The neurophysiology of figure^ground segregation in primary visual cortex

Recorded neuronal activity in the monkey primary visual cortex while Ss were viewing full screen arrays of either oriented line segments or moving random dots. Almost every cell gave a significantly larger response for texture elements perceived as a figure (FI) than for background elements. Cell responses were analyzed with the receptive field at various positions relative to the border of FI and ground (GD). Response enhancement was only present for positions where the receptive field was within the boundaries of the FI and was absent for positions outside of the FI, even when close to the boundary between FI and GD. This asymmetry shows that the lateral interactions observed are not simply due to lateral inhibition or other mechanisms related to the detection of edges. It appears that context modulation within a cortical area puts the cell-responsive features into their perceptual context of FI and GD.