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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: The results suggest that the projection to the superior colliculus in tree shrew and squirrel resembles that to striate cortex in that the region of the visual field corresponding to the intersection of the line of decussation and the horizontal meridian of the retina is represented in a larger area of the superiorColliculus than other portions of thevisual field.
95 citations
TL;DR: It is proposed that V3 contributes to the processing of stereoscopic depth information and that the parietal areas to which it projects use this information for the analysis of object depth and three-dimensional form.
Abstract: Recordings were made from single and small groups of cells in prestriate area V3 of the visual cortex of the Cynomolgus macaque (Macaca fascicularis). The majority of cells in V3 were selective for orientation and stereoscopic depth, these cells being segregated into two sets of functionally distinct columns. Orientation columns in V3 have been previously demonstrated; here we show that V3 also contains columns of segregated disparity-selective cells. On the basis of its cellular properties, functional organization, and intra-cortical connections, we propose that V3 contributes to the processing of stereoscopic depth information and that the parietal areas to which it projects use this information for the analysis of object depth and three-dimensional form.
95 citations
94 citations
TL;DR: The data suggest that the strongest input to cortical cells will arise from geniculate cells representing areas of visual space located at the borders of a visual stimulus, and suggests that analysis of response properties by patterns centred over the receptive fields of cells may give a misleading impression of the process of the representation.
Abstract: We have compared the spatial summation characteristics of cells in the primary visual cortex with those of cells in the dorsal lateral geniculate nucleus (LGN) that provide the input to the cortex. We explored the influence of varying the diameter of a patch of grating centred over the receptive field and quantitatively determined the optimal summation diameter and the degree of surround suppression for cells at both levels of the visual system using the same stimulus parameters. The mean optimal summation size for LGN cells (0.90°) was much smaller than that of cortical cells (3.58°). Virtually all LGN cells exhibited strong surround suppression with a mean value of 74%±1.61% SEM for the population as a whole. This potent surround suppression in the cells providing the input to the cortex suggests that cortical cells must integrate their much larger summation fields from the low firing rates associated with the suppression plateau of the LGN cell responses. Our data suggest that the strongest input to cortical cells will arise from geniculate cells representing areas of visual space located at the borders of a visual stimulus. We suggest that analysis of response properties by patterns centred over the receptive fields of cells may give a misleading impression of the process of the representation. Analysis of pattern terminations or salient borders over the receptive field may provide much more insight into the processing algorithms involved in stimulus representation.
94 citations
TL;DR: The results indicate that somatosensory cortex, like visual cortex, plays a critical role in modulating the responses of SC cells and suggests that the responsiveness of specific receptive-field regions may depend on the functional integrity of cortex.
Abstract: The corticotectal influences of somatosensory cortex were investigated by using reversible deactivation of cortex by cooling. More than half of the somatosensory superior colliculus (SC) cells stud...
94 citations