Two is better than one: The effects of strategic cooperation on intra- and inter-brain connectivity by fNIRS

Inter-brain synchronization during joint actions is a core question in social neuroscience, and the differential contribution of intra- and inter-brain functional connectivity has yet to be clarified along with the role of psychological variables such as perceived self-efficacy. The cognitive performance and the neural activation underlying the execution of joint actions were recorded by functional Near-Infrared imaging during a synchronicity game. An 8-channel array of optodes was positioned over the frontal and prefrontal regions. During the task, the dyads received reinforcing feedback that was experimentally manipulated to induce adoption of common strategies. Intra- and inter-brain connectivity indices were computed along with an inter-brain/intra-brain connectivity index (ConIndex). Finally, correlation analyses were run to assess the relationship between behavioral and physiological levels. The results showed that the external feedback could modulate participant responses in both behavioral and neural components. After the reinforcing manipulation, there were faster response times and increased inter-brain connectivity, and ConIndex emerged primarily over the dorsolateral prefrontal cortex. Additionally, the presence of significant correlations between response times and inter-brain connectivity revealed that only the \ue2\u80\u9ctwo-players connection\ue2\u80\u9d may guarantee an efficient performance. The present study provides a significant contribution to the identification of intra- and inter-brain functional connectivity when social reinforcement is provided

Donate or receive? Social hyperscanning application with fNIRS

Recent research in social neuroscience has shown how prosocial behavior can increase perceived self-efficacy, perception of cognitive abilitites and social interactions. The present research explored the effect of prosocial behavior, that is giving a gift during an interpersonal exchange, measuring the hyperscanning among two brains. The experiment aimed to analyze the behavioral performance and the brain-to-brain prefrontal neural activity of 16 dyads during a joint action consisting in a cooperative game, which took place in a laboratory setting controlled by an experimenter, to play before and after a gift exchange. Two different types of gift exchange were compared: experiential and material. Functional Near Infrared Spectroscopy (fNIRS) was applied to record brain activity. Inter-brain connectivity was calculated before and after the gift exchange. In behavioral data, a behavioral performance increase was observed after gift exchange, with accuracy improvement and response times decrease. Regarding intra-brain analyses, an increase in oxygenated hemoglobin was detected, especially in the dorsolateral prefrontal cortex (DLPFC) in both donor and receiver; and in the dorsal part of the premotor cortex (DPMC) in the donor. Moreover, as regards the gift type, greater activation in the DPLFC emerged in both the donor and the receiver after receiving an experiential gift. Finally, the results of the inter-brain connectivity analysis showed that after gift exchange, the donor and receiver brain activity was more synchronized in the DPMC and Frontal Eye Fields (FEF) areas. The present study provides a contribution to the identification of inter-brain functional connectivity when prosocial behaviors are played out

Exploring the Connected Brain by fNIRS: Human-to-Human Interactions Engineering

Functional Near Infrared Spectroscopy (fNIRS) is a relatively new neuroimaging technique adequate and useful for exploring neural activity in social contexts involving human interactions. Compared to functional Magnetic Resonance Imaging (fMRI), fNIRS is easy-to-use safe, noninvasive, silent, relatively low cost and portable, and applicable to subjects of all ages, thus resulting in a good option for ecological studies involving humans in their real-life context. Moreover, by using hyperscanning technique, fNIRS allows recording the hemodynamic cerebral activity of two interacting subjects in an ecological context or during a shared performance. Thus, moving from a simple analysis about each subject\u2019s neural response during joint actions towards more complex computations makes possible to investigate brain synchrony, that is the if and how one\u2019s brain activity is related to that of another interacting partner simultaneously recorded. Here, we discuss how connectivity analyses, with respect to both time and frequency domain procedures, permitted to deepen some aspects of inter-brain synchrony in relation to emotional closeness, and to highlight how concurrent, cooperative actions can lead to interpersonal synchrony and bond construction

A gift for gratitude and cooperative behavior. Brain and cognitive effects

Recently, different psychological studies have been interested in identifying the factors that regulate the development and maintenance of long-lasting interpersonal and social relationships. Specifically, the present research explored the link between gift exchange, gratitude and cognitive effects. The behavioral performance and neural activity of 32 participants were recorded during a cooperative game to be played before and after gift exchange. Specifically, participants had to perform the task coupled with a dear friend. Half of the couples were asked to exchange a gift before the task performance; the other half was asked to exchange a gift halfway through the task performance. For hemodynamic brain responses, functional near-infrared spectroscopy was used. Results showed that an increase in cognitive performance occurred after the exchange of gifts, with improved accuracy and lower response times in task performance. Regarding hemodynamic responses, an increase in oxygenated hemoglobin was detected, especially in the dorsolateral prefrontal cortex following the gift exchange. Furthermore, it was observed that gift exchange before the beginning of the task increased the performance level. The present study provides a significant contribution to the identification of those factors that enable the increased cognitive performance based on cooperative relationships

Multimodal hyperscanning reveals that synchrony of body and mind are distinct in mother-child dyads

Hyperscanning studies have begun to unravel the brain mechanisms underlying social interaction, indicating a functional role for interpersonal neural synchronization (INS), yet the mechanisms that drive INS are poorly understood. The current study, thus, addresses whether INS is functionally-distinct from synchrony in other systems – specifically the autonomic nervous system and motor behavior. To test this, we used concurrent functional near-infrared spectroscopy - electrocardiography recordings, while N = 34 mother-child and stranger-child dyads engaged in cooperative and competitive tasks. Only in the neural domain was a higher synchrony for mother-child compared to stranger-child dyads observed. Further, autonomic nervous system and neural synchrony were positively related during competition but not during cooperation. These results suggest that synchrony in different behavioral and biological systems may reflect distinct processes. Furthermore, they show that increased mother-child INS is unlikely to be explained solely by shared arousal and behavioral similarities, supporting recent theories that postulate that INS is higher in close relationships

Quantification of inter-brain coupling: A review of current methods used in haemodynamic and electrophysiological hyperscanning studies

Hyperscanning is a form of neuroimaging experiment where the brains of two or more participants are imaged simultaneously whilst they interact. Within the domain of social neuroscience, hyperscanning is increasingly used to measure inter-brain coupling (IBC) and explore how brain responses change in tandem during social interaction. In addition to cognitive research, some have suggested that quantification of the interplay between interacting participants can be used as a biomarker for a variety of cognitive mechanisms aswell as to investigate mental health and developmental conditions including schizophrenia, social anxiety and autism. However, many different methods have been used to quantify brain coupling and this can lead to questions about comparability across studies and reduce research reproducibility. Here, we review methods for quantifying IBC, and suggest some ways moving forward. Following the PRISMA guidelines, we reviewed 215 hyperscanning studies, across four different brain imaging modalities: functional near-infrared spectroscopy (fNIRS), functional magnetic resonance (fMRI), electroencephalography (EEG) and magnetoencephalography (MEG). Overall, the review identified a total of 27 different methods used to compute IBC. The most common hyperscanning modality is fNIRS, used by 119 studies, 89 of which adopted wavelet coherence. Based on the results of this literature survey, we first report summary statistics of the hyperscanning field, followed by a brief overview of each signal that is obtained from each neuroimaging modality used in hyperscanning. We then discuss the rationale, assumptions and suitability of each method to different modalities which can be used to investigate IBC. Finally, we discuss issues surrounding the interpretation of each method

Drumming To Communicate Emotion: Dual-Brain Imaging Informs An Intervention In A Carceral Setting

Drumming is an ancient nonverbal communication modality for expression of emotion. However, there has been limited exploration of its possible applications in clinical settings. Further, the underlying neural systems engaged during live communication with drumming have not been identified. We investigated the neural response to live, natural communication of emotion via drumming using a novel dual-brain neuroimaging paradigm to discover its unique neurophysiological mechanisms related to drum behavior and cross-brain coherence, and as compared to talking. We then investigated the application of a drumming intervention in an incarcerated, halfway house population to characterize intervention feasibility, elucidate the phenomenology of social and emotional effects of group drumming, and identify its possible benefits for treatment engagement and community reintegration. For neural response investigation, hemodynamic signals were acquired using whole-head functional near infrared spectroscopy. Dyads of 36 subjects participated in two conditions, drumming and talking, alternating between “sending” (drumming or talking to partner) and “receiving” (listening to partner) in response to emotionally salient images from the International Affective Picture System. Results indicated that increased frequency and amplitude of drum strikes was behaviorally correlated with higher arousal and lower valence measures, and neurally correlated with temporoparietal junction (TPJ) activation in the listener. Contrast comparisons of drumming greater than talking also revealed neural activity in right TPJ. For the interventional investigation, a group drumming program was implemented once a week for eight weeks for incarcerated participants in a halfway house. Twenty-eight participants were randomized to either the drum group or treatment as usual. Interviews and a focus group were conducted to assess the experienced benefits of the group drumming intervention, and halfway house retention rates were compared across groups. Retention rate was significantly higher in the drum group than in the treatment as usual group. Qualitative analysis elicited three themes: group drumming 1) functions therapeutically as a method of coping with difficulty, 2) offers opportunity for connection through building relationship and experiencing communion in a setting where isolation is the norm, and 3) provides an environment for personal growth, particularly toward re-humanization and self-empowerment. Neural findings suggest that emotional content communicated by drumming engages right TPJ mechanisms in an emotionally and behaviorally sensitive fashion; interventional findings suggest significant therapeutic potential in social and emotional domains that can have quantifiable impact on recovery process. Together, findings suggest that drumming may provide access to neural mechanisms with known sensitivity to social and emotional conditions that facilitates therapeutic aims. Informed by this research, drumming may provide novel, effective clinical approaches for treating social-emotional psychopathology

The effects of interaction quality on neural synchrony during mother-child problem solving.

Understanding others is fundamental to interpersonal coordination and successful cooperation. One mechanism posited to underlie both effective communication and behavioral coordination is interpersonal neural synchrony. Although presumably foundational for children's social development, research on neural synchrony in naturalistic caregiver-child interactions is lacking. Using dual-functional near-infrared spectroscopy (fNIRS), we examined the effects of interaction quality on neural synchrony during a problem-solving task in 42 dyads of mothers and their preschool children. In a cooperation condition, mothers and children were instructed to solve a tangram puzzle together. In an individual condition, mothers and children performed the same task alone with an opaque screen between them. Wavelet transform coherence (WTC) was used to assess the cross-correlation between the two fNIRS time series. Results revealed increased neural synchrony in bilateral prefrontal cortex and temporo-parietal areas during cooperative as compared to individual problem solving. Higher neural synchrony during cooperation correlated with higher behavioral reciprocity and neural synchrony predicted the dyad's problem-solving success beyond reciprocal behavior between mothers and children. State-like factors, such as maternal stress and child agency during the task, played a bigger role for neural synchronization than trait-like factors, such as child temperament. Our results emphasize neural synchrony as a biomarker for mother-child interaction quality. These findings further highlight the role of state-like factors in interpersonal synchronization processes linked to successful coordination with others and in the long-term might improve the understanding of others

Real-Time Eye-to-Eye Contact Is Associated With Cross-Brain Neural Coupling in Angular Gyrus

Direct eye contact between two individuals is a salient social behavior known to initiate and promote interpersonal interaction. However, the neural processes that underlie these live interactive behaviors and eye-to-eye contact are not well understood. The Dynamic Neural Coupling Hypothesis presents a general theoretical framework proposing that shared interactive behaviors are represented by cross-brain signal coherence. Using functional near-infrared spectroscopy (fNIRS) adapted for hyper scanning, we tested this hypothesis specifically for neural mechanisms associated with eye-to-eye gaze between human participants compared to similar direct eye-gaze at a dynamic video of a face and predicted that the coherence of neural signals between the two participants during reciprocal eye-to-eye contact would be greater than coherence observed during direct eye-gaze at a dynamic video for those signals originating in social and face processing systems. Consistent with this prediction cross-brain coherence was increased for signals within the angular gyrus (AG) during eye-to-eye contact relative to direct eye-gaze at a dynamic face video (p < 0.01). Further, activity in the right temporal-parietal junction (TPJ) was increased in the real eye-to-eye condition (p < 0.05, FDR corrected). Together, these findings advance a functional and mechanistic understanding of the AG and cross-brain neural coupling associated with real-time eye-to-eye contact

Cooperative leadership in hyperscanning. Brain and body synchrony during manager-employee interactions

Recent advances in neurosciences permitted to extend the knowledge about brain functioning to the organizational field with a specific interest to leadership, with the extent to explore more proficient ways of managing. In the present research, through a hyperscanning paradigm, EEG and autonomic synchrony was explored during performance reviews to investigate if different leadership styles (partecipative vs. authoritative), could be associated with different dyadic engagement. Analysis involved coherence computation assessing the strenght of inter-brain and body synchrony, which revealed the presence of a higher emotional synchronization for both neural and bodily reactions mainly for partecipative style