Differential contribution of between and within-brain coupling to movement synchronization

Area of Science:

• Neuroscience
• Social Cognition
• Human Behavior

Background:

• The human brain connects regions for behavior.
• Social interactions involve coordinating activity between brains.
• Between-brain and within-brain coupling's role in movement synchronization is unclear.

Purpose of the Study:

• Investigate differential contributions of between-brain and within-brain coupling to movement synchronization.
• Examine coupling between the inferior frontal gyrus (IFG) and dorsomedial prefrontal cortex (dmPFC) during movement tasks.

Main Methods:

• Simultaneous functional near-infrared spectroscopy (fNIRS) in dyads performing 3D hand movements.
• Three conditions: back-to-back movement, free movement, and intentional synchronization.
• Analysis of behavioral synchrony and neural coupling (between-brain and within-brain).

Main Results:

• Behavioral synchrony was highest during intentional synchronization.
• Between-brain coupling in IFG and dmPFC occurred during free and intentional synchronization, but not back-to-back movement.
• Between-brain coupling predicted intentional synchrony; within-brain coupling predicted free movement synchronization.

Conclusions:

• Brain organization shifts during intentional synchronization, prioritizing between-brain networks for successful communication.
• Movement synchronization involves a transition from within-brain feedback to a two-brain feedback loop.
• Findings highlight the neural basis of interpersonal coordination and social interaction.