Oscillatory components of somatosensory-visual-interactions
Poster Presentation

Markus Bauer
F.C.Donders Centre, University of Nijmegen

Pascal Fries
F.C.Donders Centre, University of Nijmegen

     Abstract ID Number: 115
     Full text: Not available
     Last modified: March 21, 2005

Abstract
We investigated the neural correlates of visuo-tactile integration using MEG recordings. In a simple-reaction-time-task, visual checkerboard stimuli were presented to the left or right side of fixation and were accompanied, on half of the trials, by a tactile stimulus to the right index finger.
Unimodal tactile and visual stimuli reliably induced gamma-band (60 -100 Hz) activity over somatosensory and visual areas, respectively. Bimodal stimulation reduced reaction times. Correspondingly, bimodal stimulation led to an earlier and enhanced gamma-band activity over visual areas and over motor cortex and to an enhanced short latency visual evoked response over parieto-occipital areas. Even though visual stimulation induced spectral pertubations in several frequency bands, the effect of intersensory interaction was concentrated in the early and high-frequency part of the gamma-band.
Cross-modal enhancement of activity in early sensory areas as observed previously in BOLD measures might therefore be related to the observed enhancement of gamma-band activity. These findings may provide a basis for further studying the dynamic interactions between different sensory areas during multimodal integration.