Evoked Multisensory Cortical Representations During Unisensory Stimulation

Abstract: The primary aim of this study was to establish whether redintegrative effects can be revealed under conditions with complex sensory stimulation.  Specifically, would the cortical activity involved in the single-trial, passive encoding of a movie, be reactivated when subsequently exposed to a unisensory component of that movie, e.g. an audio- or visual-only segment?  High-density electrical neuroimaging analysis in the frequency domain was used to assist this aim.  The statistical comparisons revealed a greater number of oscillating neuronal regions across all frequency bands in participants who received audiovisual stimulation prior to unisensory exposure (compared to participants who experienced the same unisensory stimulus without prior audiovisual stimulation).   This difference between groups was significant in the alpha2 (right frontal lobe) and gamma (right frontal, sub-lobar and temporal lobes) frequencies during audio-only stimulation.    This enhanced cortical activity during unisensory stimulation suggests that participants were retrieving associated memory traces from their prior multisensory experience, although specific redintegrative effects could not be confirmed.