Cortical and subcortical electrical activity in experimental seizures induced by metrazol.

The convulsant drug, metrazol, has long been known to produce experimelltal seizures of the grand ma1 type and, more recently, has been employed clinically, either in shock therapy for patients with mental disease (11) or as an aid in the diagnosis of suspected epilepsy (2, 3, 8, 12, 16). Administration of ~ubconvuls i~~ doses of metrazol has been used to provoke abnormal discharge in the electroencephalogram of epileptic patients durilx inter-seizure periods (2, '12, 16). In addition, similar doses of metrazol have been utilized in conjunction with photic stimulation (3) or direct stimulation of the brain (8) in the case of focal epilepsy, to induce controlled seizures. This usefulness of metrazol in the study of seizures in man makes it desirable to learn more of its action upon the brain (1, 4, 5, 9). The present experiments have investigated the alterations in cerebral electrical activity during metrazol seizures in the cat. Because of growing interest in subcortical influences upon the activity of the cerebral cortex, special attention has been directed to the participation of deep brain structures and, in particular, that of thalamic nuclei in the metrazol fit.