The properties and possible mechanisms of interhemisphere synchronization in the motor cortex of the rat

Cross-correlation analysis was used to observe interhemisphere synchronization of motor cortex neuron activity in anesthetized rats, which was seen on cross-correlograms as peaks located symmetrically relative to the coordinate origin. Peaks included "narrow" peaks (less than 20 msec) and "intermediate" peaks (30-80 msec). The results showed that the "common" source synchronizing the discharges of pairs of neurons located in different hemispheres of the brain might be a neuron (or group of neurons) located in one of the hemispheres and playing this role when there were reciprocal excitatory connections between it and each neuron in a pair. Comparison of the widths of symmetrical peaks with latent periods corresponding to transcallosal connections suggested that mono- and polysynaptic connections underlie the formation of "narrow" and "intermediate" peaks respectively.