ACTIVATION ON THE MEDIAL WALL DURING REMEMBERED SEQUENCES OF REACHINGMOVEMENTS IN MONKEYS

We used the 2-deoxyglucose (2DG) method to map activation in the motor areas on the medial wall of the hemisphere. One group of monkeys lick ed juice delivered at variable time intervals (LICK task). For these a nimals, the motor areas on the medial wall displayed restricted activa tion. 2DG uptake was limited largely to the face representation of the supplementary motor area (SMA). Additional labeling was present more rostrally in the banks of the cingulate sulcus. A second group of anim als performed remembered sequences of reaching movements (REM task) fo r juice rewards. Activation related to licking also was present in thi s group. In addition, separate, discrete activations were found on the superior frontal gyrus and in the cingulate sulcus during the REM tas k. The most intense and extensive 2DG labeling was located in the dors al bank of the cingulate sulcus, coincident with the dorsal cingulate motor area (CMAd). Weaker activations were present in the arm area of the SMA and in the pre-SMA. There was no significant 2DG incorporation in the ventral bank of the cingulate sulcus where the ventral cingula te motor area is located. Our findings suggest that the CMAd is involv ed more than any other medial area in the preparation for and/or execu tion of highly practiced, remembered sequences of movements. Overall, our results indicate that the attributes of motor control are not repr esented equally across the motor areas on the medial wall.