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The dynamics of tonic neuron activity of the putamen and prefrontal cortex of monkey's brain is researched by studying sequential stages of executive behavior program. It is determined that tonic responses in both structures are classified in separate blocks. The blocks are timed to key moments of behavior connected with intermediate goals framed by a common task. As to the structures of the aforesaid blocks of tonic activity in cortex and striatum, they are different in instructive part of the program and similar in executive one. More differential attitude of cortex is revealed to the sequence of executive behavior activity.

In human striatum and basolateral amygdala NADPH-d+ neurons were revealed (after Vincent et al., 1983); and in striatum strio-cortical neurons were also revealed using DiI marker (after Dahtstrom and Belichenko, 1995). The NADPH-d+ neurons were numerous in both formations. Staining of NADPH-d+ neurons with their processes, and our previous study of striatal and amygdalar human neurons by Golgi method made it possible to identify the species of neurons with their assessment as sparsely or densely branched. The main efferent neurons of striatum and basolateral amygdala (densely branched medium spiny and bushy spiny, respectively) and their densely branched interneurons were not marked. Efferent NADPH-d+ neurons included the most numerous ones in both formations. A projection of reticular striatal neurons to cortex was also shown. The NADPH-d+ interneurons belonged to sparsely branched forms. In striatum they included slender-dendritic and long-dendritic bipolars (numerous), ordinary bipolars, twisted and large poor-dendritic cells; in amygdala--the same bipolars and radial cells. Thus, the NADPH-d positive cells in the formations under study were represented by more "ancient" or less structurally complex cell forms.

Simultaneous recording of unit activity of 6-8 putamen neurons in two monkeys (M. nemestrina and M. mulatta) during performance of the task of alternative spatial choice, was carried out. The extent of rearrangements of the activity in the groups of neurons with the transition from every step of the behavioral program to the next one and the degree of difference in mosaics of reactivity, forming at every step with a different variants of performance, were evaluated using discriminative analysis. The rearrangements of the impulse activity were recorded in all steps of the program. The dynamics of rearrangements with the choice of right or left feeder was different, which resulted in appearance of significant differences in mosaics of reactivity at the stage of decision making and receiving reward. The rearrangements preceding the task-oriented movement of one hand were more pronounced in the contralateral hemisphere. The volume of rearrangements may increase with the performance of movement but the differences of mosaics formed during the movement of right and left hand are decreasing. At the stage of reception of the reward, the rearrangements were greater in case the animal chose the certain (left) feeder irrespective of the side of recording the unit activity.

Single unit activity was recorded in monkeys in three putamen zones learned a bimanual operant activity during performance of the task of alternative spatial choice. The neuronal reactions were specially analyzed by the criteria as follows: a) differentiation of the side of reward (differentiating--non-differentiating reactions); b) character of reaction by duration (tonic-phasic); c) laterality (contra- and ipsilateral reactions as related to hemisphere); d) frequency of background activity. It was shown that differentiating cell activity, especially their tonic part and in still greater degree contra-lateral tonic reactions most closely correlate with behavioral aspects of the program. The assumption that differentiating activity, unlike non-differentiating one, is the reflection of not only morphological and neurochemical characteristic features of nervous elements of putamen but of its functional uniformity in relation to external determinants of behavior, was put forward.

Comparative analysis of the unit activity of the monkey putamen during multistage behavior showed that neurons of the putamen are active during all the behavioral actions. It was established that the number of the behavior-related neurons changes considerably less than number of neurons which reorganize their activity at the time. Reorganization of unit activity in the putamen is considered as reflecting the efferent code which controls behavior, and the degree of reorganization--as a measure of change of this code in relation to organization of ongoing behavioral action. It has been discovered that the change in the number of the active neurons at various steps of behavior and reorganization of their activity occurs independently. It may be related to two main afferent systems of striatum: ascending from rhe brain stem, and corticofugal which brings differentiated information to the neuronal net of striatum from various parts of the cortex.