Understanding and predicting the intentions of others through limb movements are vital to social interaction. The processing of biological motion is unique from the processing of motion of inanimate objects. Presently, there is controversy over whether visual consciousness of biological motion is regulated by visual attention. In addition, the neural mechanisms involved in biological motion-related visual awareness are not known. In the current study, the relationship between visual awareness (aware vs unaware), represented by a point-light walker and biological-motion-based attention, manipulated by a difference in congruence (congruent, incongruent) between the direction of a pre-cue and that of biological motion was explored. The neural mechanisms involved in processing the stimuli were explored through electroencephalography. Both early (50-150 ms, 100-200 ms, and 174-226 ms after target presentation) and late (350-550 ms after target presentation) awareness-related neural processings were observed during a biological motion-based congruency task. Early processing was localized to occipital-parietal regions, such as the left postcentral gyrus, the left middle occipital gyrus, and the right precentral gyrus. In the 174-226-ms window, the activity in the occipital region was gradually replaced by activity in the parietal and frontal regions. Late processing was localized to frontal-parietal regions, such as the right dorsal superior frontal gyrus, the left medial superior frontal gyrus, and the occipito-temporal regions. Congruency-related processing occurred in the 246-260-ms window and was localized to the right superior occipital gyrus. In summary, due to its complexity, biological motion awareness has a unique neural basis.
Keywords: biological motion; event related potential (ERP); exogenous attention; visual consciousness.
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