Intracellular potentials of cortical neurons during focal epileptogenic discharges.

Focal electroencephalographic discharges in lesions of cortex induced by freezing are associated with prolonged membrane depolarizations and hyperpolarizations in neurons located at various depths in the lesion sites. Transmembrane potential changes have properties similar to those of postsynaptic potentials. The temporal relationship between intracellular potentials and paroxysmal discharges indicates that the latter are extracellularly recorded summations of synchronously developing depolarizations and hyperpolarizations in complex synaptic organizations of neurons.