[Spatial synchronization of brain potentials during extinctive inhibition]

The changes in spatial synchroneity of potentials in the cortex (SSCP) and several subcortical structures (some nuclei of the hypothalamus and non-specific nuclei of the thalamus) were studied in 11 rabbits in the course of extinction of defensive conditioned reflex (CR) to light. In the course of extinction, at the movement of the non-reinforced stimulation, specific increase in SSCP gradually disappears and the synchroneity between the cortex and subcortical structures decreases. In intersignal periods, at the stage of complete extinction, SSCP returns to the values prior to CR elaboration. The obtained data suggest that during CR extinction, a discrepancy of functional states gradually develops both between different cortical areas and between the cortex and the studied subcortical structures.