Correlates of sequential elements of bimanual behavior in the neuronal activity of the neostriatum in monkeys.

Abstract

Neuron spike activity was recorded in the putamen of monkeys trained to perform bimanual operant behavior consisting of nine separate steps. Neuronal reactions were present at all steps: in 52-62% of cases during movement, and in 27-36% of cases during responses to the trigger and conditioned signals and as the monkeys decided which was the working hand. The proportion of inhibitory responses to the trigger stimulus was 9%, while inhibitory reactions accounted for 68% of reactions during hand movement in response to the conditioned signal, 33% of reactions when this same hand was used to collect food reinforcement, and 33% of reactions during simultaneous movement of both hands. Reactions significantly differentiating between right- and left-sided tasks were seen at all stages of working-hand decision-taking and in reactions to the signal indicating the correctness of the selection, but were not seen for reactions to the conditioned signal or for activity accompanying movements of one of the animal's hands. These data provide evidence indicating that each step of the complex operant behavior, individual systems of putamen neuronal reactions were created with qualitatively different integral sensitivity to instantaneous behavior.