Periodic Microstimulation of Single Mechanoreceptive Afferents Produces Frequency-Following Responses in Human EEG. Kelly, Edward F., Mats Trulsson, Stephen E. Folger. Department of Diagnostic Sciences and Dental Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, Department of Physiology, Umeć University, S-901 87 Umeć, Sweden, Department of Biomedical Engineering and Dental Research Center, The University of North Carolina, Chapel Hill, North Carolina 27599.
APStracts 3:0233N, 1996.
Dense multichannel recordings of scalp EEG were obtained in the vicinity of primary somatosensory cortex, time-locked to repetitive train microstimulation of single, physiologically characterized skin mechanoreceptive afferents in the median nerve of a single human subject. Frequency-domain analysis of cross-trial averages for fast-adapting type one and slowly-adapting type one afferents revealed prominent, topographically organized "driving" responses in the EEG at the frequency of stimulation, which vanished under various statistical and experimental control conditions. The responses also exhibited systematic declines in amplitude both across and within trials, and orderly changes in scalp topography as a function of the location of afferents' receptive fields on the hand. The observed response properties are tentatively explained in terms of characteristics of the pattern of afferent drive impressed upon the cortex by microstimulation.

Received 17 April 1996; accepted in final form 27 September 1996.
APS Manuscript Number J321-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996