During focal motor seizures induced by injecting penicillin into the face-hand area of the right motor cortex of 24-month-old monkeys, the sensorimotor system was manipulated by three methods. Elimination, by a paralytic agent, of proprioceptive input from contracting muscles and joints did not alter the electrographic expression of the seizure or the pattern of local glucose utilization in cortical or subcortical components of the sensorimotor system. An overall increase in the rate of energy metabolism occurred in the paralyzed monkeys with electrographic seizures. Cryogenic destruction of up to 90% of the ipsilateral ventral caudal globus pallidus had no effect on electrographic or clinical expression of the seizure. Electrical stimulation of the ipsilateral ventral caudal globus pallidus caused reproducible maximum expression of electrographic and clinical seizure phenomena for the 90-second duration of the stimulus.