| Abstract: | A method is described for electrical stimulation of human subcortical brain structures. The necessity is shown for monitoring both the voltage across and also the current through the stimulated brain tissue, as well as the duration of the stimuli applied. Stimulus trains of constant composition were repeatedly applied to a ventrolateral-subventrolateral thalamic target area in 12 alert patients undergoing stereotaxic thalamotomy. Stimulation at the clinical threshold resulted in motor and “sensory” responses projected to contralateral parts of the body. In spite of small temporary variations, no distinct change of response from one stimulus train to the next in the same patient could be detected when the stimulation was applied at intervals of either 15, 30, or 60 sec. The current thresholds, on the other hand, showed a tendency to decrease if the intervals were less than 60 sec. The stimulation method and the results of stimulation are discussed. |
