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Qasim Zaidi, Erin Koch, Jianzhing Jin, Jose-Manuel Alonso; Genesis of pattern and contour selectivity by intra-cortical circuits: functional implications of the pinwheel mosaic. Journal of Vision 2017;17(7):29. doi: 10.1167/17.7.29.
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© ARVO (1962-2015); The Authors (2016-present)
We distinguish shapes by contours, and surfaces by patterns and textures of multiple orientations and scales, despite retinal response compression leading to cross-orientation suppression. In striate cortex of primates and carnivores, orientation preference is arranged as iso-orientation domains that radiate circularly from pinwheel centers. Using tangential penetrations with multi-electrode arrays, we found that orientation tuning is narrower, and contrast saturation and cross-orientation suppression stronger, within iso-orientation domains than at pinwheel centers. These differences develop due to excitation (not normalization) from neighboring oriented neurons. As a result of these local intra-cortical computations, narrower tuning, greater cross-orientation suppression and higher contrast gain of iso-orientation cells, lead to extraction of object contours from images; whereas broader tuning, greater linearity and less suppression of pinwheel cells, generate selectivity for surface patterns and textures.
Meeting abstract presented at the 2016 OSA Fall Vision Meeting
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