Although the human brain may have evolutionarily adapted to face-to-face communication, other modes of communication, e.g., telephone and e-mail, increasingly dominate our modern daily life. This study examined the neural difference between face-to-face communication and other types of communication by simultaneously measuring two brains using a hyperscanning approach. The results showed a significant increase in the neural synchronization in the left inferior frontal cortex during a face-to-face dialog between partners but none during a back-to-back dialog, a face-to-face monologue, or a back-to-back monologue. Moreover, the neural synchronization between partners during the face-to-face dialog resulted primarily from the direct interactions between the partners, including multimodal sensory information integration and turn-taking behavior. The communicating behavior during the face-to-face dialog could be predicted accurately based on the neural synchronization level. These results suggest that face-to-face communication, particularly dialog, has special neural features that other types of communication do not have and that the neural synchronization between partners may underlie successful face-to-face communication.

The neural mechanism of leader emergence is not well understood. This study investigated (i) whether interpersonal neural synchronization (INS) plays an important role in leader emergence, and (ii) whether INS and leader emergence are associated with the frequency or the quality of communications. Eleven three-member groups were asked to perform a leaderless group discussion (LGD) task, and their brain activities were recorded via functional near infrared spectroscopy (fNIRS)-based hyperscanning. Video recordings of the discussions were coded for leadership and communication. Results showed that the INS for the leader-follower (LF) pairs was higher than that for the follower-follower (FF) pairs in the left temporo-parietal junction (TPJ), an area important for social mentalizing. Although communication frequency was higher for the LF pairs than for the FF pairs, the frequency of leaderinitiated and follower-initiated communication did not differ significantly. Moreover, INS for the LF pairs was significantly higher during leader-initiated communication than during follower-initiated communications. In addition, INS for the LF pairs during leaderinitiated communication was significantly correlated with the leaders' communication skills and competence, but not their communication frequency. Finally, leadership could be successfully predicted based on INS as well as communication frequency early during the LGD (before half a minute into the task). In sum, this study found that leader emergence was characterized by highlevel neural synchronization between the leader and followers and that the quality, rather than the frequency, of communications was associated with synchronization. These results suggest that leaders emerge because they are able to say the right things at the right time.eadership is a ubiquitous feature of all social species, including human and nonhuman animals (1, 2). However, the neural mechanism of leader emergence is still not well-understood. Evolutionary theories suggest that, whereas both human and nonhuman animals have evolved tendencies to compete for dominance over access to survival-related resources (3-5), human leaders also play an important role in maintaining group cohesion (6). Thus, human leaders need to take into account not only their own needs but also the needs of their followers to facilitate cooperation among group members (7-9). Interestingly, recent imaging evidence indicates that the neural activities of two individuals are more synchronized when they perform a cooperative rather than a competitive task (10). Moreover, the level of interpersonal neural synchronization (INS) is closely associated with the level of understanding between partners (11). It is unknown, however, whether INS is involved in leader emergence.Previous evidence has shown that communication plays an important role in the increase of INS (12). However, the role of communication in leader emergence has been extensively debated. On the one hand, the so-called "babble" hypothesis postulates that the most t...

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The neural mechanism for the dyadic process of teaching is poorly understood. Although theories about teaching have proposed that before any teaching takes place, the teacher will predict the knowledge state of the student(s) to enhance the teaching outcome, this theoretical Prediction-Transmission hypothesis has not been tested with any neuroimaging studies. Using functional near-infrared spectroscopy-based hyperscanning, this study measured brain activities of the teacher-student pairs simultaneously. Results showed that better teaching outcome was associated with higher time-lagged interpersonal neural synchronization (INS) between right temporal-parietal junction (TPJ) of the teacher and anterior superior temporal cortex (aSTC) of the student, when the teacher's brain activity preceded that of the student. Moreover, time course analyses suggested that such INS could mark the quality of the teaching outcome at an early stage of the teaching process. These results provided key neural evidence for the Prediction-Transmission hypothesis about teaching, and suggested that the INS plays an important role in the successful teaching.

Accurate and imperceptible monitoring of electrophysiological signals is of primary importance for wearable healthcare. Stiff and bulky pregelled electrodes are now commonly used in clinical diagnosis, causing severe discomfort to users for long-time using as well as artifact signals in motion. Here, we report a ~100 nm ultra-thin dry epidermal electrode that is able to conformably adhere to skin and accurately measure electrophysiological signals. It showed low sheet resistance (~24 Ω/sq, 4142 S/cm), high transparency, and mechano-electrical stability. The enhanced optoelectronic performance was due to the synergistic effect between graphene and poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), which induced a high degree of molecular ordering on PEDOT and charge transfer on graphene by strong π-π interaction. Together with ultra-thin nature, this dry epidermal electrode is able to accurately monitor electrophysiological signals such as facial skin and brain activity with low-motion artifact, enabling human-machine interfacing and long-time mental/physical health monitoring.

BackgroundPsychological distress (e.g., depression and anxiety) has been regarded as the main cause of leaving work for people living with HIV/AIDS (PLWHA) in workplaces. This study aims to explore the associations of functional social support (FSS) and psychological capital (PC) with depressive and anxiety symptoms among PLWHA employed full-time.MethodsThis cross-sectional study was performed in Liaoning, China, during the period of December 2010–April 2011. The Center for Epidemiologic Studies Depression Scale, the Zung Self-Rating Anxiety Scale, the Duke-UNC Functional Social Support Questionnaire, and the Psychological Capital Questionnaire were completed by PLWHA employed full-time. Structural equation modeling was used to test the proposed relationships between variables. Asymptotic and resampling strategies were performed to explore the mediating roles of PC and its components (self-efficacy, hope, optimism, resilience).ResultsOf 320 participants surveyed, 66.3% had depressive symptoms, and 45.6% had anxiety symptoms. Significant negative associations of FSS and PC with depressive and anxiety symptoms were revealed. PC (a*b = −0.209, BCa 95% CI: -0.293, -0.137, p < 0.05), hope (a*b = −0.103, BCa 95% CI: -0.192, -0.034, p < 0.05), and optimism (a*b = −0.047, BCa 95% CI: -0.106, -0.008, p < 0.05) significantly mediated the association between FSS and depressive symptoms. PC (a*b = −0.151, BCa 95% CI: -0.224, -0.095, p < 0.05) and self-efficacy (a*b = −0.080, BCa 95% CI: -0.158, -0.012, p < 0.05) significantly mediated the FSS-anxiety symptoms association.ConclusionsFSS and PC could help reduce depressive and anxiety symptoms among PLWHA employed full-time. PC fully mediates the associations of FSS with depressive and anxiety symptoms. In addition to enhancing FSS, PC development could be included in the prevention and treatment strategies for depressive and anxiety symptoms targeted at PLWHA employed full-time.

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