Intraanalyzer conditioned reflex properties of two-way connections of cortical neurons in cats

One of the principles in the formation of integrating activity of the brain appears to be a two-way character of neuronal connections. Forward and backward conditioned connections demonstrate the acquired properties of two-way relations in the cerebral cortex. Interneuronal cortical connections and their modification in conditioned reflex activity were studied in a alert cats with chronically implanted electrodes using a statistical method for analysis of two impulse flows. Multineuronal activity was recorded in the auditory cortex. All of the investigated neurons were divided into pairs according to their functional relations: (1) with two-way connections, (2) with one-way connections and (3) completely independent pairs. The functional interrelation in the cortical microarea, and between cortical microareas, were defined according to the space distribution of neuronal pairs. Elaboration of the motor conditioned reflex led to an intensification of two-way connections both in the cortical microarea and between remote neurons. Extinction of the conditioned reflex exerted almost no effect on the intensity of two-way connections, but considerably decreased the number of independent neuronal pairs at the expense of reduction in the number of one-way connections between cortical microareas. Thus, acquisition and extinction of the conditioned reflex were accompanied by intensive interconnected neuronal activity. The features of interneuronal connection properties during extinction inhibition were the attenuation of successive information transfer in cortical cells, which prevented the impulse activity from passing to effector pathways.