title: The attentional-relevance and temporal dynamics of visual-tactile crossmodal interactions differentially influence early stages of somatosensory processing.
abstract: BACKGROUND
  Crossmodal interactions between relevant visual and tactile inputs can enhance attentional modulation at early stages in somatosensory cortices to achieve goal-oriented behaviors. However, the specific contribution of each sensory system during attentional processing remains unclear. We used EEG to investigate the effects of visual priming and attentional relevance in modulating somatosensory cortical responses.
  
  
  METHODS
  Healthy adults performed a sensory integration task that required scaled motor responses dependent on the amplitudes of tactile and visual stimuli. Participants completed an attentional paradigm comprised of 5 conditions that presented sequential or concurrent pairs of discrete stimuli with random amplitude variations: 1) tactile-tactile (TT), 2) visual-visual (VV), 3) visual-tactile simultaneous (SIM), 4) tactile-visual delay (TVd), and 5) visual-tactile delay (VTd), each with a 100 ms temporal delay between stimulus onsets. Attention was directed to crossmodal conditions and graded motor responses representing the summation of the 2 stimulus amplitudes were made.
  
  
  RESULTS
  Results of somatosensory ERPs showed that the modality-specific components (P50, P100) were sensitive to i) the temporal dynamics of crossmodal interactions, and ii) the relevance of these sensory signals for behaviour.
  
  
  CONCLUSIONS
  Notably, the P50 amplitude was greatest in the VTd condition, suggesting that presentation of relevant visual information for upcoming movement modulates somatosensory processing in modality-specific cortical regions, as early as the primary somatosensory cortex (SI).
authors.affiliation: Department of Kinesiology, University of Waterloo 200 University Ave. W, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Popovich
authors.affiliation: Department of Kinesiology, University of Waterloo 200 University Ave. W, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: W Richard
authors.initials: WR
authors.lastname: Staines
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D013997:Time Factors; D055698:Touch Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: Attention; ERPs; crossmodal; event-related potentials; sensorimotor integration; somatosensory cortex; tactile; visual