Chemical plasticity of visual cortical neurons in integrative organization of feeding behavior in cats.

The P.K. Anokhin conception of organization of systemic behavior was used to study the discharge activity and chemical plasticity of cortical neurons in a goal-directed behavior. Chemical sensitivity of neurons in the visual cortex of instrumentally conditioned cats was studied during successive stages of food procuring and consuming. The results showed that definite stages of this integrated behavioral act are characterized by differences in the chemical sensitivity of visual neurons to neurotransmitters. The largest number of neurons resistant to neurotransmitters was found among cells that did not respond at successive stages of goal-directed behavior. The iontophoretic delivery of cycloheximide and lyzilvasopressine altered the discharge activity of individual cortical neurons at different stages of stereotyped instrumental conditioned acts. This suggests that the integrative organization of the feeding behavior is determined by chemical plasticity of the brain's visual cortical neurons and is dependent upon the processes of protein synthesis. According to the functional system theory (Anokhin, 1974) each brain neuron is included, by various degrees of freedom, in the stages of systemic organization that underlie the goal-directed behavior. Thanks to the plastic reorganization of brain units, each stage is directed toward the achievement of useful adaptive results for the organism during interaction with different environmental factors (Adrianov, 1993; Fadeev, 1988). It may be proposed that the reorganization of discharges of brain neurons that occurs at different stages of activity is due to changes in their chemical capacities. In concordance with such a hypothesis, the purpose of the present investigation was to study the chemical sensitivity of single visual cortical neurons to neurotransmitters at different stages of systemic organization of feeding behavior. The influence of protein synthesis inhibitors on the sensitivity of cortical neurons was also investigated.