title: Low-frequency oscillations in human tibial somatosensory evoked potentials.
abstract: 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).
authors.affiliation: Biomedical Engineering Group, Electrical Department, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-010 Belo Horizonte MG, Brazil. carjulio@cpdee.ufmg.br
authors.forename: Carlos Julio
authors.initials: CJ
authors.lastname: Tierra-Criollo
authors.forename: Antonio Fernando Catelli
authors.initials: AF
authors.lastname: Infantosi
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006801:Humans; D008297:Male; D011930:Reaction Time; D013979:Tibial Nerve / Q000502:physiology*