EVOKED RESPONSES RECORDED FROM THE DEPTHS OF THE HUMAN BRAIN

The work that is about to be described has been made possible by the opportunity offered by clinical cases in whom electrodes have been implanted for diagnostic and therapeutic purposes. These same electrodes have been used for investigating in man the electrophysiological connections between the recording and stimulation points used for diagnostic purposes; they have also been used as recording points for detecting responses in deep structures to visual and auditory stimuli. This research is therefore only one facet of a larger program of clinical investigationf in which members of the Neurosurgical and Neurological Divisions, and the Departments of Anatomy and Psychiatry at the University of California Los Angeles are playing a part (R. Rand, P. Crandall, C. Markham, R. Walter, W. R. Adey and L. Chapman). All have collaborated in the work to be described. It is recognized that the purely neurophysiological investigations, reported here, are severely limited by three conditions : ( 1 ) The subjects do not have normal brains since they are cases of severe temporal lobe epilepsy, resistant to control by medication. ( 2 ) Only those electrode placements necessitated by the diagnostic goals have been used. ( 3 ) At all times the welfare of the patient has had to come first, and no test could be unduly prolonged. In no cases were electrodes implanted solely for experimental purposes.