Two-brain states characterize within- and between-brain connectivity during intergenerational collaborative drawing

Area of Science:

• Neuroscience
• Social Cognition
• Human Interaction

Background:

• Social engagement synchronizes brain activity, typically studied using hyperscanning.
• Traditional methods assume symmetrical interactions and overlook dynamic brain states.
• Existing approaches obscure spatial and temporal dynamics of neural connectivity.

Purpose of the Study:

• To develop a data-driven method for quantifying within- and between-brain connectivity during dyadic collaboration.
• To identify recurrent two-brain states using sliding windows and Riemannian-geometry-based k-means clustering.
• To compare neural dynamics in same-generation versus intergenerational dyads during a collaborative drawing task.

Main Methods:

• Analyzed brain activity in 61 dyads (30 same-generation, 31 intergenerational) over 6 weeks during collaborative drawing.
• Applied sliding windows and Riemannian-geometry-based k-means clustering to identify distinct two-brain states.
• Investigated state specificity to real dyads and sensitivity to collaboration context and generation.

Main Results:

• Identified 7 recurrent two-brain states, with 3 specific to real dyads.
• One state demonstrated sensitivity to collaboration, characterized by altered within- and between-brain connectivity in intergenerational dyads.
• Intergenerational dyads exhibited prolonged periods of low-to-medium between-brain connectivity and prominent within-brain connectivity (bilateral IFG) during collaboration, linked to reduced turn-taking.
• No two-brain states showed longitudinal changes across sessions.

Conclusions:

• State-based analysis offers novel insights into neural dynamics beyond traditional methods.
• Findings highlight the interplay of within-brain and between-brain connectivity in social interaction.
• Intergenerational collaboration may involve distinct neural strategies compared to same-generation interaction.