This file was created by the Typo3 extension sevenpack version 0.7.14 --- Timezone: CEST Creation date: 2013-05-22 Creation time: 23-24-39 --- Number of references 16 article 2419 Neural Computation 2004 11 16 11 2245-2260 Tangential neurons in the fly brain are sensitive to the typical optic flow patterns generated during egomotion. In this study, we examine whether a simplified linear model based on the organization principles in tangential neurons can be used to estimate egomotion from the optic flow. We present a theory for the construction of an estimator consisting of a linear combination of optic flow vectors that incorporates prior knowledge both about the distance distribution of the environment, and about the noise and egomotion statistics of the sensor. The estimator is tested on a gantry carrying an omnidirectional vision sensor. The experiments show that the proposed approach leads to accurate and robust estimates of rotation rates, whereas translation estimates are of reasonable quality, albeit less reliable. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf2419.pdf http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/ps2419.ps http://www.kyb.tuebingen.mpg.de Department Schölkopf http://www.mitpressjournals.org/doi/pdf/10.1162/0899766041941899 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1162/0899766041941899 mofMOFranz JSChahl hkrappHGKrapp article 43 Journal of Neurophysiology 2001 85 724-734 Integrating binocular motion information tunes wide-field direction-selective neurons in the fly optic lobe to respond preferentially to specific optic flow fields. This is shown by measuring the local preferred directions (LPDs) and local motion sensitivities (LMSs) at many positions within the receptive fields of three types of anatomically identifiable lobula plate tangential neurons: the three horizontal system (HS) neurons, the two centrifugal horizontal (CH) neurons, and three heterolateral connecting elements. The latter impart to two of the HS and to both CH neurons a sensitivity to motion from the contralateral visual field. Thus in two HS neurons and both CH neurons, the response field comprises part of the ipsi- and contralateral visual hemispheres. The distributions of LPDs within the binocular response fields of each neuron show marked similarities to the optic flow fields created by particular types of self-movements of the fly. Based on the characteristic distributions of local preferred directions and motion sensitivities within the response fields, the functional role of the respective neurons in the context of behaviorally relevant processing of visual wide-field motion is discussed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz http://jn.physiology.org/cgi/reprint/85/2/724.pdf Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp hbgRHengstenberg MEgelhaaf article 81 Biological Cybernetics 2000 8 83 3 185-197 The receptive field organization of a class of visual interneurons in the fly brain (vertical system, or VS neurons) shows a striking similarity to certain self-motion-induced optic flow fields. The present study compares the measured motion sensitivities of the VS neurons (Krapp et al. 1998) to a matched filter model for optic flow fields generated by rotation or translation. The model minimizes the variance of the filter output caused by noise and distance variability between different scenes. To that end, prior knowledge about distance and self-motion statistics is incorporated in the form of a “world model”. We show that a special case of the matched filter model is able to predict the local motion sensitivities observed in some VS neurons. This suggests that their receptive field organization enables the VS neurons to maintain a consistent output when the same type of self-motion occurs in different situations. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf81.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.springerlink.com/content/872k8k3yb0teaj9k/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/s004220000163 mofMOFranz hkrappHGKrapp article 241 Journal of Neurophysiology 1998 79 1902-1917 The third visual neuropil (lobula plate) of the blowfly Calliphora erythrocephala is a center for processing motion information. It contains, among others, 10 individually identifiable "vertical system" (VS) neurons responding to visual wide-field motions of arbitrary patterns. We demonstrate that each VS neuron is tuned to sense a particular aspect of optic flow that is generated during self-motion. Thus the VS neurons in the fly supply visual information for the control of head orientation, body posture, and flight steering. To reveal the functional organization of the receptive fields of the 10 VS neurons, we determined with a new method the distributions of local motion sensitivities and local preferred directions at 52 positions in the fly's visual field. Each neuron was identified by intracellular staining with Lucifer yellow and three-dimensional reconstructions from 10-µm serial sections. Thereby the receptive-field organization of each recorded neuron could be correlated with the location and extent of its dendritic arborization in the retinotopically organized neuropil of the lobula plate. The response fields of the VS neurons, i.e., the distributions of local preferred directions and local motion sensitivities, are not uniform but resemble rotatory optic flow fields that would be induced by the fly during rotations around various horizontal axes. Theoretical considerations and quantitative analyses of the data, which will be presented in a subsequent paper, show that VS neurons are highly specialized neural filters for optic flow processing and thus for the visual sensation of self-motions in the fly. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz http://jn.physiology.org/cgi/reprint/79/4/1902.pdf Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp bhbgBHengstenberg hbgRHengstenberg article 367 Vision Research 1997 37 225-234 We present a method to determine, within a few seconds, the local preferred direction (LPD) and local motion sensitivity (LMS) in small patches of the receptive fields of wide-held motion-sensitive neurons. This allows us to map, even during intracellular recordings, the distribution of LPD and LMS over the huge receptive fields of neurons sensing self-motions of the animal. Comparisons of the response field of a given neuron with the optic flow fields caused by different movements in space, allows us to specify the particular motion of the animal sensed by that neuron. Copyright (C) 1996 Elsevier Science Ltd. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T0W-3RBJ1C3-6-K&_cdi=4873&_orig=browse&_coverDate=11%2F29%2F1996&_sk=999629997&view=c&wchp=dGLbVtb-lSztz&_acct=C000003178&_version=1&_userid=29041&md5=5cddbec0e0451cbeeb7cd54eae7be3e6&ie=f.pdf Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp hbgRHengstenberg article 525 Nature 1996 384 463-466 Humans, animals and some mobile robots use visual motion cues for object detection and navigation in structured surroundings (1-4). Motion is commonly sensed by large arrays of small field movement detectors, each preferring motion in a particular direction (5, 6). Self-motion generates distinct 'optic flow fields' in the eyes that depend on the type and direction of the momentary locomotion (rotation, translation) (7). To investigate how the optic flow is processed at the neuronal level, we recorded intracellularly from identified interneurons in the third visual neuropile of the blowfly (8). The distribution of local motion tuning over their huge receptive fields was mapped in detail. The global structure of the resulting 'motion response fields' is remarkably similar to optic flow fields. Thus, the organization of the receptive fields of the so-called VS neurons (9,10) strongly suggests that each of these neurons specifically extracts the rotatory component of the optic flow around a particular horizontal axis. Other neurons are probably adapted to extract translatory flow components. This study shows how complex visual discrimination can be achieved by task-oriented preprocessing in single neurons. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf525.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp hbgRHengstenberg inbook 1235 2001 143-168 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Springer, Berlin Biologische Kybernetik Max-Planck-Gesellschaft H-JDahmen mofMOFranz hkrappHGKrapp inbook 342 1998 2 53-70 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf342.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz C.Taddei-Ferretti World Scientific Publishers

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Biologische Kybernetik Max-Planck-Gesellschaft hbgRHengstenberg hkrappHGKrapp bhbgBHengstenberg techreport 1529 1998 6 61 We present a theory for the construction of an optimal matched filter for self-motion induced optic flow fields. The matched filter extracts local flow components along a set of pre-defined directions and weights them according to an optimization principle which minimizes the difference between estimated and real egomotion parameters. In contrast to previous approaches, prior knowledge about distance and translation statistics is incorporated in the form of a "world model". Simulations indicate that the matched filter model yields reliable self-motion estimates. A comparison of the weight distribution used in the model with the local motion sensitivities of individual and small groups of interneurons in the fly visual system shows a close correspondence. This suggests that these so-called tangential neurons are tuned to optic flow fields induced by rotation or translation along a particular axis. They seem to weight the local optic flow according to the contribution of input noise and the expected variability of the translatory flow component. Their local preferred directions and motion sensitivities can be interpreted as an adaptation to the processing requirements of estimating self-motion from the optic flow. This technical report has also been <a href="/main/publication.php?machwas=view_e&edit_lfnr=81">published elsewhere</a> http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics, Tübingen mofMOFranz hkrappHGKrapp poster 276 1998 5 26 419 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf276.pdf http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/ps276.ps http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 26th Göttingen Neurobiology Conference mofMOFranz hbgRHengstenberg hkrappHGKrapp poster 574 Brain and Evolution, Vol. II, (Eds.) N. Elsner, H.U. Schnitzler. Thieme, Stuttgart 1996 1996 349 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf574.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft hbgRHengstenberg hkrappHGKrapp poster 1303 1995 9 4 255 The control of locomotion in a given environment requires information about instantaneous self-motion. Visually oriented animals, including man, may gain such information by analyzing the momentary optic flow pattern generated over both eyes during relative movement between animal and environment. Optic flow patterns can be described by vector fields where each single vector indicates the direction and velocity of the local relative movement at a certain position within the visual field. An optic flow pattern depends upon a set of motion parameters, namely (i) the direction of gaze and (ii) the rotatory and (iii) translatory components of self-motion. The translatory flow vectors also depend an the distance between visual objects and the eyes. Therefore, optic flow fields contain valuable information about the 3D-layout of the surroundings and instantaneous self-motion (Koenderink and van Doorn, 1987). About 50 motion-sensitive, wide-field interneurons which are assumed to be' involved in locomotor control are located in the third visual neuropil (lobula plate) of the blowfly's (Calliphora erythrocephala) visual system (Hausen, 1993). The output of many direction-specific movement detectors (EMDS) with small receptive fields are spatially integrated in a retinotopic manner an the dendrites of these interneurons. Are such interneurons adapted to sense specific aspects of the momentary optic flow field? To address this question, we investigated the receptive field organization of 10 identifiable interneurons of the so called vertical-system (VS; Hengstenberg, 1982) in great detail. We recorded intracellularly from the VS-neurons to determine the spatial distribution of local preferred directions and motion sensitivities at 52 positions spaced equally over the ipsilateral visual hemisphere (for method see: Menzel and Hengstenberg, 1991; Krapp and Hengstenberg 1992). The resulting response fields of the VS-neurons (about 90 recordings) show striking similarities to optic flow fields generated by specific motions in space (Krapp and Hengstenberg, 1994). By applying an iterative least square formalism (Koenderink and van Doorn, 1987) to the response fields we calculated the optimal self-motion parameters (translatory and rotatory component) for each VS-neuron. These parameters describe an optic flow field that best fits the respective measured response field. To find out whether the VS-neurons are functionally tuned more to the translatory or to the rotatory component of self-motion we systematically varied the optimal motion parameters. The error between the measured response field and the calculated optic flow field increases if both the translatory and the rotatory component deviate from the optimal motion parameters. The increase in the error is almost the same if only the rotatory component is varied. In contrast, if the translatory component is varied and the rotatory component is kept optimal the increase in the error is considerably smaller. The analysis of the response fields of the VS-neurons leads to the following conclusion: the VS-neurons are functionally tuned to sense rotations around different horizontally aligned body axes. The neurons VS1-VS3 are optimized to sense optic flow fields generated during nose-up pitch. VS4-VS7 are filter neurons for counterclockwise roll and VS8-VS10 are adapted to rotations around an axis that lies between the pitch and roll axes. Thus, the signals of the VS-neurons could contribute directly to visual flight control and gaze stabilization. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1303.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft Cambridge, UK 4th International Congress of Neuroethology hkrappHGKrapp hbgRHengstenberg poster 1301 1995 404 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1301.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp hbgRHengstenberg poster 515 1994 453 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf515.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp bhbgBHengstenberg hbgRHengstenberg poster 1297 1993 357 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1297.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp hbgRHengstenberg poster 1294 1992 306 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1294.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft hkrappHGKrapp hbgRHengstenberg