Studying brain visuo-tactile integration through cross-spectral analysis of human MEG recordings

An important aim in cognitive neuroscience is to identify the networks connecting different brain areas and their role in executing complex tasks. In this study, visuo-tactile tasks were employed to assess the functional correlation underlying the cooperation process between visual and tactile regions. MEG data were recorded from eight healthy subjects while performing a visual, a tactile, and a visuo-tactile task. To define regions of interest (ROIs), event-related fields (ERFs) were estimated from MEG data related to visual and tactile areas. The ten channels with the highest increase in ERF variance, moving from rest to task, were selected. Cross-spectral analysis was then performed to assess potential changes in the activity of the involved regions and quantify the coupling between visual and tactile ROIs. A significant decrease (p<0.01) in the power spectrum was observed during performing the visuo-tactile task compared to rest, both in alpha and beta bands, reflecting the activation of both visual and tactile areas during the execution of the corresponding tasks. Compared to rest, the coherence between visual and tactile ROIs increased during the visuo-tactile task. These observations seem to support the binding theory assuming that the integration of spatially distributed information into a coherent percept is based on transiently formed synchronized functional networks. © 2010 International Federation for Medical and Biological Engineering.