Responses of striate cortical cells to moving edges of different curvatures.

The responses of twenty cells to stimuli of varying curvature were measured in cat's striate cortex. All the investigated cells were sensitive to the orientation of lines and not hypercomplex. Fourteen cells showed a systematic change of response with curvature. The optimal curvatures of the cells were distributed over the whole range investigated. Six cells were insensitive to curvature. The responses from all the typical simple cells (8) varied with curvature, whereas all the complex cells (5) were insensitive to curvature changes. The curvature tuning curves were broad and the variability to individual stimuli was high, independent on whether the cell responded best to straight or to curved edges. The findings do not support the view that individual cells of area 17 could detect curvature.