Effects of lesioning the anterior suprasylvian cortex on visuo-motor guidance performance in the cat.

Seven cats were trained to press a lever that moved in front of them at an adjustable speed and at random from left to right or from right to left. Efficient presses were reinforced by food. After measuring accuracy and latency of pressing the lever, the animals underwent bilateral ablation of the suprasylvian (SS) cortex; in three animals the lesions involved its anterior aspect; in two animals, they were restricted to its middle portion; two other cats had lesions of both anterior and the middle SS cortex. No long-lasting postoperative deficits were observed in any group when the lever remained immobile. On the other hand, the scores after anterior SS lesions were severely deteriorated, when presses had to be performed on the moving lever. No such deficits were noticed when the ablations were restricted to the middle SS. These results suggest that the cat anterior suprasylvian cortex (that includes parts of areas 5 and 7) plays a determinant role in the spatial adjustment of a visually guided (or visually triggered) forelimb movement.