Response to motion in extrastriate area MSTl: center-surround interactions

Abstract

2462–2475, 1999. Many neurons in the lateral-ventral region of the medial superior temporal area (MSTl) have a clear center surround separation in their receptive fields. Either moving or stationary stimuli in the surround modulates the response to moving stimuli in the center, and this modulation could facilitate the perceptual segmenta-tion of a moving object from its background. Another mechanism that could facilitate such segmentation would be sensitivity to binocular disparity in the center and surround regions of the receptive fields of these neurons. We therefore investigated the sensitivity of these MSTl neurons to disparity ranging from three degrees crossed disparity (near) to three degrees uncrossed disparity (far) applied to both the center and the surround regions. Many neurons showed clear disparity sensitivity to stimulus motion in the center of the receptive field. About 1⁄3 of 104 neurons had a clear peak in their response, whereas another 1⁄3 had broader tuning. Monocular stimulation abolished th