Low-frequency oscillations in human tibial somatosensory evoked potentials

• Main Author: Tierra-Criollo,Carlos Julio
• Publication Date: 2006
• Other Authors: Infantosi,Antonio Fernando Catelli
• Format: Article
• Language: eng
• Source: Arquivos de neuro-psiquiatria (Online)
• Download full: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0004-282X2006000300010
• topic: gamma oscillations; somatosensory evoked potential; tibial nerve; time-frequency analysis

Oscillatory cerebral electric activity has been related to sensorial and perceptual-cognitive functions. The aim of this work is to investigate low frequency oscillations (<300 Hz), particularly within the gamma band (30-110 Hz), during tibial stimulation. Twenty-one volunteers were subjected to 5 Hz stimulation by current pulses of 0.2 ms duration and the minimum intensity to provoke involuntary twitch. EEG signals without (spontaneously) and during stimulation were recorded at primary somatosensory area. A time-frequency analysis indicated the effect of the stimulus artifact in the somatosensory evoked potential (SEP) frequencies up to 5 ms after the stimulus. The oscillations up to 100 Hz presented the highest relative power contribution (approximately 99%) for the SEP and showed difference (p<0.01) from the frequencies of the spontaneously EEG average. Moreover, the range 30-58 Hz was identified as the band with the highest contribution for the tibial SEP morphology (p<0.0001).