The right temporoparietal junction during a cooperation dilemma: An rTMS study

Cooperation enhances interpersonal communication and nurtures society. However, efforts to socially cooperate may often evoke conflict. Individuals may selfishly pursue a greater reward or success by exploiting the efforts of other individuals or taking unnecessary risk to oneself. Such a cooperation dilemma is highly prevalent in real life; thus, it has been studied in various disciplines. Although published functional magnetic resonance imaging studies have shown the involvement of the right temporoparietal junction (TPJ) in resolving a dilemma through cooperation, a causal relationship between the two has rarely been explored. Hence, we investigated this issue by combining repetitive transcranial magnetic stimulation with a priority game task (modified snowdrift game). In this game task, participants and opponent players jointly faced a problem whereby their collaboration was anticipated to defuse the situation. This conflicted with a choice in the participant's self-interest that was more rewarding but risky. We further included conditions with and without explicit social cues using figures describing elderly/pregnant passengers in the game opponent's car, and measured participants' prosocial traits to examine any cue-induced effect as well as the personality-cooperation relationship, respectively. The cooperation ratio was not statistically different in both the no-cue and with-cue conditions between the sham stimulation and inhibitory continuous theta burst stimulation (cTBS). However, after cTBS, in the no-cue condition, the strength of the association between cooperation ratio and empathy traits decreased significantly. These results add to our knowledge about the right TPJ's role in social cognition, which may be extraordinarily complex. This topic is deserving of further examination

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

Neuroeconomics processes underlying decision-making in joint vs individual actions: a behavioral and EEG study on non-human primates

A hallmark of the successful evolution of our species could reside in the ability to optimize collective behavior in order to achieve goals otherwise unattainable by acting alone. Inter-individual motor coordination can be considered as a key feature of sharing actions with others. As much as advantageous though, acting together can also be costly since it requires special cognitive and motor skills. We know that non-human primates are able to coordinate their actions in a dyadic context by dynamically adapting their motor behavior in a way that favors inter-individual synchronization. However, this type of behavioral adaptation has been proved to entail a cost, which is evident in a reduction of successful monkeys’ performance when sharing actions for a common goal. In the recent years, the existence of internal models of the own and the other’s action has been hypothesized by several authors, but how these models are formed and coded at the neural level is still object of study. The currently most accredited hypothesis is that acting with others requires the ability to integrate one’s own and others’ action representations in a dyadic motor plan. In order to better understand the behavioral and neural underpinnings of sharing actions, we conducted three experiments. In the first part of this work (Experiment 1) we investigated whether, how and under which task conditions monkeys can improve their performance in a joint action task. To address these questions, we have investigated the influence of a pre-instructing “social cue” providing anticipatory information about action context (individual or joint). Our findings suggest that pre-instructing the action context increase the chances of dyadic success by establishing an optimal “kinematic setting” that ultimately facilitates inter-individual motor coordination. Moreover, we speculate that such joint performance improvement can be ascribe to a successful resort to a “we-representation”, possible only when the joint action is pre-cued. In the second part of this thesis (Experiment 2) we aimed at investigating monkeys’ ability to estimate the cost of acting together and to use this information to decide between acting alone or jointly with a partner. To this aim we trained two monkeys to choose between two possible goals, each associated to different action types (solo or together) and payoffs. Our findings suggest that their economic choice was not merely dictated by the reward offered but also by the action cost, whereby motor inter-individual coordination was evaluated as more demanding than individual action. In the third and final part (Experiment 3) we conducted dual neural recordings using electroencephalography (EEG) while the monkeys were working on the same task adopted in Experiment 2. Preliminary results demonstrate that monkeys’ response evoked by the two offers was modulated by the action type chosen or expected to be chosen by the partner. This provides, for the first time, evidence of the feasibility of studying neural correlates underlying value-based decision making in non-human primates by mean of EEG methods

Neural correlates of online cooperation during joint force production

During joint action, two or more persons depend on each other to accomplish a goal. This mutual recursion, or circular dependency, is one of the characteristics of cooperation. To evaluate the neural substrates of cooperation, we conducted a hyperscanning functional MRI study in which 19 dyads performed a joint force-production task. The goal of the task was to match their average grip forces to the target value (20% of their maximum grip forces) through visual feedback over a 30-s period; the task required taking into account other-produced force to regulate the self-generated one in real time, which represented cooperation. Time-series data of the dyad's exerted grip forces were recorded, and the noise contribution ratio (NCR), a measure of influence from the partner, was computed using a multivariate autoregressive model to identify the degree to which each participant's grip force was explained by that of their partner's, i.e., the degree of cooperation. Compared with the single force-production task, the joint task enhanced the NCR and activated the mentalizing system, including the medial prefrontal cortex, precuneus, and bilateral posterior subdivision of the temporoparietal junction (TPJ). In addition, specific activation of the anterior subdivision of the right TPJ significantly and positively correlated with the NCR across participants during the joint task. The effective connectivity of the anterior to posterior TPJ was upregulated when participants coordinated their grip forces. Finally, the joint task enhanced cross-brain functional connectivity of the right anterior TPJ, indicating shared attention toward the temporal patterns of the motor output of the partner. Since the posterior TPJ is part of the mentalizing system for tracking the intention of perceived agents, our findings indicate that cooperation, i.e., the degree of adjustment of individual motor output depending on that of the partner, is mediated by the interconnected subdivisions of the right TPJ

Social and Affective Neuroscience of Everyday Human Interaction

This Open Access book presents the current state of the art knowledge on social and affective neuroscience based on empirical findings. This volume is divided into several sections first guiding the reader through important theoretical topics within affective neuroscience, social neuroscience and moral emotions, and clinical neuroscience. Each chapter addresses everyday social interactions and various aspects of social interactions from a different angle taking the reader on a diverse journey. The last section of the book is of methodological nature. Basic information is presented for the reader to learn about common methodologies used in neuroscience alongside advanced input to deepen the understanding and usability of these methods in social and affective neuroscience for more experienced readers

Elements of the Brain Network Regulating Social Behavior and Vocal Communication in Nf1+/- Mice: Relevance to Developmental Language Disorders and Autism Spectrum Disorders

Indiana University-Purdue University Indianapolis (IUPUI)Communication is a vital tool used by humans to share information, coordinate behavior, and survive. However, the ability to communicate can become disrupted or remain absent in individuals with neurodevelopmental disorders: two prominent examples include autism spectrum disorders and developmental language disorders, found in nearly 2% and 10% of the population, respectively. Communication disorders are devastating to the autonomy and quality of life of affected individuals, but clinical solutions are limited due to the complex and often unknown neural etiology underlying these conditions. One known disorder with high incidence of disrupted communication is Neurofibromatosis type 1, the genetic disease caused by heterozygosity of the Ras GTPase-activating protein-coding gene NF1. Mice heterozygous for their ortholog of this gene (Nf1+/-) have been shown to recapitulate neuropsychiatric conditions seen in patients. Using a courtship trial paradigm as a model for testing communication, I have demonstrated that Nf1+/- male mice showed deficits in both courtship and non-courtship social behavior as well as a decrease in the number and duration of ultrasonic vocalizations (USVs). Immediate early gene (IEG) immunohistochemistry (IHC) in neurons of courtship-relevant brain regions revealed the Shell of the Nucleus Accumbens (NAcS) as a dysfunctional brain region in Nf1+/- mice compared to WT male mice following courtship trial. Optogenetic targeting of the Nucleus Accumbens (NAc) restored courtship social behaviors and USV number, but not USV duration or non-courtship gestural social behaviors, in Nf1+/- males. This study contributes to a preclinical foundation for understanding etiology of communication disorders in patients

Social and Affective Neuroscience of Everyday Human Interaction

This Open Access book presents the current state of the art knowledge on social and affective neuroscience based on empirical findings. This volume is divided into several sections first guiding the reader through important theoretical topics within affective neuroscience, social neuroscience and moral emotions, and clinical neuroscience. Each chapter addresses everyday social interactions and various aspects of social interactions from a different angle taking the reader on a diverse journey. The last section of the book is of methodological nature. Basic information is presented for the reader to learn about common methodologies used in neuroscience alongside advanced input to deepen the understanding and usability of these methods in social and affective neuroscience for more experienced readers

Interactive brains:How infant cognition interacts with the dynamic social world

Research taking a cognitive neuroscience approach has shed light on social cognition during infancy. These studies have provided invaluable knowledge about how infants process social information, but a number of concepts regarding infant social cognition are often discussed based on research utilising rigidly controlled experimental paradigms where the role of infants is typically passive as an observer of stimuli. Increasing evidence suggests differences between the social cognitive processes that occurs when we act as observers of others (a ‘third-person’ perspective) and the processes that emerge when we are actively engaging with other people in an interactional context (a ‘second-person’ perspective) (e.g., Redcay and Schilbach, 2019; Siposova & Carpenter, 2019). Accordingly, there has been a growing recognition that we need a ‘second-person’ perspective, as compared to conventional “third-person” approach. The aim of the current thesis is to explore the interplay between infant cognition and the social world surrounding them, by moving research settings to a more naturalistic and dynamic one where infants are positioned as part of interaction. Towards this goal, Study 1 (Chapter 2) reviewed the current progress of “second-person” neuroscience research to evaluate the validity and robustness of simultaneous dual brain scanning techniques, often referred to as hyperscanning. The review identified large heterogeneity in reported effect sizes between published studies, suggesting the need to improve comparability of research, such as establishing standardised methods or promoting open science practices including code and data sharing to achieve higher reproducibility. This thesis then turned to research using various techniques from a conventional screen-based paradigm to a more dynamic setting, with the aim of building a stable platform towards second-person cognitive neuroscience approaches that investigate infant cognition while the infant actively interacts with other people. Study 2 (Chapter 3) explored how infants encode information differently from two adults who give gaze cues to a target object with different levels of accuracy. Whilst the study utilised a conventional event-related potential paradigm using screen-based stimuli, this paradigm could be adapted to enable future studies to investigate how infants’ social cognitive ability to discriminate reliable and unreliable informants can inform their subsequent behaviour observed in a social interactional behavioural task. Study 3 (Chapter 4) moved towards the use of more dynamic video stimuli and explored the neural processing of unexpected events. The study identified challenges in using dynamic perceptual inputs as stimuli. Study 4 (Chapter 5) transitioned into more naturalistic social contexts and analysed infant cognition while 10-month-old infants were faced with an adult demonstrating novel object labels in a live interaction. The study not only showed the feasibility of second-person neuroscientific research with infant participants, but also advanced our knowledge about infant word learning a step further, and demonstrated the trajectory from the encoding of semantic word information to its consolidation as knowledge. Study 5 (Chapter 6) also utilised a naturalistic interactional setting where infants were able to actively engage in a social task with an experimenter in a live manner, and aimed to identify systematic differences in neural activity between 9-month-old infants who make perseverative errors originally reported by Piaget (1954) and those who do not. This study was, to our knowledge, the first of its kind to validate the feasibility of utilising neurophysiological measures in this traditional interactive behavioural paradigm, in such a way that it does not interfere with the standard procedure. This thesis produced a series of studies which jointly demonstrate the potential for conducting research in a more dynamic setting that investigates infant social cognition taking a ‘second-person’ cognitive neuroscience approach to advance our knowledge about the intricate interaction between infant cognition, behaviour and the environment. We conclude this thesis by addressing the challenges of such an approach, to which we also attempt to propose solutions, as well as discussing future directions for the field