[Dynamics of spatial synchronization of epileptiform discharges in the rat neocortex]

Epileptiform potentials after the application of GABA A receptor antagonist first appeared in a local part of the cortex of anesthetized rats, and then with a small time lag appeared in other areas of the cortex. Externally, it looked like spreading. Potentials originally appeared at any point of recording, and then appeared (propagated) both in the rostral-caudal direction (forward) and reciprocally. The quantitative evaluation of this phenomenon showed that there are three periods of the epileptiform potential spreading. During the initial period, the epileptiform potentials appeared and spread relatively equally in rostrocaudal direction and backwards. In period 2 dominated potentials shift in rostrocaudal direction. After application of a sodium channel blocker epileptic activity significantly decreased. Frequency of initial appearance of potentials in the caudal areas increased. Propagation of the activity in one or another direction was observed. Obtained in this study quantitative characteristics of the initiation and spreading of epileptic activity suggest that in the cortex may exist independent generators, and distribution of the epileptiform potentials and the nature of this distribution implies that this process is based on direct and reciprocal functional connection of neurons.