[Development of action potentials spreading antidromally from an acute epileptogenic focus through the corpus...

The activity of callosal neurones located in the sensorimotor cortical area was studied in unanaesthetized rabbits. An epileptogenic focus was produced by application of penicillin or strychnine in the homotopic region of the contralateral hemisphere. During hyperpolarization of the membrane, corresponding to the appearance of paraxysmal discharges in the homotopic area, some of the neurones exhibited a group of antidromic action potentials (APs) in their soma with a 70-80 msec latency. Analysis of the APs form and of interspike intervals between the tested APs and antidromic APs evoked by stimulation, allowed to identify spontaneous antidromic APs in the extracellular records of callosal neurones as well. The data obtained show that under the influence of epileptogenic agents in the axon terminals located in the focus of the epileptic activity APs may appear, spreading antidromally through the corpus callosum to the soma of the callosal neurones.