Introduction
TO THE CRITICAL observer, an epileptic seizure has a pattern of activity which, although dramatic, is nevertheless as well coordinated and as integrated as many volitional activities of the neuromuscular system. If one observes repeated attacks in the same individual, it becomes obvious that the external manifestations of successive seizures are almost identical. Moreover, the individual who is subject to focal seizures recognizes that his attacks have a definite and predictable somatotopic and temporal sequence.Until recently, descriptions of the spread of convulsive activity have centered upon the cerebral cortex and only brief mention has been made of the participation of subcortical centers. Yet, early investigators, finding that a convulsive seizure initiated by electrical stimulation of the cerebral cortex would continue after that area had been acutely excised, concluded that the attack had spread to subcortical centers. Thus, Erickson,1 in 1940, stated that if the cortex