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Orientation column

About: Orientation column is a research topic. Over the lifetime, 1142 publications have been published within this topic receiving 130169 citations.


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TL;DR: On the basis of the organization of their receptive field, the authors have been able to differentiate four classes of cells in the cat's striate cortex: simple, complex, and two distinct classes of hypercomplex cells.
Abstract: .here has already been some discussion concerning hierarchical versus parallel processing of information in the striate cortex and I would like to add a few comments. Hubel and Wiesel,' in their classical papers, differentiated three categories of cells in the cat's striate cortex. They further suggested a hierarchical model which would explain the organization of the receptive fields of each type of cell. Thus only simple cells would receive a direct excitatory input from lateral geniculate neurons (LGN), and a number of simple cells with a common optimal orientation and slightly offset receptive-field positions would then provide the excitatory input to the complex cells. Finally, different complex cells with a common preferred orientation but again with offset receptive-field positions would provide excitatory and inhibitory inputs to the hypercomplex cells. The inhibitory input to the hypercomplex cell would explain that the sharp reduction in the discharge, as an optimally oriented stimulus, is elongated beyond the excitatory region in the receptive field. If the Hubel and Wiesel model is correct, one would expect a basic similarity between the responses of complex and hypercomplex cells. However, on the basis of the organization of their receptive field, we have been able to differentiate four classes of cells in the cat's striate cortex: simple, complex, and two distinct classes of hypercomplex cells. The majority of hypercomplex cells (Fig. 1, Type 1) have responses very similar to those of simple cells and their receptive fields can be subdivided into

141 citations

Journal ArticleDOI
TL;DR: It is reported that neurons in macaque area V4, an intermediate stage in the ventral (object-related) pathway of visual cortex, were tuned for 3D orientation—that is, for specific slants as well as for 2D orientation.
Abstract: Tuning for the orientation of elongated, linear image elements (edges, bars, gratings), first discovered by Hubel and Wiesel, is considered a key feature of visual processing in the brain. It has been studied extensively in two dimensions (2D) using frontoparallel stimuli, but in real life most lines, edges and contours are slanted with respect to the viewer. Here we report that neurons in macaque area V4, an intermediate stage in the ventral (object-related) pathway of visual cortex, were tuned for 3D orientation—that is, for specific slants as well as for 2D orientation. The tuning for 3D orientation was consistent across depth position (binocular disparity) and position within the 2D classical receptive field. The existence of 3D orientation signals in the ventral pathway suggests that the brain may use such information to interpret 3D shape.

139 citations

Journal ArticleDOI
TL;DR: The results suggest that horizontal connections play a significant role in shaping the visual responses of layer 2/3 neurons, without compromising spatial resolution along the collinear axis.
Abstract: The superficial layers of primary visual cortex, unlike layer 4, have an extensive network of long-range horizontal connections linking sites of similar orientation preference. To identify possible functional consequences of this distinct anatomy, we compared the receptive field properties of layers 2/3 and 4 neurons in tree shrew primary visual cortex with electrophysiological recordings. We found that elongated receptive fields, strong orientation tuning, and length summation (properties predicted by the anatomy of the horizontal connections) are present in layer 2/3 neurons, but not in layer 4 neurons. We further characterized the summation fields of layer 2/3 neurons and found axis and orientation-specific facilitation that matched the distribution of horizontal connections. The functional signature of horizontal connections was also evident in the population response of layer 2/3 neurons; the intrinsic signal activation pattern elicited by an array of collinear Gabor elements was significantly stronger than that elicited by a noncollinear array. Furthermore, our results showed that this enhancement of population response was achieved without compromising spatial resolution along the collinear axis, providing stimulus-specific facilitation without filling in between stimuli. Taken together, these results suggest that horizontal connections play a significant role in shaping the visual responses of layer 2/3 neurons.

139 citations

Journal ArticleDOI
05 Jun 1997-Nature
TL;DR: It is found that the map of visual space on cat V1 shows strong and systematic local distortions in register with inhomogeneities in the orientation map, with the rate of receptive field movement across cortex being largely proportional to the local rate of change of orientation.
Abstract: The map of orientation columns in primary visual cortex (V1) is known to show strong local distortions, with a generally smooth progression of orientation preference across extended regions of cortex, interrupted by sharp jumps (fractures) and point singularities. The map of visual space on V1, in contrast, has been assumed to be locally smooth and isotropic. We find, on the contrary, that the map of visual space on cat V1 shows strong and systematic local distortions in register with inhomogeneities in the orientation map, with the rate of receptive field movement across cortex being largely proportional to the local rate of change of orientation. This suggests possible systematic local variations in the functional connectivity of short-range lateral connections that underlie local cortical processing.

139 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231
20223
20212
20208
20192
20189