title: Sustained changes in somatosensory gamma responses after brief vibrotactile stimulation.
abstract: Short-time passive tactile stimulation at 20 Hz improves tactile discrimination acuity. We investigated whether sustained 20 Hz stimulation also modifies cortical responses and whether these changes are plastic as indicated by differences between subsequent recording sessions. Touch stimuli (20 Hz) were applied to the fingertip, and β and γ oscillations at multiples of the stimulus frequency were recorded with magnetoencephalography. Neuromagnetic sources were found in the contralateral somatosensory cortex. β Responses decreased within a session, but recovered after a break between two sessions. In contrast, γ responses were consistent across repeated blocks and increased between the sessions. The differences between β and γ activities suggest that stimulus experience enhanced the temporal precision of the cortical stimulus representation, whereas the magnitude of the primary somatosensory response remained constant.
authors.affiliation: aRotman Research Institute, Baycrest Centre Departments of bMusic cMedical Biophysics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Shahab
authors.initials: S
authors.lastname: Jamali
authors.forename: Bernhard
authors.initials: B
authors.lastname: Ross
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D001931:Brain Mapping; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D015225:Magnetoencephalography; D008297:Male; D015999:Multivariate Analysis; D010812:Physical Stimulation; D013003:Somatosensory Cortex / Q000502:physiology*; D013997:Time Factors; D014110:Touch; D055815:Young Adult