The neural mechanisms for the visual recognition of objects extend beyond striate cortex into the surrounding prestiate and inferior temporal areas. Neurons in the prestriate areas appear to process local properties of objects such as the location of boundaries, while inferior temporal neurons appear to process more global features such as object shape. We are studying single neurons in prestriate and inferior temporal cortex to investigate both mechanisms. In prestriate cortex we have found that one area, area MT, is specialized for analyzing stimulus motion and contains direction-of-motion columns similar to the orientation columns discovered in primary visual cortex. In another area, area V4, we have found that neurons are sensitive to the length, width, and color of object contours and may play a role in separating figure from ground. In inferior temporal cortex we found that over half the neurons were tuned to a set of shape descriptors that can be used to code object shape. Since different neurons are tuned to different descriptors, a population of inferior temporal neurons could code any shape.
NIH ExPorter
NIH ExPorter