Japanese Orthoptic Journal Vol. 21: 161-167(1993)

How is Visual Shape Processed by the Inferotemporal Cortex?




 The visual cortical areas of the monkey can be devided into two major streams, one involved in object vision and the other critical for spatial vision. The anterior part of the inferotemporal cortex(area TE)is situated at the final stage of the object vision pathway. Monkeys with lesioned TE cannot distinguish different shapes or recognize previously viewed objects. Except for cells selective for faces, TE cells respond to partial features of objects, and they are not selective enough to specify particular objects. Neurons responsive to similar object features cluster together within TE.. This clustering is vertically elongated in the direction of the cortical depth and patchy across the surface, thus forming columner structure. Linear width of each column is 0.4mm, and TE on one hemisphere is estimated to contain 2000 columns. Neurons within a column, although similar to each other in their stimulus preferences, show some differences in sensitivity to fine parameters of stimuli. This organization is suitable for encoding a vast variety of objects in a stable manner regardless of changes in illumination or viewing angles.