Depth electrographic study of a fast rhythm evoked from the human calcarine region by steady illumination

摘要: Abstract In the course of investigation following implantation depth multielectrode leads in an epileptic patient a fast discharge was observed one electrode, located left occipital lobe, when lights room were switched on and off. On basis roentgenographic evidence as well results visual, photic electric stimulation, electrode involved this phenomenon estimated to be anterior calcarine cortex or underlying white matter. Constant illumination (18 1200 foot-candles) provoked part brain response characterized by initial slow potential (“slow on-response”), followed around 50 c/sec. This evolved after variable time into 20 25 that gradually declined usually over 30 35 sec. (“fast on-response”). A pattern similar on-response, but lower voltage shorter duration, stimulus off (“slow” “fast” off-response). The reduced closure eyes enhanced at their opening. present sometimes intensified during sleep. Various effects could changing duration intensity illumination. There some degree similarity between “on” “off” (1) lambda waves (2) responses intermittent stimulation low rate. These findings are discussed previous animal experiemental studies.