title: Distinct vestibular effects on early and late somatosensory cortical processing in humans.
abstract: In non-human primates several brain areas contain neurons that respond to both vestibular and somatosensory stimulation. In humans, vestibular stimulation activates several somatosensory brain regions and improves tactile perception. However, less is known about the spatio-temporal dynamics of such vestibular-somatosensory interactions in the human brain. To address this issue, we recorded high-density electroencephalography during left median nerve electrical stimulation to obtain Somatosensory Evoked Potentials (SEPs). We analyzed SEPs during vestibular activation following sudden decelerations from constant-velocity (90°/s and 60°/s) earth-vertical axis yaw rotations and SEPs during a non-vestibular control period. SEP analysis revealed two distinct temporal effects of vestibular activation: An early effect (28-32ms post-stimulus) characterized by vestibular suppression of SEP response strength that depended on rotation velocity and a later effect (97-112ms post-stimulus) characterized by vestibular modulation of SEP topographical pattern that was rotation velocity-independent. Source estimation localized these vestibular effects, during both time periods, to activation differences in a distributed cortical network including the right postcentral gyrus, right insula, left precuneus, and bilateral secondary somatosensory cortex. These results suggest that vestibular-somatosensory interactions in humans depend on processing in specific time periods in somatosensory and vestibular cortical regions.
authors.affiliation: Laboratoire de Recherche en Neuroimagerie (LREN), Department of Clinical Neuroscience, Lausanne University and University Hospital, Lausanne, Switzerland; Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Pfeiffer
authors.affiliation: Department of Psychology, University of Amsterdam, Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: van Elk
authors.affiliation: Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
authors.forename: Fosco
authors.initials: F
authors.lastname: Bernasconi
authors.affiliation: Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Department of Neurology, University Hospital Geneva, Switzerland. Electronic address: olaf.blanke@epfl.ch.
authors.forename: Olaf
authors.initials: O
authors.lastname: Blanke
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012399:Rotation; D015398:Signal Transduction / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000502:physiology*; D055815:Young Adult
keywords: EEG; Electrical neuroimaging; Multisensory processing; Somatosensory cortex; Somatosensory evoked potentials; Vestibular system