The Neural Control of Vision
N. Intermediate Level Vision

The role of area V4 in intermediate vision has been extensively studied in the Schiller lab using both single-cell recordings and lesions. Figure 73 shows how the ability to select objects in a match to sample task is affected by V4 lesions. The monkey is trained over an extended time period to make an eye movement to the target that matches the one that first appears in the center. On the left performance is shown on this task for several pre-operative days and then for 24 post-operative days. The monkey does extremely well before the V4 lesion. Right after it his performance at the site where the V4 representation had been ablated is very poor, but then gradually improves. When one then introduces a new figure, as shown on the right, the monkey does well with it at intact sites but does poorly at the lesion site but gradually improves. This effect can be repeated over and over suggesting that area V1 and the areas with which it interconnects, play an important role in visual learning.