Aging is associated with widespread deficits in theory of mind - the ability to infer others' mental and emotional states. Theory of mind is a complex construct, but age deficits are generally measured in a single domain, overlooking how older adults engage multiple theory of mind processes concurrently and spontaneously. The current work used neuroimaging to characterize the neural mechanisms associated with older adults' deficits in concurrent theory of mind judgments (awkwardness, deception) during a movie-watching task. 102 older adults (MAge = 73.5, SD = 6.6) and 110 young adults (MAge = 21.75, SD = 4.2) passively viewed a mockumentary television show while undergoing functional magnetic resonance imaging. Continuous ratings of awkwardness and deception were collected from an independent sample of young and older adults and used as parametric regressors. Across both judgment types, young adults had stronger activation in the dorsomedial prefrontal cortex, a region broadly implicated in theory of mind. Moreover, higher activation in the dorsomedial prefrontal cortex in response to deception and awkwardness was associated with older adults' higher theory of mind performance on an unrelated task. The brain activity involved in decoding concurrent mental states may provide unique insight into older adults' theory of mind deficits.

Social touch is necessary for the healthy development of trust. Although casual touch has been assumed to affect emotion and decision-making through a parallel mechanism, this has been challenging to test: How does touch affect learning to associate trust with people? A social version of the Iowa Gambling Task was designed by replacing cards with faces and associating these with tactile stimuli and economic outcomes. We measured how learned associations affected 1) choice preference during the Social Gambling Test (SGT), 2) face preferences in a subsequent oddball EEG task featuring SGT-stimuli; 3) choice adjustment in a final SGT with economic outcomes being reversed. Contrary to predictions, no initial bias toward touch-associated faces was observed. However, event-related potentials during the oddball task showed preferential processing toward disadvantageous/touch-associations, with early P3 component amplification. This effect presaged preference adjustments toward touch-associated faces in the second SGT when reward contingencies were reversed. Touch therefore did not directly produce trust but modified decision-making indirectly. We argue that tactile events and emotional outcomes are integrated within episodic memory and retrieved when risks require adaptation. We relate this interpretation to attachment theory, which likely highlights the relation between stressful uncertainty and tactile behavior.

This study aimed to explore associations between social isolation, loneliness, and hypothyroidism risk, and whether genetic susceptibility modifies these links. It enrolled 434,628 hypothyroidism-free participants from the UK Biobank. Social isolation was assessed via 3 dichotomous questions, loneliness via 2 revised UCLA Loneliness Scale questions, and hypothyroidism cases via hospital/death records. Hypothyroidism polygenic risk scores (PRSs) were calculated using related genetic loci, with Cox proportional hazards models for analysis. Over a median 12.3-year follow-up, 9,873 hypothyroidism cases occurred. Demographically adjusted models showed social isolation (HR = 1.25, 95% CI 1.17-1.33) and loneliness (HR = 1.38, 95% CI 1.27-1.50) linked to higher risk. After full adjustment, only loneliness remained significant (HR = 1.12, 95% CI 1.02-1.24), while social isolation's association became insignificant. No significant interactions between loneliness/social isolation or loneliness/PRS were found. Joint analysis revealed highest risk in those with high PRS and loneliness. Findings indicate loneliness, not social isolation, is an independent hypothyroidism risk factor, regardless of genetic susceptibility and other factors.

Risk-taking behavior varies across different life domains, yet neuroimaging research has primarily focused on financial incentives, thus limiting our understanding of the neural basis for domain-specific risk-taking. This study investigates whether neural correlates of risk-taking differ between financial and social incentive domains using functional magnetic resonance imaging (fMRI). Thirty-nine participants completed an adapted Balloon Analogue Risk Task with financial (monetary rewards) and social (gifts for children) incentive conditions. Behavioral data show that participants demonstrate less risk-seeking behavior in the social compared to financial condition. Neuroimaging results revealed both domain-general and domain-specific components of risk processing. A conjunction analysis of both incentive conditions identified a common neural network across both incentive types, including bilateral striatum, dorsal anterior cingulate cortex, and left insular cortex, supporting theories of domain-general risk processing mechanisms. Contrasting both reward conditions revealed significantly stronger activation in the right inferior parietal lobule during financial compared to social risk-taking, thus indicating a neural substrate for domain-specific risk preferences. These data might bridge the gap between behavioral evidence for domain-specific risk-taking and neuroimaging research, highlighting the importance of considering the type of incentives when studying risk behavior and its neural correlates.

Smiling plays a critical role in guiding behavior during social interactions from early in human ontogeny. The current study examined whether genetic variation in the oxytocin system is linked to individual differences in medial prefrontal cortex (mPFC) responses to smiles in human infants. Results show that genetic variation in CD38 (rs3796863), linked in prior work to variation in oxytocin release, is associated with enhanced mPFC responses when 7-month-old infants were viewing smiles, but not when viewing angry or fearful faces. These findings provide novel evidence that oxytocin-related genetic variability contributes to early-emerging differences in social brain function and support the view that variability in processing of affiliative signals is influenced by neurogenetic mechanisms from early in human ontogeny.

This study examined how interpersonal neural and autonomic similarity varies when dyads shift their decision-making (DM) orientation (between cognitive and emotional orientations) while evaluating moral dilemmas with a first- and third-person perspective. Thirteen dyads participated in two interactive conditions in which they jointly negotiated moral decisions (first vs third perspective), while their electrophysiological (EEG) and autonomic activity were continuously recorded. Before each interaction, participants' DM orientations were assessed, and dyads' orientation shift was classified according to whether one or both members changed orientation between the dilemmas (single-shift vs. dual-shift dyads). Interpersonal dissimilarity was quantified through Euclidean Distance (EuDist) across EEG frequency bands and Skin Conductance Level (SCL), Heart Rate (HR), HR Variability (HRV). Delta and gamma bands showed greater inter-brain dissimilarity in frontal than temporo-central and parieto-occipital regions, indicating region-specific recruitment for moral negotiation. Regarding orientation shift, dual-shift dyads displayed significantly higher gamma-band similarity compared to single-shift dyads, regardless of moral perspective. About perspective, autonomic results revealed greater inter-individual dissimilarity during first- than third-person perspective across SCL, HR, and HRV. Current findings suggest that DM orientation shift impacts neural coherence in dyads negotiating moral dilemmas (especially gamma band), while moral dilemmas perspective influences individual autonomic engagement in dyads.

Deficits in social behavior, such as reduced motivation and social avoidance, are key symptoms in several psychiatric disorders. Distinct modes of reward, such as drug and social, may rely on different dopamine release patterns in the mesolimbic pathway. We investigated the relationship between social reward behaviors and dopamine release elicited by phasic and tonic stimulation patterns in C57BL/6J mice. Cocaine (10 mg/kg, ip) was administered during dopamine recordings to assess drug-evoked dopamine release in relation to social reward behaviors. Social conditioned place preference was used to assess social reward, and in vivo fixed potential amperometry was used to measure nucleus accumbens dopamine release. Additional measures included the frequency and duration of social interactions during conditioning sessions. No relationship was found between baseline (pre-cocaine) dopamine and social place preference in either sex. However, in males, social place preference negatively correlated with cocaine-induced phasic dopamine release, indicating that increased social motivation was associated with a reduced phasic dopaminergic response to cocaine. In contrast, greater novel social interaction was associated with increased baseline dopamine elicited by tonic stimulations. These relationships were not observed in females. Overall, these findings suggest distinct, sex-dependent roles for phasic and tonic dopamine release in mediating social reward.

Individual differences in attachment classification reflect children's social expectations given early relational experiences with primary caregivers. When experiencing rejection - when affective needs are unmet - children can develop avoidant attachment strategies, including suppression of negative emotions and inhibition of observable reactions to adversity. A key aversive situation is social rejection, but how attachment differences affect neural responses to it is poorly understood. We combined functional MRI and the Cyberball paradigm to investigate responses to social rejection in 38 children (9-11 years) classified using the Child Attachment Interview. BOLD activation in the anterior cingulate cortex and right ventrolateral prefrontal cortex (vlPFC) was increased for events of social exclusion relative to inclusion. Dorsal to this effect, right vlPFC showed a negative correlation between exclusion-related BOLD activity and attachment dismissal, a continuous marker for avoidant attachment, reflecting greater vlPFC responses during inclusion (fair play) for avoidant attachment but unchanged responses to exclusion, suggesting increased regulatory monitoring during fair play in higher-dismissal children, rather than altered exclusion reactivity. This may be related to greater expressed worry about exclusion despite fair play in the inclusion condition. Our results suggest that avoidant attachment in children may be associated with impaired emotion regulation and greater expectation of rejection.

Intimate partner violence (IPV) impacts individuals, families, and wider society. Sensitivity to rejection is reliably associated with IPV use. Yet with IPV-users often demonstrating reduced emotional clarity, such sensitivity may not always be accessible to verbal reporting. Electroencephalography may circumvent this issue by capturing sensitivity to rejection at the neural level. Using event-related potentials, the neural processing of social exclusion has been explicated and is often linked to reductions in frontal slow wave (FSW) amplitude. This study examined FSW amplitude as elicited by the social exclusion game, Cyberball, to investigate the neural mechanisms of social exclusion processing in 43 fathers with and without histories of IPV use. We further investigate group differences in self-reported ostracism distress and emotional clarity across IPV-using and control fathers. IPV-using fathers displayed significantly lower exclusion evoked FSW amplitude, possibly reflecting stress-induced disruptions to mentalizing. Additionally, IPV-using fathers reported no significant differences in ostracism distress but increased difficulties in emotional clarity. Overall, findings suggest that IPV-using fathers display a profile of heightened neural sensitivity to social exclusion and a reduced ability to access their emotional states. These findings shed light on potential mechanisms of IPV to inform future research and interventions.

In an age flooded with pressure, lovers' resilience under stress and ability to creatively solve problems are highly valued. It is hoped that stress could become the crucible that forges lovers' creative sparks. Understanding the associations among romantic love, stress and advanced cognitive functions is highly topical. Using functional near-infrared spectroscopy (fNIRS) hyperscanning, the current study investigated dating couples' creative problem-solving performance under the effect of acute stress and the corresponding underlying neural mechanism. Results indicated that when faced with stressful situations, couples showed higher fluency and flexibility in creative problem-solving than those under non-stressful conditions. In addition, the couples showed greater synchronization in the frontopolar region under stress, with the direction from males to females, unveiling a distinct cooperative pattern of males leading and females receiving. Furthermore, interpersonal brain synchronization (IBS) mediated the effects that both salivary cortisol and heart rate level had on dating couples' creativity. These findings provide evidence supporting an integrative view for understanding relationships under adverse conditions, highlighting the different roles played by different genders in coping with stress.

Ethnic differences trigger immediate implicit stereotyping, potentially influencing intergroup interactions and reinforcing social inequality. Studies indicate that ethnic biases can reduce sensorimotor resonance toward out-group members, identifying the medial prefrontal cortex (mPFC) as part of a network involved in ethnic stereotyping regulation. The specific impact of ethnic biases on individuals' ability to coordinate actions with others and the role of mPFC in mediating in-/out-group interactions remain unclear. We investigated whether: i) interfering with mPFC activity modulates ethnic biases measured through affective misattribution procedure (AMP); ii) this interference affects coordination during a joint action task with ethnic out/in-group virtual partners. Continuous theta burst stimulation (cTBS) was used to interfere with the activity of mPFC (Experiments 1, 3) or left ventral Premotor Cortex (Experiment 2), and Vertex stimulation was included as active control site. Stimulating mPFC did not significantly affect either ethnic bias as measured through AMP nor individuals' interaction abilities when coordinating with out-/in-group members. However, participants' motor preparation times increased when interacting with an ethnic out-group compared to an in-group partner, regardless of the stimulation site. These findings highlight how ethnic membership influences social categorization and motor abilities during interpersonal interactions while limiting the role of mPFC in mediating inter-group motor coordination as measured in the present study.

Empathy is a fundamental component of social cognition, yet its influence on the neural processing of non-verbal cues in neurotypical populations remains insufficiently explored. Using EEG/ERPs, we examined empathy-dependent modulation of gesture recognition during a caption - gesture congruence task, manipulating face visibility in participants with high versus low Empathy Quotients (EQ). Participants, classified via two standardized empathy scales, viewed 800 gesture images preceded by short textual descriptions, while their EEG activity was recorded. High-EQ individuals exhibited faster reaction times, particularly when facial cues were absent, suggesting enhanced sensitivity to degraded social information. ERP analyses focused on the N250, N400, and late positivity (LP) components revealed empathy-related modulations, with high-EQ individuals showing amplified anterior N250 responses, associated with social cognition, emotional processing, and reward-related face recognition, whose amplitude increased linearly with empathy scores. Enhanced N400 and LP amplitudes further suggested more efficient semantic integration and decision confidence in high-EQ individuals. Source reconstruction identified greater activation in the posterior cingulate cortex, limbic structures, fusiform face area, superior temporal gyrus, and fronto-parietal mirror neuron networks, regions critical for social and non-verbal cue processing. These findings highlight a robust empathy-dependent network supporting spontaneous gesture interpretation and the flexible decoding of social meaning.

Evidence remained conflicting regarding how the prefrontal cortex supported decision-making abilities, particularly in patients with focal prefrontal cortex lesions. While damage to this region was known to impair executive functioning, the precise contribution of such deficits to decision-making performance - especially under varying levels of uncertainty - remained debated. Moreover, cognitive estimation processes, which were associated with logical reasoning and prefrontal involvement, had rarely been examined in relation to decision-making tasks. To clarify these associations, we administered a cognitive estimation task and the Iowa Gambling Task (IGT), alongside a battery of executive function tests, to 30 patients with focal prefrontal damage and 30 matched control subjects. Our results indicated that patients showed consistent impairment across executive functions, cognitive estimation, and decision-making under risk. Furthermore, correlation and regression analyses revealed that performance on executive tasks and cognitive estimation predicted IGT outcomes, particularly under risk conditions. Finally, voxel-based lesion-symptom mapping identified a bilateral prefrontal network - spanning ventromedial, dorsomedial, and dorsolateral regions - associated with impaired IGT performance. These findings suggested that the multidimensional nature of the IGT was associated with complex executive and inferential reasoning demands and implicated diverse patterns of frontal dysfunction beyond the ventromedial prefrontal cortex.