Evoked Responses and Changes During Attentive Factors in Man

Abstract

Dawson,⁶in 1947, was the first investigator to describe the recording of evoked potentials over the scalp in man. A summation technique was employed permitting extraction of small signals from a noisy background with stimulation of the ulnar nerve. Derbyshire and associates,⁷Marshall and co-workers,²³and Adrian¹have described the variety of evoked potentials recorded from the cortical surface of animals during tactual or sensory neural stimulation. The study of potentials evoked at cortical sites in response to stimulation of deep brain regions has contributed to the understanding of cortical-subcortical relations.^2,14,24In detailed investigations with animals under barbiturate anesthesia, responses are divided into "primary," "secondary," and "repetitive" responses. Primary and secondary components of the evoked responses in man recorded from the scalp have been described by Cigánek.^4,5Jasper and associates¹⁹trported a technique for rapid recording and localization of evoked potentials from the