EFFECT OF CURARE ON CORTICAL RESPONSES EVOKED BY AFFERENT STIMULATION

Abstract

Cortical responses were evoked in cats by stimulation of the brachial plexus and the spinal cord. Anesthesia was with nembutal or ether, and artificial respiration was provided. When the control response had been recorded, into-costrin or d-tubocurarine was injected intraven. in repeated small amts. By giving enough of the drug, it was always possible to depress, and finally to eliminate, both the secondary cortical discharge and the primary cortical response. When the spinal cord was stimulated, an immediate small spike was obtained as a result of retrograde transmission over the pyramidal tracts. This impulse was not affected by the curare. Spontaneous cortical electrical activity disappeared before synaptic conduction was blocked. The doses required for the depression of synaptic conduction were usually greater by a factor of 10 or 15 than the doses required for blocking neuromuscular conduction.