SPONTANEOUS GAMMA-OSCILLATIONS IN NEURAL NETWORKS WITH TRANSCALLOSAL CONNECTIONS

The evidence obtained from the studies of EEG high-frequency component s and computer simulation which determined the necessary conditions fo r occurence of oscillations were compared with some features of sponta neous gamma-oscillations, which had been revealed by us in interconnec tions of neurons located in symmetrical loci of both hemispheres of mo tor cortex of anaesthetized rats. Based on the similarity of the most expressed high-frequency EEG components and dominant frequencies of ga mma-oscillations, we proposed that gamma-oscillations could underlie t he appearance of the high-frequency EEG components. Taking into accoun t the obtained by us results that interhemispheric oscillations occurr ed 1.5 times more frequently than ipsilateral and the evidence from co mputer simulation experiments that reciprocal inhibition underlies osc illations in neural networks, we suggested that transcallosal inhibiti on was more effective than inhibition between the neighbouring cells. Parameters of simultaneously revealed spontaneous oscillations caused by interhemispheric and ipsilateral Interactions land in individual ce ll activity could be different. It was assumed that functional variabi lity of local neocortical networks and participation of different inhi bitory neurons underlie distinctions in oscillation parameters.