left hand. Movements were cued by abstract visual stimuli, and subjects either freely selected a key press or responded according to a prelearned visuomotor mapping rule. Continuous arterial spin labeling was interleaved with TMS to directly assess how stimulation of left PMd modulates task-related brain activity depending on the mode of movement selection. Relative to passive viewing, both tasks activated a frontoparietal motor network. Compared with low-intensity TMS, high-intensity TMS of left PMd was associated with an increase in activity in medial and right premotor areas without affecting task performance. Critically, this increase in task-related activity was only present when movement selection relied on arbitrary visuomotor associations but not during freely selected movements. Psychophysiological interaction analysis revealed a context-specific increase in functional coupling between the stimulated left PMd and remote right-hemispheric and mesial motor regions that was only present during arbitrary visuomotor mapping. Our TMS perturbation approach yielded causal evidence that the left PMd is implicated in mapping external cues onto the appropriate movement in humans. Furthermore, the data suggest that the left PMd may transiently form a functional network together with right-hemispheric and mesial motor regions to sustain visuomotor mapping performed with the left nondominant hand. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler http://www.jneurosci.org/content/32/21/7244.full.pdf+html 10.1523/​JNEUROSCI.2757-11.2012 mariusMMoisa HRSiebner rolfRPohmann thielscherAThielscher article HelbigERPTMSN2011 NeuroImage 2012 4 60 2 1063–1072 Behaviourally, humans have been shown to integrate multisensory information in a statistically-optimal fashion by averaging the individual unisensory estimates according to their relative reliabilities. This form of integration is optimal in that it yields the most reliable (i.e. least variable) multisensory percept. The present study investigates the neural mechanisms underlying integration of visual and tactile shape information at the macroscopic scale of the regional BOLD response. Observers discriminated the shapes of ellipses that were presented bimodally (visual-tactile) or visually alone. A 2×5 factorial design manipulated (i) the presence vs. absence of tactile shape information and (ii) the reliability of the visual shape information (five levels). We then investigated whether regional activations underlying tactile shape discrimination depended on the reliability of visual shape. Indeed, in primary somatosensory cortices (bilateral BA2) and the superior parietal lobe the responses to tactile shape input were increased when the reliability of visual shape information was reduced. Conversely, tactile inputs suppressed visual activations in the right posterior fusiform, when the visual signal was blurred and unreliable. Somatosensory and visual cortices may sustain integration of visual and tactile shape information either via direct connections from visual areas or top-down effects from higher order parietal areas. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Research Group Ernst Department Scheffler Department Schölkopf Research Group Noppeney http://www.sciencedirect.com/science/article/pii/S1053811911011475 10.1016/j.neuroimage.2011.09.072 helbigHBHelbig marcMOErnst ricciardiERicciardi PPietrini thielscherAThielscher kamaKMMayer johannesJSchultz unoppeUNoppeney article OpitzWHTT2011 NeuroImage 2011 10 58 3 849-859 In transcranial magnetic stimulation (TMS), knowledge of the distribution of the induced electric field is fundamental for a better understanding of the position and extent of the stimulated brain region. However, the different tissue types and the varying fibre orientation in the brain tissue result in an inhomogeneous and anisotropic conductivity distribution and distort the electric field in a non-trivial way. Here, the field induced by a figure-8 coil is characterized in detail using finite element calculations and a geometrically accurate model of an individual head combined with high-resolution diffusion-weighted imaging for conductivity mapping. It is demonstrated that the field strength is significantly enhanced when the currents run approximately perpendicular to the local gyral orientation. Importantly, the spatial distribution of this effect differs distinctly between gray matter (GM) and white matter (WM): While the field in GM is selectively enhanced at the gyral crowns and lips, high field strengths can still occur rather deep in WM. Taking the anisotropy of brain tissue into account tends to further boost this effect in WM, but not in GM. Spatial variations in the WM anisotropy affect the local field strength in a systematic way and result in localized increases of up to 40% (on average ~ 7% for coil orientations perpendicular to the underlying gyri). We suggest that these effects might create hot spots in WM that might contribute to the excitation of WM structures by TMS. However, our results also demonstrate the necessity of using realistic nerve models in the future to allow for more definitive conclusions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler http://www.sciencedirect.com/science?_ob=MiamiImageURL&_cid=272508&_user=29041&_pii=S1053811911007154&_check=y&_origin=&_coverDate=01-Oct-2011&view=c&wchp=dGLbVlV-zSkzk&md5=6737c2fa4d1411ffe27f05291bda3256/1-s2.0-S1053811911007154-main.pdf 10.1016/j.neuroimage.2011.06.069 aopitzAOpitz mwindhoffMWindhoff RMHeidemann RTurner thielscherAThielscher article 6789 Cerebral Cortex 2011 7 21 7 1602-1612 The posterior parietal cortex (PPC) plays an important role in controlling voluntary movements by continuously integrating sensory information about body state and the environment. We tested which subregions of the PPC contribute to the processing of target- and body-related visual information while reaching for an object, using a reaching paradigm with 2 types of visual perturbation: displacement of the visual target and displacement of the visual feedback about the hand position. Initially, functional magnetic resonance imaging (fMRI) was used to localize putative target areas involved in online corrections of movements in response to perturbations. The causal contribution of these areas to online correction was tested in subsequent neuronavigated transcranial magnetic stimulation (TMS) experiments. Robust TMS effects occurred at distinct anatomical sites along the anterior intraparietal sulcus (aIPS) and the anterior part of the supramarginal gyrus for both perturbations. TMS over neighboring sites did not affect online control. Our results support the hypothesis that the aIPS is more generally involved in visually guided control of movements, independent of body effectors and nature of the visual information. Furthermore, they suggest that the human network of PPC subregions controlling goal-directed visuomotor processes extends more inferiorly than previously thought. Our results also point toward a good spatial specificity of the TMS effects. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Cerebral-Cortex-2010-Reichenbach_6789[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://cercor.oxfordjournals.org/content/21/7/1602.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.1093/cercor/bhq225 areichenAReichenbach brescianiJ-PBresciani APeer hhbHHBülthoff thielscherAThielscher article WehrlJTMSP2011 Magnetic Resonance in Medicine 2011 1 65 1 269-279 The combination of positron emission tomography and MR in one system is currently emerging and opens up new domains in the functional examinations of living systems. This article reports on relevant influences of a positron emission tomography insert on MR imaging. The basic conditions of main magnetic field and RF field homogeneity were measured as well as image quality and signal-to-noise ratio when applying the usual MR sequence types including echo-planar techniques. Moreover, the influence of the positron emission tomography insert on the RF noise level and on RF interferences was measured by comparing results achieved with and without the positron emission tomography insert. The temporal stability of EPI imaging with and without the positron emission tomography insert was assessed. Small but significant decreases in the signal-to-noise ratio were revealed when the positron emission tomography insert was present, whereas B(0) and B(1) homogeneity as well as RF noise level were not adversely affected. A higher signal intensity drift was found for EPI imaging studies; however, this can be compensated by post processing. In summary, this study shows that positron emission tomography inserts can be designed for and used within an MR system practically, without substantially affecting the MR image quality. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler http://onlinelibrary.wiley.com/doi/10.1002/mrm.22591/pdf 10.1002/mrm.22591 HFWehrl MSJudenhofer thielscherAThielscher PMartirosian FSchick BJPichler article 6724 Neuroimage 2011 1 54 2 1375-1384 Transcranial magnetic stimulation (TMS) can non-invasively modify cortical neural activity by means of a time-varying magnetic field. For example, in cognitive neuroscience, it is applied to create reversible “virtual lesions” in healthy humans (usually assessed as diminished performance in a behavioral task), thereby helping to establish causal structure–function relationships. Despite its widespread use, it is still rather unclear how TMS acts on existing, task-related neural activity, potentially resulting in a measurable effect on the behavioral level. Here, we deliver TMS to early visual areas while recording EEG in order to directly characterize the interaction between TMS-evoked (TEPs) and visual-evoked potentials (VEPs). Simultaneously, the subjects&amp;lsquo; performance is assessed in a visual forced-choice task. This allows us to compare the TMS effects on the VEPs across different levels of behavioral impairment. By systematically varying the stimulation intensity, we demonstrate tha t TMS strongly enhances the overall visual stimulus-related activity (rather than disrupting it). This enhancement effect saturates when behavior is impaired. This might indicate that the neural coding of the visual stimulus is robust to noise within a certain dynamic range (as indexed by the enhancement). Strong disturbances might saturate this range, causing behavioral impairment. Variation of the timing between the visual stimulus and the magnetic pulse reveals a “constructive interference” between the TEPs and VEPs: The better the overlap between both evoked potentials, the stronger the interaction effect when TMS and visual stimulation are combined. Importantly, however, this effect is uncorrelated with the strength of behavioral impairment. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Logothetis Department MRZ http://www.sciencedirect.com/science?_ob=MImg&amp;amp;_imagekey=B6WNP-50X2NG3-3-G&amp;amp;_cdi=6968&amp;amp;_user=29041&amp;amp;_pii=S1053811910011298&amp;amp;_origin=search&amp;amp;_coverDate=08%2F30%2F2010&amp;amp;_sk=999999999&amp;amp;view=c&amp;amp;wc Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuroimage.2010.08.047 areichenAReichenbach kevinKWhittingstall thielscherAThielscher article 6690 NeuroImage 2011 1 54 1 234-243 The spatial extent of the effects of transcranial magnetic stimulation (TMS) on neural tissue is only coarsely understood. One key problem is the realistic calculation of the electric field induced in the brain, which proves difficult due to the complex gyral folding pattern that results in an inhomogeneous conductivity distribution within the skull. We used the finite element method (FEM) together with a high-resolution volume mesh of the human head to better characterize the field induced in cortical gray matter (GM). The volume mesh was constructed from T1-weighted structural magnetic resonance images to allow for an anatomically accurate modeling of the gyrification pattern. Five tissue types were taken into account, corresponding to skin, skull, cerebrospinal fluid (CSF) including the ventricles as well as cortical gray and white matter. We characterized the effect of the current direction on the electric field distribution in GM. Importantly, the field strength in GM was increased by up to 51% when the induced currents were perpendicular to the local gyrus orientation. This effect was mainly restricted to the gyral crowns and lips, but did not extend into the sulcal walls. As a result, the focality of the fields induced in GM was increased. This enhancement effect might in part underlie the dependency of stimulation thresholds on coil orientation, as commonly observed in TMS motor cortex studies. In contrast to the clear-cut effects of the gyrification pattern on the induced field strength, current directions were predominantly influenced by the CSF-skull boundary. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WNP-50NYWV0-7-G&_cdi=6968&_user=29041&_pii=S1053811910010347&_origin=search&_coverDate=01%2F01%2F2011&_sk=999459998&view=c&wchp=dGLbVlz-zSkzV&md5=b4d491d16015c01bf5270cd64217cc49&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuroimage.2010.07.061 thielscherAThielscher aopitzAOpitz mwindhoffMWindhoff 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 6054 Cerebral Cortex 2010 2 20 2 328-338 In visual suppression paradigms, transcranial magnetic stimulation (TMS) applied ~90 ms after visual stimulus presentation over occipital visual areas can robustly interfere with visual perception, thereby most likely affecting feedback activity from higher areas (Amassian VE, Cracco RQ, Maccabee PJ, Cracco JB, Rudell A, Eberle L. 1989. Suppression of visual perception by magnetic coil stimulation of human occipital cortex. Electroencephalogr Clin Neurophysiol 74:458–462.). It is speculated that the observed effects might stem primarily from the disruption of V1 activity. This hypothesis, although under debate, argues in favor of a special role of V1 in visual awareness. In this study, we combine TMS, functional magnetic resonance imaging, and calculation of the induced electric field to study the neural correlates of visual suppression. For parafoveal visual stimulation in the lower right half of the visual field, area V2d is shown to be the likely TMS target based on its anatomical location close to the sk ull surface. Furthermore, isolated stimulation of area V3 also results in robust visual suppression. Notably, V3 stimulation does not directly affect the feedback from higher visual areas that is relayed mainly via V2 to V1. These findings support the view that intact activity patterns in several early visual areas (rather than merely in V1) are likewise important for the perception of the stimulus. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://cercor.oxfordjournals.org/cgi/reprint/bhp102v1 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1093/cercor/bhp102 thielscherAThielscher areichenAReichenbach KUgurbil kuludagKUludag article 5929 NeuroImage 2010 1 49 1 612-620 Continuous Arterial Spin Labeling (CASL) offers the possibility to quantitatively measure the regional cerebral blood flow (rCBF). We demonstrate, for the first time, the feasibility of interleaving Transcranial Magnetic Stimulation (TMS) with CASL at 3 T. Two different repetitive TMS (rTMS) protocols were applied to the motor cortex in 10 subjects and the effect on rCBF was measured using a CASL sequence with separate RF coils for labeling the inflowing blood. Each subject was investigated, using a block design, under 7 different conditions: continuous 2 Hz rTMS (3 intensities: 100%, 110% and 120% resting motor threshold [MT]), short 10 Hz rTMS trains at 110% MT (8 pulses per train; 3 different numbers of trains per block with 2, 4 and 12 s intervals between trains) and volitional movement (acoustically triggered by 50% MT stimuli). We show robust rCBF increases in motor and premotor areas due to rTMS, even at the lowest stimulation intensity of 100% MT. RCBF exhibited a linear positive dependency on stimula tion intensity (for continuous 2 Hz rTMS) and the number of 10 Hz trains in the stimulated M1/S1 as well as in premotor and supplementary motor areas. Interestingly, the 2 different rTMS protocols yielded markedly different rCBF activation time courses, which did not correlate with the electromyographic recordings of the muscle responses. In future, this novel combination of TMS with ASL will offer the possibility to investigate the immediate and after-effects of rTMS stimulation on rCBF, which previously was only possible using PET. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WNP-4WS2HW9-7-K&_cdi=6968&_user=29041&_orig=search&_coverDate=01%2F01%2F2010&_sk=999509998&view=c&wchp=dGLbVtz-zSkzS&md5=0c07d14134d790e237c2ec8c346cbd77&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuroimage.2009.07.010 mariusMMoisa rolfRPohmann kuludagKUludag thielscherAThielscher article 6052 NeuroImage 2009 10 47 4 1319-1330 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science?_ob=PdfDownloadURL&_uoikey=B6WNP-4W2NDR6-6&_tockey=%23toc%236968%232009%23999529995%231362071%23FLA%23&_orig=browse&_acct=C000003178&_version=1&_userid=29041&md5=13c440a3d2a4bf8f5065c36cc2e7d4e2 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuroimage.2009.04.021 thielscherAThielscher felixFAWichmann article 5995 The Journal of Physiology 2009 8 587 19 4605-4616 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://jp.physoc.org/content/early/2009/08/10/jphysiol.2009.176362.abstract Biologische Kybernetik Max-Planck-Gesellschaft en 10.1113/jphysiol.2009.176362 areichenAReichenbach thielscherAThielscher APeer hhbHHBülthoff brescianiJ-PBresciani article 5496 Journal of Magnetic Resonance Imaging 2009 1 29 1 189-197 Purpose To develop and test a novel method for the coil placement in interleaved Transcranial Magnetic Stimulation(TMS)/fMRI studies. Materials and Methods Initially, a desired TMS coil position at the subject’s head is recorded using a neuronavigation system. Subsequently, a custom-made holding device is used for coil placement inside the MR scanner. The parameters of the device corresponding to the prerecorded position are automatically determined from a fast structural image acquired directly before the experiment. The spatial accuracy of our method was verified on a phantom. Finally, in a study on 5 subjects, the coil was placed above the cortical representation of a hand muscle in M1 and the BOLD responses to short rTMS trains were assessed using EPI recordings. Results The spatial accuracy of our method is in the range of 2.9±1.3(SD) mm. Motor cortex stimulation resulted in robust BOLD activations in motor- and auditory-related brain areas, with the activation in M1 being localized in the hand knob. Conclusion We present a user-friendly method for TMS coil positioning in the MR scanner that exhibits good spatial accuracy and speeds up the setup of the experiment. The motor-cortex study proves the viability of the approach and validates our interleaved TMS/fMRI setup. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www3.interscience.wiley.com/cgi-bin/fulltext/121576647/PDFSTART Biologische Kybernetik Max-Planck-Gesellschaft en 10.1002/jmri.21611 mariusMMoisa rolfRPohmann LEwald thielscherAThielscher article ThielscherRW2008 Brain Stimulation 2008 7 1 3 275-276 Method: In 3 subjects, VEPs were reliably induced by a small checkerboard stimulus briefly presented in the parafoveal lower right quadrant (Fig. 1B). Subjects S1 and S2 had classical VEP patterns, in S3 the P100 was missing. A random quadrant of the checkerboard was shown at reduced contrast. Subjects had to identify and report it by a button-press. TMS was applied to the left occ. pole (MagVenture MagPro X100; MC-B70 coil). The best TMS timing and coil position were determined in pretests. The timing with the strongest suppression corresponded to the N80 (S1&S2) and the missing P100 (S3), respectively. We tested 3 conditions: Combined “TMS&visual” stimulation, “Visualonly” and “TMSonly”. An experimental run (∼4min) contained trials of all conditions in a randomized order. 5 TMS intensities were tested, ranging from phosphene threshold to the intensity evoking chance level performance (or maximally 85% of max. stimulator output; Fig.1A). The 5 intensities were tested in separate runs in a randomized order. Using several sessions, ∼120 trials were acquired for each condition at each intensity. EEG was recorded using a BrainAmp MR plus amplifier (Brain Products, Germany; 32 channels; impedances <5 kOhm) and analyzed using EEGLAB 6.01 (Delorme & Makeig, 2004). Pre-processing involved TMS artifact removal using polynomial interpolation, band-pass filtering (cutoff 0.1 & 50 Hz), baseline correction and eye blink rejection. The mean of the TMSonly trials was subtracted from the mean of the TMS&visual trials to determine the TMS effect on the VEPs. Analysis concentrated on a region-of-interest of 7 electrodes (Fig. 1C). Result: In S1 and S2, the P100 increased monotonically for the 3 lower TMS intensities (Fig. 1C&D) and leveled off for the 2 highest intensities, at which visual suppression occurred (Fig. 1A). In S3, the N150 increased for the first 4 intensities, and then decreased. Similar modulations occured for the N150 in S1 and S2 and the “P200” in S3 (data not shown). Conclusion: The VEP modulation patterns hint towards a saturation effect taking place when TMS is strong enough to induce robust suppression. Future work involves testing a further subject to confirm the modulation effects, and the systematic variation of the TMS SOA. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ Department Logothetis Department Bülthoff http://www.sciencedirect.com/science/article/pii/S1935861X08002696 10.1016/j.brs.2008.06.233 thielscherAThielscher areichenAReichenbach kevinKWhittingstall article 5529 Brain Stimulation 2008 7 1 3 283-284 Involvement of the left posterior parietal cortex (lPPC) in online motor control has been demonstrated in recent years using fMRI (Culham et al, 2006). However, the human homologue to macaque parietal reach region, or even more detailed functional anatomy of processes involved in motor control, is still controversial (lacoboni, 2006). The main challenge is the spatial co-localization of functions that are also involved in motor execution, e.g. attention, saccades, and motor planning (Astafiev et al, 2003). TMS offers the possibility to disentangle these functions due to its high temporal resolution, and can also discriminate necessary from co-activated brain areas. Desmurget et al (1999) showed that online correction for reaching to an altered target can be disturbed using TMS over the lPPC. In this study, we developed an fMRI localizer to assess lPPC sub-regions that are involved in online motor control. Subsequently, we tested these sites with event-related TMS. Using closed-loop reaching (with visual hand feedback) allows investigating the processes involved in body's effectors representation in addition to environment representation during goal-directed reaching, by introducing different visual perturbations. The fMRI localizer consists of blocks for fixation, saccades, and reaching with an MR-compatible joystick. Within the reaching blocks, different visual perturbations (including none) were randomized in a fast event-related design. The different perturbation conditions were contrasted against the unperturbed reaching to assess online-correction activation. Nine right-handed subjects were tested. On group level, different visual perturbations resulted in spatial different activation patterns in the lPPC. In addition, we observed pronounced inter-individual differences in activation. Maxima from the group analyses and the individuals own maxima were used as stimulation sites for the subsequent TMS study. Four of the subjects were tested so far using event-related TMS on target alteration. Despite huge inter-individual differences in BOLD activation, we could demonstrate a closer match of TMS effect localization with subject's individual activation than with group activation (fig. 1). This finding shows that TMS is capable of investigating sub-regions of the lPPC. Furthermore, it stresses the importance of individual analyses when investigating functions located there. The next step is to map the other visual perturbations. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://www.sciencedirect.com/science?_ob=MiamiImageURL&_cid=276827&_user=29041&_pii=S1935861X08001538&_check=y&_origin=&_coverDate=31-Jul-2008&view=c&wchp=dGLbVlS-zSkzS&md5=afc13540a9d1352eb4a46d9b24a64de2/1-s2.0-S1935861X08001538-main.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.brs.2008.06.117 areichenAReichenbach brescianiJ-PBresciani APeer hhbHHBülthoff thielscherAThielscher article 5180 Biological Cybernetics 2008 4 98 4 305-337 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.springerlink.com/content/f467952213622785/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1007/s00422-008-0211-7 thielscherAThielscher HNeumann article 5386 Nature Medicine 2008 4 14 4 459-465 Noninvasive imaging at the molecular level is an emerging field in biomedical research. This paper introduces a new technology synergizing two leading imaging methodologies: positron emission tomography (PET) and magnetic resonance imaging (MRI). Although the value of PET lies in its high-sensitivity tracking of biomarkers in vivo, it lacks resolving morphology. MRI has lower sensitivity, but produces high soft-tissue contrast and provides spectroscopic information and functional MRI (fMRI). We have developed a three-dimensional animal PET scanner that is built into a 7-T MRI. Our evaluations show that both modalities preserve their functionality, even when operated isochronously. With this combined imaging system, we simultaneously acquired functional and morphological PET-MRI data from living mice. PET-MRI provides a powerful tool for studying biology and pathology in preclinical research and has great potential for clinical applications. Combining fMRI and spectroscopy with PET paves the way for a new perspective in molecular imaging. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.nature.com/nm/journal/v14/n4/pdf/nm1700.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1038/nm1700 MSJudenhofer HFWehrl DFNewport CCatana SBSiegel MBecker thielscherAThielscher MKneilling MPLichy MEichner KKlingel GReischl SWidmaier MRöcken RENutt H-JMachulla kuludagKUludag SRCherry CDClaussen BJPichler article 4954 Neuroscience 2008 2 151 3 730-736 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T0F-4R8NBH1-6-1&_cdi=4861&_user=29041&_orig=search&_coverDate=02%2F06%2F2008&_sk=998489996&view=c&wchp=dGLbVtz-zSkWb&md5=ab1dc18c92c26fc81e7d421dccd2deaf&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuroscience.2007.11.040 thielscherAThielscher MKölle HNeumann MSpitzer GGrön article 4311 Journal of Computational Neuroscience 2007 6 22 3 255-282 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://springerlink.metapress.com/content/j8621351q28168l8/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1007/s10827-006-0011-9 thielscherAThielscher HNeumann article 4420 Journal of Neuroscience 2007 3 27 11 2908-2917 In the present study, we tested the hypothesis that brain activation would reflect perceptual choices. To probe this question, we used functional magnetic resonance imaging (fMRI) during a challenging fear–disgust, two-choice discrimination task. We investigated how moment-to-moment fluctuations in fMRI signals were correlated with perceptual choice by computing a choice probability index that quantified how well behavioral choice could be predicted by single-trial fMRI amplitude. Our analyses revealed that reporting a neutral face as "fearful" was associated with activation in a broad network of brain regions that process emotionally arousing stimuli, whereas reporting a neutral face as "disgusted" was associated with activation in a focused set of sites that included the putamen and anterior insula. Responses predictive of perceptual reports were not only observed at the group level but also at the single-subject level. Thus, voxel-by-voxel fluctuations in fMRI amplitude for an individual participant could be used to reliably predict the perceptual choice of individual trials for that subject. In addition to the investigation of choice, we also isolated the neural correlates of decision making per se by using reaction time as an index of decision processes. Overall, our findings revealed that brain responses dynamically shifted according to perceptual choices. In addition, the neural correlates of decision making involved at least the anterior cingulate cortex, middle frontal gyrus, and inferior frontal gyrus/insula, consistent with recent proposals that decisions may emerge from distributed processes. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.jneurosci.org/cgi/reprint/27/11/2908 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1523/JNEUROSCI.3024-06.2007 thielscherAThielscher LPessoa article 40 Clinical Neurophysiology 2001 2 112 2 250-258 Objectives: To evaluate the stimulation effectiveness of different magnetic stimulator devices with respect to pulse waveform and current direction in the motor cortex. Methods: In 8 normal subjects we determined motor thresholds of transcranial magnetic stimulation in a small hand muscle. We used focal figure-of-eight coils of 3 common stimulators (Dantec Magpro, Magstim 200 and Magstim Rapid) and systematically varied current direction (postero-anterior versus antero-posterior, perpendicular to the central sulcus) as well as pulse waveform (monophasic versus biphasic). The coil position was kept constant with a stereotactic positioning device. Results: Motor thresholds varied consistently with changing stimulus parameters, despite substantial interindividual variability. By normalizing the values with respect to the square root of the energy of the capacitors in the different stimulators, we found a homogeneous pattern of threshold variations. The normalized Magstim threshold values were consistently higher than the normalized Dantec thresholds by a factor of 1.3. For both stimulator types the monophasic pulse was more effective if the current passed the motor cortex in a postero-anterior direction rather than antero-posterior. In contrast, the biphasic pulse was weaker with the first upstroke in the postero-anterior direction. We calculated mean factors for transforming the intensity values of a particular configuration into that of another configuration by normalizing the different threshold values of each individual subject to his lowest threshold value. Conclusions: Our transformation factors allow us to compare stimulation intensities from studies using different devices and pulse forms. The effectiveness of stimulation as a function of waveform and current direction follows the same pattern as in a peripheral nerve preparation (J Physiol (Lond) 513 (1998) 571). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/S1388245700005137 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/S1388-2457(00)00513-7 kammerTKammer sbeckSBeck thielscherAThielscher ULaubis-Herrmann HTopka poster CornelsenHT2012 2012 6 Introduction: Regions in the posterior parietal cortex and the premotor cortex contribute to online control in reaching and grasping. Structural connectivity suggests the division of parieto-frontal networks into two neuronal circuits. The dorsomedial circuit connects the superior parietal occipital cortex (SPOC) and medial intraparietal sulcus (mIPS) with the dorsal part of the premotor cortex (PMd) (Tanne-Gariepy, Rouiller, & Boussaoud, 2002), and is associated with reaching. The dorsolateral circuit includes the aIPS, which is highly interconnected with the ventral part of the premotor cortex (PMv) (Tanne-Gariepy et al., 2002; Tomassini et al., 2007), and is associated with grasping. However, recent findings question a strict functional distinction between both circuits, but rather suggest that the functional connectivity between these circuits is influenced by the required amount of online control during reach-to-grasp movements (Grol et al., 2007). Here, we used a perturbation paradigm to clearly separate the fMRI activity reflecting online control from that of the planning phase. We tested the reaction to changes of target location, target size, or both at movement onset. In a preceding experiment, the amount of online control required for the correction of grasp and reach perturbations was matched. Methods: Sixteen participants were tested in a 3T scanner with their heads tilted and elevated to allow for a natural sight of the hand. Two target objects were mounted above the participant's hip. Participants had to grasp the illuminated target (unperturbed trials). When reaching was perturbed, the illumination of the object was extinguished and the other object was illuminated, thus changing the location of the target. When grasping was perturbed, the extent of target illumination changed, changing the size of the target. Reaction (RT) and movement times (MT) as well as eye and hand movements were recorded. Whole-brain functional images were collected (GR EPI with TR/TE = 2130/35ms; 3.0 x 3.0mm² in-plane resolution, 3.5mm slice thickness, 33 slices). Using a slow event-related design, eight experimental runs with 32 trials each were acquired per participant. Effector-specificity during the movement phase was tested in a two stage-approach: First, two sets of regions-of-interests (ROIs) were identified using the contrasts reaching perturbed > unperturbed and grasping perturbed > unperturbed, respectively, in combination with anatomical landmarks (Fig. 1). Using this procedure, the ROIs were optimally located to capture the activity increases due to one of the two perturbation types. Second, within the ROIs, we tested whether the activity for reaching perturbed and grasping perturbed differed significantly from each other. Conclusions: None of the areas involved in online control showed activation differences between perturbed reaching and perturbed grasping. These results support the suggestion that the aIPS and the SPOC are not strictly effector-specific organized. In contrast, we found that mIPS, mIPS2, and the right PMd show different activation patterns if the grip is corrected into a different target size, indicating that these cortical areas are influenced by the amount of required online control. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/OHBM-2012-Cornelsen.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler https://ww4.aievolution.com/hbm1201/index.cfm?do=abs.viewAbs&abs=6278 Beijing, China 18th Annual Meeting of the Organization for Human Brain Mapping (OHBM 2012) sonnenscheinSCornelsen MHimmelbach thielscherAThielscher poster OpitzWHTT2011_2 2011 6 17 The biophysics of transcranial magnetic stimulation (TMS) is not yet well understood. We characterize in detail the electric field induced in gray (GM) and white matter (WM), using a geometrically accurate model of an individual head combined with high-resolution diffusion weighted imaging (DWI). Use of finite element methods (FEM) allows determination of the impact of gyrus orientation and WM anisotropy on the field induced by a figure-8 coil. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/HBM-2011-Opitz.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Scheffler http://www.humanbrainmapping.org/i4a/pages/index.cfm?pageID=3419 Québec City, Canada 17th Annual Meeting of the Organization for Human Brain Mapping (HBM 2011) aopitzAOpitz mwindhoffMWindhoff RHeidemann RTurner thielscherAThielscher poster ReichenbachBBT2011 2011 6 940 fMRI and TMS studies have shown that visual and proprioceptive information for motor control are integrated in the posterior parietal cortex (PPC) (e.g. Culham and Valyear, 2006; Filimon et al., 2009; Reichenbach et al., 2010). When the head is moving in space during a goal-directed movement, vestibular signals have to be integrated into the motor processing as well. The neural correlates of these integration processes during motor control have not been investigated thus far. However, fMRI studies about vestibular stimulation have shown that the PPC is also processing vestibular information (Suzuki et al., 2001; Dieterich et al., 2003; Stephan et al., 2005). Furthermore, Seemungal et al. (2008) demonstrated that the administration of TMS over the PPC disturbs the perception of the position in space when the body is rotated. For the TMS study presented here, we used the behavioral paradigm of Bresciani et al. (2002) where subjects performed a goal-directed reaching task while suddenly being rotated. In order to assess the neural correlates of vestibular information processing for movement control, we probed with TMS the necessity of several sites on the PPC for this motor task. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/HBM-2011-Reichenbach.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department Scheffler http://www.humanbrainmapping.org/i4a/pages/index.cfm?pageID=3419 Québec City, Canada 17th Annual Meeting of the Organization for Human Brain Mapping (HBM 2011) areichenAReichenbach brescianiJ-PBresciani hhbHHBülthoff thielscherAThielscher poster 6847 2010 7 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://fens2010.neurosciences.asso.fr/pages/sub/SatellitesEvents.php Biologische Kybernetik Max-Planck-Gesellschaft Nijmegen, Netherlands FENS 2010 Satellite Symposium on Motor Control en areichenAReichenbach thielscherAThielscher APeer hhbHHBülthoff brescianiJ-PBresciani 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 6609 2010 6 16 8 WTh-PM 168 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Abstract-MW-HBM-2010_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.humanbrainmapping.org/files/2010MeetingFiles/OHBM%202010%20Abstract%20Book.pdf Biologische Kybernetik Max-Planck-Gesellschaft Barcelona, Spain 16th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2010) en mwindhoffMWindhoff thielscherAThielscher poster 6611 2010 6 4 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.fmrib.ox.ac.uk/misc_events/tms-school-page Biologische Kybernetik Max-Planck-Gesellschaft Oxford, UK Magstim/University of Oxford TMS Summer School en aopitzAOpitz mwindhoffMWindhoff areichenAReichenbach thielscherAThielscher poster 7076 2010 6 16 10 MT-PM 109 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ Research Group Noppeney http://www.humanbrainmapping.org/files/2010MeetingFiles/OHBM%202010%20Abstract%20Book.pdf Biologische Kybernetik Max-Planck-Gesellschaft Barcelona, Spain 16th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2010) en joanaleitaoJLeitão thielscherAThielscher sebastianwernerSWerner rolfRPohmann unoppeUNoppeney poster 6846 2010 6 16 1259 MT-AM 45 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://www.humanbrainmapping.org/files/2010MeetingFiles/OHBM%202010%20Abstract%20Book.pdf Biologische Kybernetik Max-Planck-Gesellschaft Barcelona, Spain 16th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2010) en areichenAReichenbach brescianiJ-PBresciani APeer hhbHHBülthoff thielscherAThielscher poster MoisaPST2010 2010 5 2010 1105 We have recently demonstrated the technical feasibility and the potential advantages of combining transcranial magnetic stimulation (TMS) with multi slice continuous arterial spin labeling (CASL) imaging (1). Here, we use this novel approach to assess the effects of repetitive TMS applied to the left dorsal premotor cortex (PMd) on rCBF (regional cerebral blood flow). Motivated by prior studies demonstrating that the effects of rTMS protocols depend on the activation state of the stimulated cortex (e.g., 2, 4), we compare the effects of stimulation during different motor states (i.e., at rest and during sequential finger tapping with the left hand [FT]). http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/ISMRM-2010-1105.PDF http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.ismrm.org/10/ Stockholm, Sweden ISMRM-ESMRMB Joint Annual Meeting 2010 mariusMMoisa rolfRPohmann HSiebner thielscherAThielscher poster 6053 NeuroImage 2009 7 47 Supplement 1 S63 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ Department Logothetis Department Bülthoff http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WNP-4X3PHYG-C5-1&_cdi=6968&_user=29041&_pii=S1053811909703131&_orig=search&_coverDate=07%2F31%2F2009&_sk=999529999.8998&view=c&wchp=dGLbVlb-zSkWz&md5=2470e848fa9c4374e77849be08a165d4&ie=/sdarticle. Biologische Kybernetik Max-Planck-Gesellschaft Melbourne, Australia 15th Annual Meeting of the Organization for Human Brain Mapping (HBM 2009) en 10.1016/S1053-8119(09)70313-1 thielscherAThielscher areichenAReichenbach kevinKWhittingstall poster 6051 NeuroImage 2009 7 47 Supplement 1 S170 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WNP-4X3PHYG-29K-1&_cdi=6968&_user=29041&_pii=S1053811909718373&_orig=search&_coverDate=07%2F31%2F2009&_sk=999529999.8998&view=c&wchp=dGLzVzz-zSkWz&md5=6840d2d050057afd95d23fcd95b1e3c9&ie=/sdarticle Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/S1053-8119(09)71837-3 mariusMMoisa kuludagKUludag rolfRPohmann thielscherAThielscher poster 5993 2009 7 7 A3-24 150 Involvement of the left posterior parietal cortex (lPPC) in online motor control has been demonstrated using mainly functional magnetic resonance imaging (fMRI, for review see Culham et al, 2006). However, the human homologue to the macaque parietal reach region, or even more detailed functional anatomy of processes involved in motor control, is still controversial (Iacoboni, 2006). One challenge is the spatial co-localization of functions that are also involved in motor execution, e.g. saccades, and motor planning (Astafiev et al, 2003). Because of its high temporal resolution, transcranial magnetic stimulation (TMS) offers the possibility to disentangle these functions. Additionally, it allows to discriminate necessary from co-activated brain areas. Desmurget et al (1999) showed that the ability to react online to a change in visual target position when reaching for it can be disturbed by applying TMS over the lPPC. The goal of the present study was to identify sub-regions in the PPC contributing to the integration of visual information during online control of reaching. A reach-to-target paradigm with two perturbations induced correction upon target and body-related visual information, respectively: Displacement of the visual target and displacement of the visual feedback of hand position. We combined an fMRI localizer task with subsequent TMS experiments. The fMRI localizer gave an overview over the involved areas and enabled the selection of TMS stimulation sites. Inter-individual differences in (functional) neuroanatomy, being apparent in the human PPC (Grefkes and Fink, 2005), were thereby taken into account. The subsequent TMS experiments showed that regions from the anterior part of the intraparietal sulcus into the supramarginal gyrus are crucial for processing of target and bodyrelated visual information during online control of reaching. The TMS effects were spatially selective and correlated with the fMRI activation, thus demonstrating a good spatial resolution of the offline combination of TMS with fMRI. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/PMC-2009-Reichenbach.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ Biologische Kybernetik Max-Planck-Gesellschaft Marseille, France 7th Edition of Progress in Motor Control (PMC 2009) en areichenAReichenbach brescianiJ-PBresciani APeer hhbHHBülthoff thielscherAThielscher poster 5994 NeuroImage 2009 7 47 Supplement 1 S170 Introduction Involvement of the left posterior parietal cortex (lPPC) in online motor control has been demonstrated in recent years using fMRI (Culham et al, 2006). However, the human homologue to the macaque parietal reach region, or even more detailed functional anatomy of processes involved in motor control, is still controversial (Iacoboni, 2006). The main challenge is the spatial co-localization of functions that are also involved in motor execution, e.g. saccades, and motor planning (Astafiev et al, 2003). TMS offers the possibility to disentangle these functions due to its high temporal resolution, and can discriminate necessary from co-activated brain areas. Desmurget et al (1999) showed that online correction for reaching to an altered target can be disturbed using TMS over the lPPC. Here, we test sub-regions of the lPPC for necessity in online correction to different visual perturbations. Methods Nine healthy, right-handed participants performed closed-loop (i.e., with visual feedback of the hand) reach-to-target tasks with different perturbation paradigms: Displacement of the visual target or displacement of the visual hand feedback, which allowed us to investigate the processes involved in body's effectors representation and the processes involved in representation of the environment, respectively. First, the participants were tested with an fMRI localizer task to assess putative lPPC sub-regions that are involved in online motor control. The fMRI localizer consisted of blocks for fixation, saccades, and reaching with an MR-compatible joystick. Within the reaching blocks, the visual perturbations (including none) were randomized in a fast event-related design. The different perturbation conditions were contrasted against the unperturbed reaching to assess activation related to online-correction, masked with general reaching activation. Maxima from the group analyses, individual's own maxima, and control sites were used as stimulation sites for subsequent event-related TMS studies. The TMS experiments were conducted in a VR environment with a robot arm to enable naturalistic but highly controllable conditions. Results On the group level, we found different peak fMRI activations in the lPPC for different visual perturbations (Figure 1). Additionally, most subjects had strong individual peak fMRI activations on sites without group activation (Figure 2). The perturbing effect of TMS for corrections to a visual target perturbation is correlated with the strength of the fMRI activations (Figure 3), with effects on sites of group fMRI activation, additional effects on sites of individual's fMRI activation, but none on control sites (Figure 4). The perturbing effect of TMS for corrections to a visual hand perturbation is concentrated at the single group fMRI maximum. Conclusions Widespread areas in the lPPC are crucial for processing of visual target information needed for online control of movements. These areas include SMG in addition to anterior IPS and SPL. The area necessary for visual hand information processing is a part of the areas needed for visual target processing. Planning TMS stimulation sites based on individual fMRI activations is a more successful approach than planning them based on group fMRI activation, which is still better than planning without (f)MRI. The TMS effect is spatially selective, thus demonstrating a good spatial resolution of the method. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ Biologische Kybernetik Max-Planck-Gesellschaft San Francisco, CA, USA 15th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2009) en 10.1016/S1053-8119(09)71835-X areichenAReichenbach thielscherAThielscher APeer hhbHHBülthoff brescianiJ-PBresciani poster 5319 Brain Stimulation 2008 7 1 3 290-291 CASL (continuous arterial spin labeling) offers the possibility of measuring simultaneously rCBF (regional cerebral blood flow) as well as the BOLD effect. The aim of this study is to demonstrate the technical feasibility to combine TMS with multi slice CASL imaging. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science?_ob=PdfDownloadURL&_uoikey=B8JBG-4T8JVVB-5C&_tockey=%23toc%2343558%232008%23999989996%23696438%23FLA%23&_orig=search&_acct=C000003178&_version=1&_userid=29041&md5=fd0631b85d11cc4c84e26de4420ab78c Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.brs.2008.06.136 mariusMMoisa rolfRPohmann kuludagKUludag thielscherAThielscher poster 5280 2008 7 9 108 176 When reaching for a target, the information provided by different sensory channels is continuously processed to supervise the ongoing movement. If a discrepancy between predicted end-point of movement and target location is detected, the arm trajectory is modulated to preserve reaching accuracy. Desmurget et al. (1999) showed that the left posterior parietal cortex (lPPC) is crucial for this online control when the visual target is displaced. We investigate further the localization of involved brain areas in the lPPC and expand the paradigm to other visual and proprioceptive perturbations (visual hand feedback displacement and force impulse application to the reaching arm). An fMRI study served as localizer task. All subjects showed strong activation in the lPPC when correcting for any visual perturbation. Using event-related TMS, we subsequently tested the site of strongest fMRI activation on the lPPC and some adjacent control sites. The goal was to disrupt online corrections occurring with a target displacement. Despite huge inter-individual differences in the location of the strongest BOLD activation, we could demonstrate spatial localized TMS effects in congruence with the site of each participant’s individual fMRI activation in the lPPC. The next goal is to find the dedicated cortical sites for the other perturbations. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://imrf.mcmaster.ca/IMRF/2008/pdf/FullProgramIMRF08.pdf Biologische Kybernetik Max-Planck-Gesellschaft 9th Hamburg, Germany 9th International Multisensory Research Forum (IMRF 2008) en areichenAReichenbach thielscherAThielscher APeer hhbHHBülthoff brescianiJ-PPBresciani poster 5279 NeuroImage 2008 6 41 Supplement 1 S94 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://www.humanbrainmapping.org/i4a/pages/index.cfm?pageid=3299 Biologische Kybernetik Max-Planck-Gesellschaft Melbourne, Australia 14th Annual Meeting of the Organization for Human Brain Mapping (HBM 2008) en 10.1016/j.neuroimage.2008.04.008 areichenAReichenbach brescianiJ-PBresciani APeer hhbHHBülthoff thielscherAThielscher poster 5318 2008 5 16 2428 Interleaved TMS/fMRI is a promising technique to study connectivity between brain areas. An important practical challenge is the positioning of the coil inside the MRI scanner. We describe a novel method that combines software and hardware for accurate TMS coil placement and report pilot results on its usage studying the motor system. In a phantom study, the accuracy of the method was demonstrated to be within the range previously reported for normal neuronavigation systems. The results of the motor cortex study are in concordance with prior findings, demonstrating the viability of our positioning method and our overall interleaved TMS/fMRI setup. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/ISMRM-2008-02428.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.ismrm.org/08/ Biologische Kybernetik Max-Planck-Gesellschaft Toronto, Canada 16th Scientific Meeting and Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2008) en mariusMMoisa rolfRPohmann KUgurbil thielscherAThielscher poster 4780 2007 10 53-54 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://www.esf.org/conferences/07226 Biologische Kybernetik Max-Planck-Gesellschaft Sant Feliu de Guixols, Spain ESF-EMBO Symposium on Three Dimensional Sensory and Motor Space: Perceptual Consequences of Motor Action en areichenAReichenbach thielscherAThielscher APeer hhbHHBülthoff brescianiJ-PBresciani poster 4578 2007 7 10 90 In Transcranial Magnetic Stimulation (TMS), strong magnetic pulses delivered by a coil placed over the subject’s head are used to induce neural activity in a focal area of the brain. TMS can be used to demonstrate a causal relationship between behavior and the neural processing in a brain structure of interest by showing that a subject’s task performance is diminished during TMS stimulation of that structure (i.e., the “virtual lesion” approach [1]). We addressed two questions in the current study: 1) How well does the position of the maximal TMS effect coincide with the brain activation pattern observed during the task using other neuroimaging techniques such as fMRI or PET? 2)Which visual area is most critical for conscious perception of a visual stimulus, i.e. which visual area has to be disturbed after stimulus presentation to diminish the recognition performance significantly? (“visual suppression” effect [2,3]). In all subjects, the spatial pattern of the TMS effect was smooth and the coil positions at which the maximal suppression occurred were located next to each other. This indicates that the TMS target was a single continuous brain structure and not, e.g. two or more separate sub-areas. The Center of Gravity (CoG) of the TMS map was consistently positioned over the inferior part of the superior occipital gyrus. As expected, the fMRI activation pattern was rather extended and covered several visual areas. The TMS CoG was consistently located over the medial-inferior part of the fMRI activation. Visual mapping [4] delineated the TMS CoG being significantly closer to the CoG of V2 than to any other visual area. Mean deviation of TMS CoG from V2 CoG obtained with fMRI was 5.1mm (SE 0.6mm, n=7), showing a good spatial congruence between these two neuroimaging techniques. Several control studies were performed to test for possible involvement of other visual areas. The findings suggest that V2 and not primary visual cortex V1 is the brain area primarily targeted in visual suppression. In consequence, our data does not support the special role of V1 in conscious visual perception as previously suggested by several authors (for review see [5]). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://twk.tuebingen.mpg.de/twk07/abstract.php?_load_id=reichenbach01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 10th Tübinger Wahrnehmungskonferenz (TWK 2007) en areichenAReichenbach thielscherAThielscher KUgurbil kuludagKUludag poster 4526 NeuroImage 2007 6 36 Supplement 1 S86 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science/article/pii/S1053811907002789 Biologische Kybernetik Max-Planck-Gesellschaft Organization for Human Brain Mapping Chicago, IL, USA 13th Annual Meeting of the Organization for Human Brain Mapping (HBM 2007) en 10.1016/j.neuroimage.2007.03.045 thielscherAThielscher areichenAReichenbach KUgurbil kuludagKUludag poster 4495 2007 5 2007 2023 400 Transcranial Magnetic Stimulation can interfere with the neural processing in a brain area-of-interest. How well the spatial pattern of TMS interference coincides with the activation pattern observed in fMRI was evaluated. The coil position at which TMS suppressed the perception of a visual stimulus was determined and compared with the stimulus-related BOLD activation. The TMS effect consistently occurred over a specific subpart of the fMRI activation. While fMRI is capable of characterizing the general pattern of brain areas activated in a certain task, TMS has the potential to specifically localize those areas being most critical for the task. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.ismrm.org/07/ Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany 2007 Joint Annual Meeting ISMRM-ESMRMB en thielscherAThielscher areichenAReichenbach KUgurbil kuludagKUludag poster PadmalaTP2006 2006 10 36 368.1 Functional MRI data are typically analyzed in a subtractive-univariate fashion. In the present study, we utilized machine learning algorithms to “decode” brain states during the viewing of faces with emotional expressions. Subjects (n = 19) performed a two-choice task in which they decided if a briefly presented face (80 ms) displayed either a fearful or a disgusted expression while fMRI data were acquired (1.5T). Trials occurred every 15 s in a slow event-related design. Graded, computer-morphed levels of the emotional expressions were obtained by morphing neutral and fearful expressions and, separately, neutral and disgusted expressions. The final graded-stimulus series contained 100%, 75% and 37% fearful faces, neutral face, 37%, 75% and 100% disgusted faces. When predicting the stimulus viewed by the participant, we considered voxels from five ROIs that exhibited strong task activation: middle occipital gyrus, fusiform gyrus, IPS, anterior insula, and inferior frontal sulcus. For prediction, we employed standard linear Support Vector Machines (SVM). When the SVM was trained on 100% stimuli, prediction accuracy (i.e., correctly classifying the stimulus as fearful or disgusted) averaged 76.4% correct (assessed via k-fold cross validation) and exceeded 85% for 8 subjects. Next, we tested how well a machine trained on the 100% stimuli would perform with graded stimuli (in such cases, the SVM was never trained with graded stimuli). For 75% graded stimuli, classification accuracy was 65.8%; for 37% graded stimuli, it was 59.3%. In all cases, prediction accuracy was best when a small subset of voxels (7 on average) was used. Our results show that we can employ the distributed pattern of single-trial activation to predict the stimulus viewed by the participant. In addition, training on 100% stimuli could be used to predict the perception of graded stimuli, demonstrating that the SVM learned features that generalized across perceptual conditions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sfn.org/index.aspx?pagename=abstracts_ampublications Atlanta, GA, USA 36th Annual Meeting of the Society for Neuroscience (Neuroscience 2006) SPadmala thielscherAThielscher LPessoa poster 4389 Neuroimage 2006 6 31 Supplement 1 S47 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science/article/pii/S1053811906004575 Biologische Kybernetik Max-Planck-Gesellschaft Firenze, Italy 12th Annual Meeting of the Organization for Human Brain Mapping (HBM 2006) en 10.1016/j.neuroimage.2006.04.176 ssadaghiSSadaghiani thielscherAThielscher KUgurbil kuludagKUludag poster 4313 Neuroimage 2006 6 31 Supplement 1 S176 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://www.sciencedirect.com/science/article/pii/S1053811906004575 Biologische Kybernetik Max-Planck-Gesellschaft Organization for Human Brain Mapping Firenze, Italy 12th Annual Meeting of the Organization for Human Brain Mapping (HBM 2006) en 10.1016/j.neuroimage.2006.04.176 thielscherAThielscher LPessoa poster ThielscherK2003 2003 6 29 1168 We report a novel method to determine the site and size of stimulated cortical area in TMS. Applied to the motor cortex, it allows to determine the likely cortical representation of muscles. Up to now, the most common procedure for this is motor mapping. In motor mapping, the obtained two-dimensional distribution of coil positions with associated muscle responses is used to calculate a center of gravity on the skull. However, classical mapping does not allow to determine the exact stimulation site on the cortex and only rough estimates of its size are possible. Our method combines physiological measurements with a physical model used to predict the electric field induced by the TMScoi l to overcome these limitations. In four subjects motor responses in a small hand muscle were mapped with 9 - 13 stimulation sites at the head perpendicular to the central sulcus in order to keep the induced current direction constant in a given cortical region of interest. Input-output functions from these head locations were used to determine stimulator intensities that elicit half-maximal muscle responses. Based on these stimulator intensities the field distribution on the individual cortical surface was calculated as rendered from anatomical MR data. The region on the cortical surface in which the different stimulation sites produced the same electric field strength (minimal variance 4.2 ± 0.8 %. ) was determined as the most likely stimulation site on the cortex. In all subjects, it was located at the lateral part of the hand knob in the motor cortex. Comparisons of model calculations with the solutions obtained in this manner reveal that the stimulated cortex area innervating the target muscle is substantially smaller than the size of the electric field induced by the coil. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ Department Bülthoff http://www.neuro.uni-goettingen.de/nbc.php?sel=archiv Göttingen, Germany 29th Göttingen Neurobiology Conference thielscherAThielscher kammerTKammer poster 963 2001 11 31 401.14 Stereotactic positioning devices allow to exactly navigate the position of a TMS coil with respect to the individual cortical architecture. However, the exact stimulation site and the size of the neuronal pool stimulated still remain unknown. We used a common spherical model to predict the cortical stimulation site in the motor system. In 4 subjects motor responses were registered in a small hand muscle. A stereotactic positioning system allowed to measure continually the position of the figure-of-eight coil with respect to the individual cortical anatomy visualized in an anatomical 3d MRI scan. The coil was oriented perpendicular to the central sulcus and a hot spot was determined. Then motor responses were measured at several stimulation sites from threshold levels up to maximal responses, increasing stimulus intensity in steps of 10% (input-output function). The stimulation sites were placed in a line perpendicular to the central sulcus. With maximal stimulation intensity motor responses were obtained about 5 cm apart from the hot spot. For each stimulation site a sigmoidal function was fitted to the input-output data and the stimulation intensity for half-maximal motor responses was calculated. The distribution of the electric field strength was calculated on the cortical surface for each site using the spherical model. Finally, the region on the cortical surface was calculated where all different stimulation sites produced the same electric field strength (variance < 7%). In all subjects that region was found within the hand knob of the precentral gyrus. Using the field model a prediction of the effective field strength is possible. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sfn.org/index.aspx?pagename=abstracts_ampublications Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 31st Annual Meeting of the Society for Neuroscience (Neuroscience 2001) kammerTKammer thielscherAThielscher miscellaneous 5328 Jahrbuch der Max-Planck-Gesellschaft 2006 2007 337-341 In the last two decades, the development of functional magnetic resonance imaging (fMRI) substantially contributed to the progress of human cognitive neuroscience. Because fMRI assesses neuronal activity indirectly, only limited causal statements about brain processes can be made. In the following, it is shown exemplarily by combining fMRI and transcranial magnetic stimulation (TMS) how this limitation can be overcome. Thus, multimodal brain imaging methods offer new opportunities for the exploration of the human brain. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Jahrbuch2007-Thielscher_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department MRZ http://cms.mpg.de/mpg-export/mpg/website/bilderBerichteDokumente/dokumentation/jahrbuch/2007/biologische_kybernetik/forschungsSchwerpunkt/index.html Biologische Kybernetik Max-Planck-Gesellschaft de thielscherAThielscher kuludagKUludag KUgurbil