Limbic neuronal firing rates in man during administration of nitrous oxide oxygen or sodium thiopental

Abstract

Electroencephalographic activity and extracellular discharges from neurons in deep temporal lobe structures were recorded from fine wire microelectrodes chronically implanted in seven psychomotor epileptic patients for diagnostic localization of seizure foci. In four patients, inhalation of 80 per cent nitrous oxide resulted in loss of consciousness without change in firing rates of temporal lobe neurons (n=22). In all seven patients, thiopental (400 or 200 mg, iv) decreased limbic neuronal firing rates (n=38) until the return of wakefulness. In only three of these patients, however, did the firing rates of the neurons (n=19) decrease significantly (P