Putamen neuron spike activity associated with motor and nonmotor functions was studied in monkeys trained to behavioral programs consisting of a series of sequential actions. In general, each putamen neuron was activated during particular behavior fragments. The association of each individual neostriatal neuron with particular behavioral fragments was not constant. When the animal performed a different version of the same program (using different conditioned signals, right- or left-sided tasks, correct or erroneous performance), the neuron could lose its association with the animal's action and become involved in a different action to which it had previously produced no response. Thus, putamen neurons could demonstrate different functional modalities in different versions of the same actions. The use of additional versions of the given program always led to increases in the numbers of behavior fragments during which there were changes in the spike activity of the neurons of interest. This effect was significantly stronger in motor fragments of the program than in nonmotor fragments. These results show that putamen neurons do not have any defined specialization and have different functional modalities when the animal performs different versions of the same action. The nature of putamen neuron involvement in sensory-cognitive processes was more stable than in the organization of motor responses.

No abstract

Spike activity was recorded from several neurons in the monkey striatum during the performance of a complex behavioral program including differentiation of conditioned signals of different levels of complexity. The most characteristic feature of spike activity in striatal neurons during behavior was found not to be the selective involvement of particular neurons in carrying out certain actions, but a reflection of behavior as a whole in the form of mosaics of neuron activity corresponding to the moments at which particular actions were performed and during the intervals between them.

Experiments with simultaneous recording of six neostriatum neurons showed that the neurons of this structure are involved in the organization of all stages of behavior. A defined combination of neuronal activity corresponded to each action of the animal. The responses of individual neostriatal neurons were not entirely determined by the action being carried out at a particular moment, but reflected a wider aspect of the overall activity of the animal. These data, along with the established properties of neuronal responses in the neural network model, indicate that the integration of afferent signals in the neostriatum and their distribution to efferent connections is based on network mechanisms of neuronal interactions.

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.