Do N37 and P37 Potentials Have Different Generators in Somatosensory Evoked Potential? - Analysis Using Gating Mechanism -

Park, Young Seok; Cha, Jae Kwan; Kim, Sang Ho; Kim, Jae woo

Ann Clin Neurophysiol > 1999 ;1(2) > Article

Ann Clin Neurophysiol. 1999; 1(2): 106-111.

Young Seok Park, Jae Kwan Cha, Sang Ho Kim, and Jae woo Kim

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

Background : The generators of N37 and P37 of posterior tibial nerve somatosensory evoked potential(PTSEP) have not been exactly known. Recently, some reports suggested that P37 and N37 might have different generator. We conducted a study to know the generators of P37 and N37 of PTSEP using gating mechanism. Methods : We evaluated subcortical and cortical somatosensory evoked potentials(SEPs) in response to posterior tibial nerve stimulation in 2 experimental conditions of foot movement and compared them with PTSEPs in full relaxation of foot. The experimental conditions were: (a) active flextion-extention of stimulated foot, (b) isometric contraction of the stimulated foot, (c) passive flextion-extention of the stimulate foot. We analyzed the latencies and amplitudes of following potentials;P30, N37, P37, and N50. Results : The amplitude of P30 potential did not change during at any paradigms. Te amplitudes of P37 and N50 were significantly attenuated in all condition. However, the amplitude of N37 showed no significant change during at any paradigms. Conclusions : These results suggest that the generators of P37 and N37 pf PTSEP be different I cortex.

Key words: Somatosensory evoked potential, Generator, Gating