NEOCORTICAL IMPACT ON THE AUDIOGENIC SEIZURE ACTIVITY DEVELOPMENT.

ABSTRACT

Out of genetically determined epilepsy models a special interest draws the model of audiogenic seizures, which does not require whatever additional intervention (e.g. pharmacological or/and electric stimulation), because epileptic responses are elicited by specific sensory stimulation only. Notwithstanding the fact that different formations of the central nervous system are recruited in audiogenic seizure reactions, critical importance for the manifestation of this type epilepsy is attributed to the inferior colliculus and brainstem reticular nuclei. Significance of the diencephalic structures and the thalamic reticular nucleus, in particular for development and/or modulation of audiogenic seizures is ambiguous. Total of eight Krushinsky- Molodkina (KM) strain rats, weighting 250-300 g, served as the subjects of chronic experiments. The neocortex was bilaterally activated by way of administration of 1 µl strychnine (0.1% solutipon) with a microsyringe through a metal capillary prefixed on the cortical surface. Metal electrodes for recording electrical activity were implanted into the neocortex and brainstem reticular formation. Experiments have shown that against strychnine discharges in the neocortex there occurred an increase in the latency of wild runs and the pause between the first and second wild runs in response to a sound stimulus. Proceeding from the above-said, it can be assumed that activation of the neocortex must stipulate intensification of the thalamic reticular nucleus neuronal activity that, in turn, should have a modulating effect on the audiogenically induced seizure reactions.