Neuronal manifestation of two-way connections in conditioning

Neuronal characteristics of two-way conditional connections were studied in chronic experiments with alert cats during different types of alimentary conditional reflexes. Single unit and multi-unit activities were chronically recorded in the visual and motor cortex and the lateral hypothalamic nucleus. Cross-correlational analysis of neuronal impulse trains was used to characterize the organization of neuron groups in brain structures involved in the formation of a conditional reflex. The experimental data showed an increase in the number of neuronal two-way connections after learning in all three investigated coordinations: visual-motor, visual-hypothalamic, and motor-hypothalamic. With visual-motor interneuronal coordination, the strengthening of two-way connections was due to the enhancement of connections from the motor to the visual neuron (backward connections); with visual- and motor-hypothalamic coordination, the number of interneuronal connections was equal in both directions. In all investigated coordinations, the analysis of the temporal parameters of the interactions between the neurons of different groups showed a dependence of the conditioning procedure on delays of up to 30 ms and a dependence of the motivational state on the interval range of 90-100 ms. The polyfunctional and polycomponent character of two-way neuronal connections in conditioning can be inferred from these data. Evaluation of the activity of neurons of different brain structures suggests the specific organization of intracortical and cortical-subcortical integrity in learning.