Neural Oscillatory Dynamics in Joint Action: Dissociable Roles of Entrainment and Beta Modulation in Self–Other Integration

Abstract

Temporal coordination is fundamental for human communication and collaboration, yet the underlying neural mechanisms remain poorly understood. Central to this process is self–other integration, defined here as the extent to which a partner is processed as self-relevant and incorporated into one's sensorimotor representations. Recent evidence suggests that beta-band oscillatory dynamics may provide a shared sensorimotor framework supporting such integration. Here, we leveraged an immersive virtual-reality body-swap illusion to experimentally manipulate the embodiment of a partner's hand during joint rhythmic action, thereby testing the sensitivity of oscillatory brain dynamics to distinct levels of self–other integration. Forty participants, paired into 20 dyads, performed a finger-tapping task while viewing either their partner's hand in first-person (1P) or second-person (2P) perspective, or their own hand in uncoupled control conditions. Electroencephalography hyperscanning demonstrated that both neural entrainment of low-frequency oscillations and beta modulation linked to partner-generated movements occurred in visually coupled conditions. However, only beta modulation was selectively enhanced when participants perceived their partner's hand from a 1P perspective. These findings suggest that while neural entrainment reflects a general mechanism for tracking a partner's rhythmic behavior, beta modulation specifically supports the integration of the other's effector into one's bodily representation.