Attention modulates event-related spectral power in multisensory self-motion perception

Humans integrate visual and physical (vestibular and proprioceptive) cues to motion during self-motion perception. Theta and alpha-band oscillations have been associated with the processing of visual motion (e.g. optic flow). Alpha and beta-band oscillations have been shown to be associated with sensory-motor processing (e.g. walking). The present study examined modulation of theta, alpha, and beta oscillations while participants made heading direction judgments during a passive self-motion task which required selective attention to one of the simultaneously presented visual or physical motion stimuli. Attention to physical (while ignoring visual) motion produced a different time course of changes in spectral power compared to attention to visual (while ignoring physical) motion. We observed weaker theta event-related synchronization (ERS), as well as stronger beta and later onset of alpha event-related desynchronization (ERD) in the attend-physical condition compared to the attend-visual condition. We observed individual differences in terms of ability to perform the task. Specifically, some participants were not able to ignore or discount the visual input when visual and physical heading direction was incongruent; this was reflected by similar event-related spectral power for both conditions. The results demonstrated a possible electrophysiological signature of the time course of 1) cue conflict (congruency effects), 2) attention to specific motion cues, and 3) individual differences in perceptual weighting of motion stimuli (high-vs. low-accuracy effects).