Auditory Processing under Steady State Visual Driving

Neuronal oscillations are considered crucial for information processing in the brain as they can potentially regulate information flow and dynamically bind different cortical and non-cortical regions. This MEG study investigated whether the effect of a transient sound was modulated by the phase of oscillations in the visual cortex. To induce steady state oscillations in the visual cortex, we presented subjects with continuous visual signals luminance-modulated at 4Hz or 10Hz. The transient sounds were presented locked to four phases of the periodic visual stimulus (i.e. 0, 1 2, , 3 4). We then investigated whether the effect of sound depends on the phase of the visual steady state activity by testing for the interaction between sound and visual phase. Conversely, we will investigate the effect of the sound processing on the visual steady state processing given the state of the visual cortex. The results from the two experiments (4Hz 10Hz) will be combined and compared. Based on recent neurophysiological evidence, we hypothesize that oscillations at different frequencies play distinct functional roles in multisensory integration