[Effect of tranquilizers on cerebral cortex excitability in cats].

Chronic tests on cats showed that diazepam and nitrazepam lower the amplitude of primary responses (PR) of the second somatosensory zone of the brain cortex both to a single and paired stimulation of the thalamo-cortical radiation of fibers. Meprotan, while potentiating the PR to a single stimulation, does not influence the course of the PR restitution cycles. Benacryzine, while enhancing the PR to a single stimulation, produces the appearance of a lengthy phase of depression throughout the PR restitution cycle. In acute tests with unanesthetized, flaxedil immobilized cats, with an isolated cortical band underneath a stimulating electrode, analogous changes in PR both to a single and paired stimulation of the thalamo-cortical radiation of fibers were noted.