ROLE OF CORPUS-CALLOSUM IN INTER-HEMISPHERIC TRANSMISSION OF EPILEPTIC ELECTRICAL-ACTIVITY

  • 1 January 1978
    • journal article
    • research article
    • Vol. 27  (1) , 23-29
Abstract
In acute experiments on 49 curarized adult rats without general anesthesia, the transmission of discharges of cortical penicillin foci between the 2 hemispheres after transecting the corpus callosum was studied. Projected discharges of the cortical penicillin focus appeared in the contralateral hemisphere later than in the controls and had a very different shape. The interhemispheric response of the experimental rats consisted of a small positive and a small negative deflection with long latent periods. Focal discharges could be triggered by electrical stimulation of the contralateral hemisphere only irregularly and for short periods of time. In rats with a transected corpus callosum, 2 symmetrical cortical foci at 1st behaved independently of each other; their synchronization then slowly improved, but never attained 100%. The corpus callosum is the preferential pathway for interhemispheric transmission of focal activity. Transection of this pathway makes the transmission conditions much worse, but further connections, with a longer conduction time and lower efficacy, gradually come into action.