Spatio-Temporal Dynamics of Oscillatory Brain Activity during the Observation of Actions and Interactions between Point-light Agents

Abstract

Predicting actions from nonverbal cues and using them to optimize one's response behavior (i.e., interpersonal predictive coding) is essential in everyday life social interaction. 39 participants watched two agents depicted by moving point-light stimuli while an electroencephalogram (EEG) was recorded. One well-recognizable agent performed either a communicative or an individual action. The second agent was either masked by a cloud of noise dots, or absent and replaced by noise dots, which participants had to differentiate. EEG amplitude and coherence analyses for theta, alpha and beta frequency bands revealed a dynamic pattern unfolding over time: Watching communicative actions was associated with enhanced coupling within medial anterior regions involved in social and mentalizing processes and with dorsolateral prefrontal activation indicating a higher deployment of cognitive resources. Trying to detect the masked agent without having seen communicative cues was related to enhanced coupling in posterior regions for social perception and visual processing. Observing an expected outcome was associated with increased motor system activation. Finally, when the masked agent was detected correctly, activation in posterior areas for visual processing and social cognition was increased. Taken together, our results demonstrate that it is crucial to consider the temporal dynamics of social interactions and of their neural correlates to better understand interpersonal predictive coding.