Orientation column

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

Topological singularities in cortical orientation maps: the sign theorem correctly predicts orientation column patterns in primate striate cortex

Abstract: Optical imaging methods have revealed the spatial arrangement of orientation columns across striate cortex, usually summarized in terms of two measurements at each cortical location: (i) a ‘best’ stimulus orientation, corresponding to the stimulus orientation that elicits a maximal response, and (ii) the magnitude of the response to the best orientation. This mapping has been described as continuous except at a set of singular points (also termed ‘vortices’ or ‘pinwheels’. Although prior work has shown that vortex patterns qualitatively similar to those observed in visual area 17 of the Macaque cortex can be produced by either band-pass or low-pass filtering of random vector fields, there has been to date little further topological characterization of the structure of cortical vortex patterns. Nevertheless, much theoretical work has been done in other disciplines on mappings analogous to the cortical orientation map. In particular, a recent theorem in the optics literature, termed the sign principle, stat...

Differences in orientation and receptive field position between supra- and infragranular cells of cat striate cortex and their possible functional implications

Abstract: On the postlateral gyrus of the cat striate cortex the cells' preferred orientation and the location of their receptive fields was measured as a function of cortical depth in penetrations as parallel as possible to the radiating fibres. In most penetrations the majority of infragranular cells showed orientation preferences 45°---90° different from the preferred orientations of supragranular cells. In addition, aggregate receptive fields from the same eye of supra- and infragranular cells were spatially shifted against each other. Using different columnar models these results are discussed in terms of spatial contrast enhancement for two parallel mechanisms in upper and lower layers, determined for pattern discrimination and movement detection.

Retinal projection in the forebrain of Emys orbicularis.

Abstract: The latency and amplitude of evoked potentials in the general cortex of the turtle forebrain depend on localization of a point light source in the visual field. Maximal evoked responses show that retinal quadrants are connected predominantly with corresponding areas of the forebrain cortex. Most neurons (70 or 80) have wide receptive fields commensurate with the entire visual field. Distribution of the most effective points within the receptive field of the neurons also indicates their predominant connection with certain retinal quadrants. All dorsal cortical neurons exhibit high reactivity to displacement of objects in the visual field. A stationary light source also evokes different unit responses in the surface and deep layers of the cortex.