title: Steady-state activation in somatosensory cortex after changes in stimulus rate during median nerve stimulation.
abstract: Passive electrical stimulation activates various human somatosensory cortical systems including the contralateral primary somatosensory area (SI), bilateral secondary somatosensory area (SII) and bilateral insula. The effect of stimulation frequency on blood oxygenation level-dependent (BOLD) activity remains unclear. We acquired 3-T functional magnetic resonance imaging (fMRI) in eight healthy volunteers during electrical median nerve stimulation at frequencies of 1, 3 and 10 Hz. During stimulation BOLD signal changes showed activation in the contralateral SI, bilateral SII and bilateral insula. Results of fMRI analysis showed that these areas were progressively active with the increase of rate of stimulation. As a major finding, the contralateral SI showed an increase of peak of BOLD activation from 1 to 3 Hz but reached a plateau during 10-Hz stimulation. Our finding is of interest for basic research and for clinical applications in subjects unable to perform cognitive tasks in the fMRI scanner.
authors.affiliation: Department of Neurological and Vision Sciences, Section of Neurological Rehabilitation, Gianbattista Rossi Hospital, University of Verona, 37134 Verona, Italy. paolo.manganotti@univr.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Manganotti
authors.forename: Emanuela
authors.initials: E
authors.lastname: Formaggio
authors.forename: Silvia Francesca
authors.initials: SF
authors.lastname: Storti
authors.forename: Mirko
authors.initials: M
authors.lastname: Avesani
authors.forename: Michele
authors.initials: M
authors.lastname: Acler
authors.forename: Francesco
authors.initials: F
authors.lastname: Sala
authors.forename: Stefano
authors.initials: S
authors.lastname: Magon
authors.forename: Giada
authors.initials: G
authors.lastname: Zoccatelli
authors.forename: Francesca
authors.initials: F
authors.lastname: Pizzini
authors.forename: Franco
authors.initials: F
authors.lastname: Alessandrini
authors.forename: Antonio
authors.initials: A
authors.lastname: Fiaschi
authors.forename: Alberto
authors.initials: A
authors.lastname: Beltramello
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D003071:Cognition; D004558:Electric Stimulation / Q000379:methods*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D014110:Touch / Q000502:physiology