Abstract Carbachol and nicotine injected into the cerebral ventricles produced high amplitude and fast frequency activity in the electromyogram of conscious cats. Carbachol, much more than nicotine, caused bursts of such activity spaced at irregular time intervals accompanied by marked activity in the electrooculogram. In addition carbachol, but not nicotine, caused adynamia. The effect of nicotine lasted 3–5 hr, while the effect of carbachol lasted up to 6 hr. The obtained results suggest that central muscarinic and nicotinic mediations are involved in the activation of the motor efferent system.