A Neural Model of Contour Integration in the Primary Visual Cortex

Experimental observations suggest that contour integration may take place in V1. However, there has yet to be a model of contour integration that uses only known V1 elements, operations, and connection patterns.This article introduces such a model, using orient ation selective cells, local cortical circuits, and horizontal intracortical connections. The model is composed of recurrently connected excitatory neurons and inhibitory interneurons, receiving visual input via oriented receptive fields resembling those found in primary visual cortex. Intracortical interactions modify initial activity patterns from input, selectively amplifying the activities of edges that form smooth contours in the image. The neural activities produced by such interactions are oscillatory and edge segments within a contour oscillate in synchrony. It is shown analytically and empirically that the extent of contour enhancement and neural synchrony increases with the smoothness, length, and closure of contours, as observed in experiments on some of these phenomena. In addition, the model incorporates a feedback mechanism that allows higher visual centers selectively to enhance or suppress sensitivities to given contours, effectively segmenting one from another. The model makes the testable prediction that the horizontal cortical connections are more likely to target excitatory (or inhibitory) cells when the two linked cells have their preferred orientation aligned with (or orthogonal to) their relative receptive field center displacements.

[1]  D. Ts'o,et al.  The organization of chromatic and spatial interactions in the primate striate cortex , 1988, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[2]  Pierre Baldi,et al.  Computing with Arrays of Coupled Oscillators: An Application to Preattentive Texture Discrimination , 1990, Neural Computation.

[3]  U. Polat,et al.  The architecture of perceptual spatial interactions , 1994, Vision Research.

[4]  E. Todorov,et al.  Vector-space integration of local and long-range information in visual cortex 7 , 1995 .

[5]  R. Eckhorn,et al.  Oscillatory and non-oscillatory synchronizations in the visual cortex and their possible roles in associations of visual features. , 1994, Progress in brain research.

[6]  P A Salin,et al.  Corticocortical connections in the visual system: structure and function. , 1995, Physiological reviews.

[7]  G. Shepherd The Synaptic Organization of the Brain , 1979 .

[8]  Ennio Mingolla,et al.  Neural dynamics of perceptual grouping: Textures, boundaries, and emergent segmentations , 1985 .

[9]  Victor A. F. Lamme,et al.  Contextual Modulation in Primary Visual Cortex , 1996, The Journal of Neuroscience.

[10]  Leif H. Finkel,et al.  Salient Contour Extraction by Temporal Binding in a Cortically-based Network , 1996, NIPS.

[11]  A. Grinvald,et al.  Relationship between intrinsic connections and functional architecture revealed by optical imaging and in vivo targeted biocytin injections in primate striate cortex. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[12]  Peter König,et al.  Stimulus-Dependent Assembly Formation of Oscillatory Responses: I. Synchronization , 1991, Neural Computation.

[13]  L. Maffei,et al.  The unresponsive regions of visual cortical receptive fields , 1976, Vision Research.

[14]  J. Allman,et al.  Stimulus specific responses from beyond the classical receptive field: neurophysiological mechanisms for local-global comparisons in visual neurons. , 1985, Annual review of neuroscience.

[15]  Lance R. Williams,et al.  Local Parallel Computation of Stochastic Completion Fields , 1997, Neural Computation.

[16]  I Kovács,et al.  A closed curve is much more than an incomplete one: effect of closure in figure-ground segmentation. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[17]  Shimon Ullman,et al.  Structural Saliency: The Detection Of Globally Salient Structures using A Locally Connected Network , 1988, [1988 Proceedings] Second International Conference on Computer Vision.

[18]  J. Lund,et al.  Intrinsic laminar lattice connections in primate visual cortex , 1983, The Journal of comparative neurology.

[19]  Rüdiger von der Heydt,et al.  A computational model of neural contour processing: Figure-ground segregation and illusory contours , 1993, 1993 (4th) International Conference on Computer Vision.

[20]  E. White Cortical Circuits , 1989, Birkhäuser Boston.

[21]  R. von der Heydt,et al.  Illusory contours and cortical neuron responses. , 1984, Science.

[22]  C. Gilbert,et al.  Improvement in visual sensitivity by changes in local context: Parallel studies in human observers and in V1 of alert monkeys , 1995, Neuron.

[23]  R. Weale Vision. A Computational Investigation Into the Human Representation and Processing of Visual Information. David Marr , 1983 .

[24]  D. V. van Essen,et al.  Neuronal responses to static texture patterns in area V1 of the alert macaque monkey. , 1992, Journal of neurophysiology.

[25]  R. Blake,et al.  Grouping visual features during binocular rivalry , 1999, Vision Research.

[26]  Gérard G. Medioni,et al.  Inferring global perceptual contours from local features , 1993, Proceedings of IEEE Conference on Computer Vision and Pattern Recognition.

[27]  T. Wiesel,et al.  Columnar specificity of intrinsic horizontal and corticocortical connections in cat visual cortex , 1989, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[28]  Sompolinsky,et al.  Cooperative dynamics in visual processing. , 1991, Physical review. A, Atomic, molecular, and optical physics.

[29]  D. Fitzpatrick The functional organization of local circuits in visual cortex: insights from the study of tree shrew striate cortex. , 1996, Cerebral cortex.

[30]  D. Hubel,et al.  Receptive fields, binocular interaction and functional architecture in the cat's visual cortex , 1962, The Journal of physiology.

[31]  D. Heeger Normalization of cell responses in cat striate cortex , 1992, Visual Neuroscience.

[32]  C. Gilbert,et al.  Synaptic physiology of horizontal connections in the cat's visual cortex , 1991, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[33]  W Singer,et al.  Visual feature integration and the temporal correlation hypothesis. , 1995, Annual review of neuroscience.

[34]  Z Li,et al.  Contextual influences in V1 as a basis for pop out and asymmetry in visual search. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[35]  G Tononi,et al.  Modeling perceptual grouping and figure-ground segregation by means of active reentrant connections. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[36]  M. Mignard,et al.  Paths of information flow through visual cortex. , 1991, Science.

[37]  Geoffrey E. Hinton,et al.  Separating Figure from Ground with a Parallel Network , 1986, Perception.

[38]  T. Wiesel,et al.  The influence of contextual stimuli on the orientation selectivity of cells in primary visual cortex of the cat , 1990, Vision Research.

[39]  T. Wiesel,et al.  Targets of horizontal connections in macaque primary visual cortex , 1991, The Journal of comparative neurology.

[40]  Michael J. Hawken,et al.  Macaque VI neurons can signal ‘illusory’ contours , 1993, Nature.

[41]  T. Wiesel,et al.  Relationships between horizontal interactions and functional architecture in cat striate cortex as revealed by cross-correlation analysis , 1986, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[42]  B. C. Motter Focal attention produces spatially selective processing in visual cortical areas V1, V2, and V4 in the presence of competing stimuli. , 1993, Journal of neurophysiology.

[43]  W. Singer,et al.  Stimulus-specific neuronal oscillations in orientation columns of cat visual cortex. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[44]  T. Sacktor The Synaptic Organization of the Brain (3rd Ed.) , 1991 .

[45]  Steven W. Zucker,et al.  On the Foundations of Relaxation Labeling Processes , 1983, IEEE Transactions on Pattern Analysis and Machine Intelligence.

[46]  D. Hubel,et al.  Anatomy and physiology of a color system in the primate visual cortex , 1984, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[47]  C. Gilbert Horizontal integration and cortical dynamics , 1992, Neuron.

[48]  S. Nelson,et al.  An emergent model of orientation selectivity in cat visual cortical simple cells , 1995, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[49]  Christoph von der Malsburg,et al.  The Correlation Theory of Brain Function , 1994 .

[50]  David J. Field,et al.  Contour integration by the human visual system: Evidence for a local “association field” , 1993, Vision Research.

[51]  T. Wiesel,et al.  Clustered intrinsic connections in cat visual cortex , 1983, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[52]  D. Ts'o,et al.  Functional organization of primate visual cortex revealed by high resolution optical imaging. , 1990, Science.

[53]  David C. Somers,et al.  Vector-based Integration of Local and Long-range Information in Visual Cortex , 1995 .

[54]  Lance R. Williams,et al.  Local Parallel Computation of Stochastic Completion Fields , 1996, Neural Computation.

[55]  Victor A. F. Lamme The neurophysiology of figure-ground segregation in primary visual cortex , 1995, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[56]  Gert Cauwenberghs,et al.  Analog VLSI Cellular Implementation of the Boundary Contour System , 1998, NIPS.

[57]  Azriel Rosenfeld,et al.  Image Analysis and Computer Vision: 1998 , 1999, Comput. Vis. Image Underst..

[58]  Steven W. Zucker,et al.  Two Stages of Curve Detection Suggest Two Styles of Visual Computation , 1989, Neural Computation.

[59]  D. Fitzpatrick,et al.  Patterns of excitation and inhibition evoked by horizontal connections in visual cortex share a common relationship to orientation columns , 1995, Neuron.

[60]  David Marr,et al.  Vision: A computational investigation into the human representation , 1983 .

[61]  S. Grossberg,et al.  Contrast-sensitive perceptual grouping and object-based attention in the laminar circuits of primary visual cortex , 2000, Vision Research.

[62]  Christof Koch,et al.  Perceptual contour completion A model based on local, anisotropic, fast-adapting interactions between oriented filters , 1994 .

[63]  D. Field,et al.  Integration of contours: new insights , 1999, Trends in Cognitive Sciences.

[64]  N. S. Barnett,et al.  Private communication , 1969 .

[65]  R. Desimone,et al.  Selective attention gates visual processing in the extrastriate cortex. , 1985, Science.

[66]  H. Jones,et al.  Visual cortical mechanisms detecting focal orientation discontinuities , 1995, Nature.