The effects of high-frequency microstimulation of the cortex on interhemisphere synchronization in the rat motor cortex.

Studies were carried out on long-term changes in the synchronization of neuronal activity in networks including callosal cells of the opposite hemispheres evoked by high-frequency microstimulation in the motor cortex of anesthetized rats. The level of synchronization was assessed in terms of the amplitude and width of peaks located symmetrically on cross-correlograms relative to the coordinate origin. Tetanization predominantly decreased synchronization in a group of initially background-active neurons, while there was a significant number of synchronously firing neurons in a group of cells which became activated. "Super-narrow" peaks appeared in interhemisphere interactions. There was a correlation between the type of modification of "narrow" (<20 msec) and "intermediate" (30-80 msec) peaks and changes in the efficiencies of mono- and polysynaptic connections.