The neural basis of image segmentation in the primate brain.

Image segmentation is a fundamental aspect of vision and a critical part of scene understanding. Our visual system rapidly and effortlessly segments scenes into component objects but the underlying neural basis is unknown. We studied single neurons in area V4 while monkeys discriminated partially occluded shapes. We found that many neurons tuned to boundary curvature maintained their shape selectivity over a large range of occlusion levels as compared to neurons that are not tuned to boundary curvature. This lends support to the hypothesis that segmentation in the face of occlusion may be solved by contour grouping.