Three-dimensional shape coding in inferior temporal cortex

Neurons in the rostral lower bank of the superior temporal sulcus (TEs), pa rt of the inferior temporal cortex, respond selectively to three-dimensiona l (3D) shapes. We have investigated how these neurons represent disparity-d efined 3D structure. Most neurons were selective for either first-order (di sparity gradients) or second-order (disparity curvature) disparities. The l atter selectivity proved remarkably vulnerable to disparity discontinuities , such as sharp edges or steps in disparity. The majority of the neurons re mained selective for small disparity variations within the stimulus. 3D sha pe selectivity was preserved when the fronto-parallel position or the stimu lus size was altered. Thus, in TEs, 3D shape is coded by first- and second- order disparity-selective neurons, which are highly sensitive to spatial va riations of disparity.