Surround modulation in visual cortex can predict border-ownership selectivity: psychophysical study of...

Recent physiological studies revealed that neurons in the macaque visual cortex encode the direction of a figure along a contour (border ownership, BO). Although their cortical mechanisms have not been clarified, a computational model for BO has suggested that surround modulation in early vision can play an important role. Here we examined psychophysically how the strength of BO-dependent tilt aftereffect (BO-TAE) is modulated by a stimulus outside the adapted location in relation to the strength of surround modulation reported in physiological experiments. The results showed systematic change of the strength of BO-TAE, depending on the difference in orientation and spatial frequency between the bars placed outside and at the adapted location, indicating a crucial role of surround modulation in the neural mechanism underlying BO selectivity.