Collective responses of neostriatal (putamen) neurons during alternative behavior in monkeys.

A monkey (Macaca nemestrina) was trained to perform a behavioral program consisting of the selection and execution of a defined sequence of actions according to a visual conditioned signal. Discriminant analysis was used to evaluate the parameters of the collective activity of six simultaneously recorded putamen neurons. The collective activity of the neurons showed significant differences associated with execution by the monkey of left- and right-sided tasks. These differences were seen to be quite consistent in different groups of neurons. Despite the fact that putamen neurons were involved in the performance of nine separately analyzed fragments of the program, differences were seen in two of these: at the moment of taking the decision relating to the direction of movement, and after its completion when a signal indicating the completed result was presented, independently of whether the animal selected the side for the action correctly or incorrectly. In the case of erroneous decisions, the response mosaic differed from that obtained for correct decisions; however, differences due to previously taken decisions regarding the side of action were preserved. These differences were greater at the point of program completion than at the moment of deciding the direction of movement.