A neurodynamic model of inter-brain coupling in the gamma band

Area of Science:

• Neuroscience
• Computational Neuroscience
• Social Neuroscience

Background:

• Multiple-brain electroencephalography (EEG) hyperscanning reveals inter-brain coupling (IBC), a neural synchronization marker of social interaction.
• While theta-band IBC is well-modeled, gamma-band IBC (>30 Hz) lacks a clear biophysical explanation due to its fast dynamics.
• Intrabrain gamma activity is known to couple with lower frequencies via cross-frequency coupling (CFC).

Purpose of the Study:

• To provide a biophysical model for the emergence of gamma-band inter-brain coupling (gamma-IBC).
• To investigate the role of both intra-brain and inter-brain dynamics in generating gamma-IBC.
• To theoretically explain observed gamma-IBC phenomena in EEG-hyperscanning studies.

Main Methods:

• Utilized a Kuramoto model of four coupled oscillators, divided into two separate brain units.
• Simulated neural data by modulating inter-brain coupling in the theta band (between-units coupling).
• Adjusted intra-unit theta-gamma cross-frequency coupling (CFC) to assess its influence on gamma-IBC.

Main Results:

• Demonstrated that modulating theta-band inter-brain coupling and intra-brain theta-gamma CFC can generate gamma-band IBC.
• Provided a theoretical framework linking slower theta-band dynamics and intrabrain CFC to faster gamma-band inter-brain synchrony.
• Showcased the plausibility of CFC as a mechanism underlying gamma-IBC.

Conclusions:

• The study offers a novel biophysical explanation for gamma-band IBC observed in hyperscanning research.
• Highlights the critical role of intrabrain theta-gamma coupling in facilitating inter-brain synchrony at gamma frequencies.
• Establishes a theoretical foundation for understanding complex neural dynamics during social interactions.