Information flow between interacting human brains: Identification, validation, and relationship to social expertise

Abstract

Social interactions are fundamental for human behavior, but the quantification of their neural underpinnings remains challenging. Here, we used hyperscanning functional MRI (fMRI) to study information flow between brains of human dyads during real-time social interaction in a joint attention paradigm. In a hardware setup enabling immersive audiovisual interaction of subjects in linked fMRI scanners, we characterize cross-brain connectivity components that are unique to interacting individuals, identifying information flow between the sender's and receiver's temporoparietal junction. We replicate these findings in an independent sample and validate our methods by demonstrating that cross-brain connectivity relates to a key real-world measure of social behavior. Together, our findings support a central role of human-specific cortical areas in the brain dynamics of dyadic interactions and provide an approach for the noninvasive examination of the neural basis of healthy and disturbed human social behavior with minimal a priori assumptions.

Keywords: fMRI; hyperscanning; joint attention.

Fig. 1.

Hardware environment and analysis routine for fMRI hyperscanning. (A) Illustration of the hyperscanning setup as implemented for the present studies. (B) Schematic overview of the analysis routine for the examination of information flow between interacting human brain systems in hyperscanned fMRI data. Letters correspond to the numbering of in-text analysis steps.

Fig. 2.

ICA components showing neural coupling only in interacting subjects typically cover the right TPJ. (A) Component 11 (discovery study). (B) Component 5 (replication study). See Figs. S1 and S2 for display of both full sets of components.