Brain-to-Brain Coupling in the Gamma-Band as a Marker of Shared Intentionality

Abstract

Cooperation and competition are two ways of social interaction keys to life in society. Recent EEG-based hyperscanning studies reveal that cooperative and competitive interactions induce an increase in interbrain coupling. However, whether this interbrain coupling effect is just a reflection of inter-subject motor coordination or can also signal the type of social interaction is unknown. Here, we show that behavioral coordination and social interaction type can be distinguished according to the frequency of oscillation in which the brains are coupled. We use EEG to simultaneously measure the brain activity of pairs of subjects, while they were performing a visual cue-target task in a cooperative and competitive manner. Behavioral responses were quasi-simultaneous between subject pairs for both competitive and cooperative conditions, with faster average response times for the competitive condition. Concerning brain activity, we found increased interbrain coupling in theta band (3-7 Hz) during cooperation and competition, with stronger coupling during competitive interactions. This increase of interbrain theta coupling correlated with a decrease in reaction times of the dyads. Interestingly, we also found an increase in brain-to-brain coupling in gamma band (38-42 Hz) only during cooperative interactions. Unlike the theta coupling effect, the gamma interbrain coupling did not correlate with dyads' reaction times. Taken together, these results suggest that theta interbrain coupling could be linked to motor coordination processes common to cooperative and competitive interactions, while gamma brain-tobrain coupling emerges as an electrophysiological marker of shared intentionality during cooperative interactions.

Elevated Inter-Brain Coherence Between Subjects With Concordant Stances During Discussion of Social Issues

“…Our investigation into the effects of social concordance on interbrain coherence has provided evidence in support of two primary conclusions: (1) that our results are largely in support of interbrain coupling at the gamma band as a biomarker for social concordance manifest here when subject pairs agreed on scenario issues, and (2) that patterns of IBC appear to be sensitive to informational context and content based on IBC variability between the different scenario issues. This study replicated results from previous studies implicating inter-brain gamma activity with core elements of social cognition that underlie social connectedness (Kinreich et al, 2017;Barraza et al, 2020). In our measures of social concordance, we found greater average IBC in agreeing over disagreeing subject pairs (Figure 2).…”

“…Our results are largely consistent with other reports on the relationship between inter-brain gamma activity and social connectedness. A recent study found that inter-brain synchrony in the gamma band was selectively increased between subjects that were playing cooperatively during a reaction time task but not during the competitive trials (Barraza et al, 2020). They found that transient increases in brainto-brain gamma activity during cooperation appeared just prior to and immediately following presentation of stimulus.…”

“…The gamma frequency band has been implicated of differential effects of cooperation vs. competition during a reaction time task. Inter-brain synchrony was selectively increased between pairs that were playing cooperatively, but not during the competitive trials (Barraza et al, 2020). These transient increases in brainto-brain gamma activity during cooperation appeared just prior to and immediately following presentation of the stimulus.…”

Relations between family cohesion and adolescent-parent’s neural synchrony in response to emotional stimulations

“…This interbrain phase synchrony index has been developed to measure whether the signals from the two interacting individuals are phase locked across time (Lachaux et al, 1999). In line with previous hyperscanning research ( Barraza et al, 2020), the band-pass ltering is applied to the EEG data of each segment of the parent's electrode (φ) and the adolescent's electrode (ψ) to obtain the EEG data of the frequency band of interest. The Hilbert transform is used to analyze the signals of φ and ψ poles in a speci c frequency band, extract phase and subtract, and get PLV of each epoch.…”

Combining neurophysiological and psychological indicators to understand individual and team cognition and decision-making

“…In neuroscience, research on shared cognition among dyads and small groups is captured by aggregating individual member's EEG-WL spectral analysis data (Waldman et al, 2015) wherein EEG-WL is a marker of the cognitive processing required to gather information and compare it to internal mental models. More recent work on neurophysiologic synchronies have now begun to capture the overlap in neural activity among multiple members in a team to capture how much overlap or difference there is in how members pay attention to, react, and process common information (Barraza et al, 2020;Dodel et al, 2020;.…”