Neurophysiological mechanisms of cortical-subcortical interactions in the organization of behavior.

Experimental data are discussed within the framework of the fundamental areas of studies of the neurophysiological mechanisms of behavior. The first of these is the study of the activity of individual neurons, which is characterized by plastic rearrangements based on synaptic, molecular (neurochemical), and submolecular (genetic) processes. The second area is the study of the activity of neuron systems, which unite the cells of different microgroups, and of systems including neural elements of different brain structures. Data on plastic rearrangements of neuronal activity in different structures during different types of behavior lead to the conclusion that the brain has special systems of relationships which characterize the interactions of blocks of neurons, in which the plasticity of a single neuron can maintain the integration processes of the whole system. Our own data, along with results of Russian and foreign physiological and clinical investigations, suggest that neurons unite into different functional blocks at different phases of conditioned reflex behavior, thus determining the dominance status of different centers and the vector of a purposive behavioral act in a given situation at a given time. Possible directions for further basic studies of the interactions between innate and phylogenetically acquired functionally specific neuron units are discussed on the basis of hypotheses which have been advanced to explain the neurophysiological organizational mechanisms of higher brain functions.