Alpha and beta event-related synchronization as neural markers of self-other processing during sensorimotor coordination

Interpersonal synchrony requires continuously balancing internally generated timing predictions with externally driven adjustments to a partner's behavior. Neural oscillations in alpha and beta bands have been implicated in prediction processes during joint action, yet their role in self-other integration remains unclear, particularly across varying levels of partner adaptivity. Here, we examined event-related desynchronization and synchronization (ERD/ERS) in the alpha (8-12 Hz) and beta (15-25 Hz) bands during a sensorimotor synchronization task. 47 participants performed a finger-tapping task with a virtual partner (VP) whose temporal adaptivity was manipulated (non-adaptive, moderately adaptive, and overly adaptive), whilst EEG activity was recorded. Behavioral results revealed that asynchrony decreased with increasing VP adaptivity. Neurally, we observed alpha and beta ERS instead of the typical ERD locked to the taps. For taps that came before tones (taps pre-tones), ERS was most pronounced over fronto-central areas, resembling auditory activity, and was highest when tapping with a non-adaptive VP. The spatial topography thus suggests that ERS reflects inhibition of sensory prediction of upcoming tones, and its modulation suggests that tone prediction is more inhibited when the VP is non-adaptive. For taps occurring after the tones (taps post-tones), ERS was observed over motor areas, with higher ERS when interacting with a more adaptive VP, suggesting enhanced inhibition of self-generated motor activity during interaction with an adaptive VP. Across conditions, higher ERS was associated with higher asynchrony. Together, these findings reveal that audio-motor neural components modulate self-other integration and give insight into how the adaptivity of the partner modulates action prediction and self-other balance.