Putamen: activity of single units during slow and rapid arm movements.

The activity of putamen neurons was studied in a monkey during the performance of both slow and rapid arm movements. More than half of all movement-related units discharged preferentially in relation to slow movements and less than 10 percent in relation to rapid movements. These findings indicate that at least a portion of the basal ganglia (the putamen) is primarily involved in the control of slow movements and are consistent with the hypothesis of Kornhuber that the primary motor function of the basal ganglia is to generate slow ("ramp") rather than rapid ("ballistic") movements.