Monetary reward suppresses anterior insula activity during social pain

How Distributed Subcortical Integration of Reward and Threat May Inform Subsequent Approach-Avoidance Decisions

Healthy and successful living involves carefully navigating rewarding and threatening situations by balancing approach and avoidance behaviors. Excessive avoidance to evade potential threats often leads to forfeiting potential rewards. However, little is known about how reward and threat information is integrated neurally to inform approach or avoidance. In this preregistered study, participants (N behavior = 31, 17F; N MRI = 28, 15F) made approach-avoidance decisions under varying reward (monetary gains) and threat (electrical stimulations) prospects during functional MRI scanning. In contrast to theorized parallel subcortical processing of reward and threat information before cortical integration, Bayesian multivariate multilevel analyses revealed subcortical reward and threat integration prior to indicating approach-avoidance decisions. This integration occurred in the ventral striatum, thalamus, and bed nucleus of the stria terminalis (BNST). When reward was low, risk-diminishing avoidance decisions dominated, which was linked to more positive tracking of threat magnitude prior to indicating avoidance than approach decisions. In contrast, the amygdala exhibited dual sensitivity to reward and threat. While anticipating outcomes of risky approach decisions, we observed positive tracking of threat magnitude within the salience network (dorsal anterior cingulate cortex, thalamus, periaqueductal gray, BNST). Conversely, after risk-diminishing avoidance, characterized by reduced reward prospects, we observed more negative tracking of reward magnitude in the ventromedial prefrontal cortex and ventral striatum. These findings shed light on the temporal dynamics of approach-avoidance decision-making. Importantly, they demonstrate the role of subcortical integration of reward and threat information in balancing approach and avoidance, challenging theories positing predominantly separate subcortical processing prior to cortical integration.

Changed resting-state connectivity of anterior insular cortex affects subjective pain reduction after knee arthroplasty: A longitudinal study

The mechanism of chronic knee osteoarthritis (OA) pain and postoperative pain due to knee arthroplasty has not been elucidated. This could be involved neuroplasticity in brain connectivity. To clarify the mechanism of chronic knee OA pain and postoperative pain, we examined the relationship between resting-state functional connectivity (rs-FC) and clinical measurements in knee OA before and after knee arthroplasty, focusing on rs-FCs with the anterior insular cortex (aIC) as the key region. Fifteen patients with knee OA underwent resting-state functional magnetic resonance imaging and clinical measurements shortly before and 6 months after knee arthroplasty, and 15 age- and sex-matched control patients underwent an identical protocol. Seed-to-voxel analysis was performed to compare the clinical measurements and changed rs-FCs, using the aIC as a seed region, between the preoperative and postoperative patients, as well as between the operative and control patients. In preoperative patients, rs-FCs of the aIC to the OFC, frontal pole, subcallosal area, and medial frontal cortex increased compared with those of the control patients. The strength of rs-FC between the left aIC and right OFC decreased before and after knee arthroplasty. The decrease in rs-FC between the left aIC and right OFC was associated with decreased subjective pain score. Our study showed a correlation between longitudinally changed rs-FC and clinical measurement before and after knee arthroplasty. Rs-FC between the aIC and OFC have the potential to elucidate the mechanisms of knee OA pain and postoperative pain due to knee arthroplasty.

The effects of social exclusion on distributive fairness judgements and cooperative behaviour

In this article, we investigate how being socially excluded (vs. included) affects people's distributive fairness judgements and their willingness to cooperate with others in subsequent interactions. For this purpose, we conducted three experiments in which we assessed individual differences in having experienced being socially excluded (Experiment 1, N = 164), and manipulated social exclusion (Experiment 2, N = 120; Experiment 3, N = 492). We studied how this impacted fairness judgements of three different outcome distributions (disadvantageous inequality, advantageous inequality, and equality) both within-participants (Experiments 1 and 2) and between-participants (Experiment 3). To assess behavioural consequences, we then also assessed participants' cooperation in a social dilemma game. Across the three experiments, we consistently found that social exclusion impacted fairness judgements. Compared to inclusion, excluded participants judged disadvantageous inequality as more unfair and advantageous inequality as less unfair. Moreover, compared to socially included participants, socially excluded participants were more willing to cooperate after experiencing advantageous rather than disadvantageous inequality, and feelings of acceptance served as a mediator in these associations.

The dual facilitatory and inhibitory effects of social pain on physical pain perception

Pain is a multi-dimensional phenomenon that encompasses both physical pain experienced physiologically and social pain experienced emotionally. The interactions between them are thought to lead to increased pain load. However, the effect of social pain on physical pain perception during interactions remains unclear. Four experiments were conducted merging physical and social pains to examine the behavioral pattern and neural mechanism of the effect of social pain on physical pain perception. Seemingly paradoxical effects of social pain were observed, which both facilitated and inhibited physical pain perception under different attention orientations. Brain imaging revealed that the posterior insula encoded the facilitatory effect, whereas the frontal pole engaged in the inhibitory effect. At a higher level, the thalamus further modulated both processes, playing a switch-like role under different concern statuses of social pain. These results provide direct evidence for the dual-pathway mechanism of the effect of social pain on physical pain.

Excluded and myopic: Social exclusion increases temporal discounting

Social exclusion is a painful yet ubiquitous experience that modulates affect, behavior, and cognition. Decision-making is an essential cognitive ability that some forms of it are altered following social exclusion. However, how intertemporal decision-making is influenced by social exclusion is scarcely studied. Here, using Future Life Alone paradigm we demonstrated that experiencing social exclusion increases temporal discounting. We further tested whether the increased temporal discounting is mediated by either time perception or risk-taking. Our results revealed that although time perception is influenced by social exclusion, neither time perception nor risk-taking mediated the changes in temporal discounting. Our results are providing further evidence corroborating that social exclusion evokes cognitive deconstruction and therefore alters temporal discounting.

The different role of trait empathy and state social exclusion empathy on subsequent feelings about gambling outcome：Evidence from event-related potentials and time-frequency decompositions

Empathy plays an essential role in determining how we understand and respond to others' emotional experiences. Previous studies have mainly focused on the influencing factors of physical pain and monetary loss empathy, as well as on their effects on subsequent feelings. However, little is known about social pain empathy and its influence on subsequent feelings, and the role of personal trait empathy. In this study, we performed Cyberball Games and gambling tasks to explore the effect of social exclusion empathy on subsequent feelings for gambling outcomes (others' losses and gains) by analyzing the brain activity of excluded and non-excluded players at the gambling outcome feedback stage. It was found that both feedback-related negativity (FRN) and theta-band oscillatory are more negative for loss outcome than gain for the excluded players, while these effects cannot be found for the non-excluded players. Furthermore, we only observed a larger P300 amplitude in the gain outcome than that of loss, regardless of the players' role. More interestingly, we found state social pain empathy is negatively correlated with the d-FRN amplitude under non-excluded conditions, while trait empathy is positively correlated with P300 amplitude regardless of the players' role. These results provide insight into the different roles of state social pain empathy and trait empathy on subsequent gambling outcomes. Furthermore, different from previous studies, the current results show that d-FRN could reflect the state empathy discrepancy rather than the biomarker of state empathy.

EEG alpha and theta signatures of socially and non-socially cued working memory in virtual reality

In this preregistered study (https://osf.io/s4rm9) we investigated the behavioural and neurological [electroencephalography; alpha (attention) and theta (effort)] effects of dynamic non-predictive social and non-social cues on working memory. In a virtual environment realistic human-avatars dynamically looked to the left or right side of a table. A moving stick served as a non-social control cue. Kitchen items were presented in the valid cued or invalid un-cued location for encoding. Behavioural findings showed a similar influence of the cues on working memory performance. Alpha power changes were equivalent for the cues during cueing and encoding, reflecting similar attentional processing. However, theta power changes revealed different patterns for the cues. Theta power increased more strongly for the non-social cue compared to the social cue during initial cueing. Furthermore, while for the non-social cue there was a significantly larger increase in theta power for valid compared to invalid conditions during encoding, this was reversed for the social cue, with a significantly larger increase in theta power for the invalid compared to valid conditions, indicating differences in the cues' effects on cognitive effort. Therefore, while social and non-social attention cues impact working memory performance in a similar fashion, the underlying neural mechanisms appear to differ.

Social exclusion modulates neural dynamics of monetary and social reward processing in young adult females

Evidence suggests that social exclusion increases one's sensitivity to monetary and social rewards. However, whether and how social exclusion modulates the neural dynamics of reward processing remains unknown. The current study aimed to address this gap by systematically investigating the differential influences of social exclusion on various stages of monetary and social reward processing. Forty-five female participants were recruited, and the Cyberball game was used to manipulate social exclusion. To disentangle the anticipatory and consummatory stages of monetary and social reward processing, we recorded event-related potentials during two incentive delay tasks, one with a monetary reward and one with a social reward. The results showed that during the anticipatory stage, a larger contingent negative variation was observed for the exclusion group than for the inclusion group, regardless of reward type. During the consummatory stage, although the reward-related positivity was larger in the exclusion group than in the inclusion group, this difference was only observed for the social, and not monetary, reward feedback. These findings advance our understanding of the relationship between social exclusion and reward processing and suggest that while social exclusion might exert comparable enhancement effect for monetary and social reward processing during the anticipatory stage, it exerts a specific enhancement effect for social reward processing during the consummatory stage.

Does losing money truly hurt? The shared neural bases of monetary loss and pain

Both monetary loss and pain have been studied for decades, but evidence supporting the relationship between them is still lacking. We conducted a meta‐analysis to explore the overlapping brain regions between monetary loss and pain, including physical pain and social pain. Regardless of the type of pain experienced, activation of the anterior insula was a shared neural representation of monetary loss and pain. The network representation pattern of monetary loss was more similar to that of social pain than that of physical pain. In conclusion, our research provided evidence of the common neural correlates of monetary loss and pain.

Task- and Rest-based Functional Brain Connectivity in Food-related Reward Processes among Healthy Adolescents

It is known that the nucleus accumbens, orbitofrontal cortex and insula play a role in food-related reward processes. Although their interconnectedness would be an ideal topic for understanding food intake mechanisms, it nevertheless remains unclear especially in adolescent. Therefore, this study aims to investigate the effect of hunger on functional connectivity in healthy adolescents using task- and rest-based imaging. Fifteen participants underwent two MRI sessions, pre-lunch (hunger) and post-lunch (satiety), including food cue task and resting-state. During task- and rest-based imaging, functional connectivity was greater when hungry as opposed to satiated between the right posterior insula/nucleus accumbens, suggesting involvement of salient interoceptive stimuli signals. During task-based imaging, an increase was observed in functional connectivity when hungry as opposed to satiated between the medial and lateral orbitofrontal cortex which contributes to the perception of food deprivation as a frustration. A decrease was identified when hungry as opposed to satiated in functional connectivity in the right anterior orbitofrontal/accumbens and posterior insula/medial orbitofrontal cortices reflecting suppression of the affective and sensorial information. Conversely, functional connectivity was increased during aversive stimuli between the right medial orbitofrontal cortex and right posterior insula when hungry as opposed to satiated. This suggests that the value of valence could occur in the shift in connectivity between these two regions. In addition, during rest-based imaging, a left-sided lateralization was reported (accumbens/lateral orbitofrontal and accumbens/posterior insula) when hungry as opposed to satiated which may represent changes in internal state due to focus on the benefit of an upcoming meal.

Altered Resting-State Connectivity with Pain-Related Expectation Regions in Female Patients with Severe Knee Osteoarthritis

Purpose

Expectation affects pain experience in humans. Numerous studies have reported that pre-stimulus activity in the anterior insular cortex (aIC), together with prefrontal and limbic regions, integrated pain intensity and expectations. However, it is unclear whether the resting-state functional connectivity (rs-FC) between the aIC and other brain regions affects chronic pain. The purpose of this study was to examine the rs-FC between the aIC and the whole brain regions in female patients with severe knee osteoarthritis (OA).

Patients and Methods

Nineteen female patients with chronic severe knee OA and 15 matched controls underwent resting-state functional magnetic resonance imaging. We compared the rs-FC from the aIC seed region between the two groups. A disease-specific measurement of knee OA was performed.

Results

The aIC showed stronger rs-FC with the right orbitofrontal cortex (OFC), subcallosal area, and bilateral frontal pole compared with controls. The strength of rs-FC between the left aIC and the right OFC was positively correlated with the knee OA pain score (r = 0.49, p = 0.03). The strength of rs-FC between the right aIC and right OFC was positively correlated with the knee OA total score (r = 0.48, p = 0.036) and pain score (r = 0.46, p = 0.049). The OFC, subcallosal area, and frontal pole, together with the aIC, were activated during anticipation of pain stimulus. These areas have been reported as representative pain-related expectation regions.

Conclusion

This was the first study to show the stronger rs-FCs between the aIC and other pain-related expectation regions in female patients with severe knee OA. Female sex and preoperative pain intensity are risk factors of persistent postoperative pain after total knee arthroplasty. It is suggested that the functional relationship between pain-related expectation regions affects the formation of severe knee OA and persistent postoperative pain following total knee arthroplasty.

How is psychological stress linked to sleep quality? The mediating role of functional connectivity between the sensory/somatomotor network and the cingulo-opercular control network

How the functional connectivity of brain networks affects the relationship between psychological stress and sleep quality remains unclear. To better understand the associations between psychological stress, resting-state functional connectivity (RSFC), and sleep quality, we used the RSFC, Pittsburgh Sleep Quality Index (PSQI), and Psychosomatic Tension Relaxation Inventory (PSTRI) to investigate the relationship between psychological stress, sleep quality, and RSFC in four brain networks, the sensory/somatomotor (SM) network, cigulo-opercular control (CO) network, default mode (DM) network, and dorsal attention (DA) network, in a large healthy sample of 315 college students from Southwest University. Results showed that the brain functional connectivity in the SM, CO, DM, and DA networks was significantly correlated to sleep quality. Meanwhile, we also found that the brain functional connectivity between the SM and CO networks partially mediated the relationship between psychological stress and sleep quality, suggesting that psychological stress has an important effect on individuals' sleep quality, and increased functional connectivity between the SM and CO networks provides a neural basis for the association between psychological stress and poor sleep quality.

Imagery-induced negative affect, social touch and frontal EEG power band activity

Social touch seems to modulate emotions, but its brain correlates are poorly understood. Here, we investigated if frontal power band activity in the electroencephalogram (EEG) during aversive mental imagery is modulated by social touch from one's romantic partner and a stranger. We observed the highest theta and beta power when imaging alone, next so when being touched by a stranger, with lowest theta and beta activity during holding hands with the loved one. Delta power was higher when being alone than with a stranger or a partner, with no difference between the two. Gamma power was highest during the stranger condition and lower both when being alone and with the partner, while alpha power did not change as a function of social touch. Theta power displayed a positive correlation with electrodermal activity supporting its relation to emotional arousal. Attachment style modulated the effect of touch on the EEG as only secure but not insecure partner bonding was associated with theta power reductions. Because theta power was sensitive to the experimental perturbations, mapped onto peripheral physiological arousal and reflected partner attachment style we suggest that frontal theta power might serve as an EEG derived bio-marker for social touch in emotionally significant dyads.

Connectivity between the anterior insula and dorsolateral prefrontal cortex links early symptom improvement to treatment response

BACKGROUND

Early improvement (EI) following treatment with antidepressants is a widely reported predictor to the treatment response. This study aimed to identify the resting-state functional connectivity (rs-FC) and its related clinical features that link the treatment response at the time of EI.

METHODS

This study included 23 first-episode treatment-naive patients with MDD. After 2 weeks of antidepressant treatment, these patients received 3.0 Tesla resting-state functional magnetic resonance imaging scanning and were subgrouped into an EI group (N = 13) and a non-EI group (N = 10). Using the anterior insula (rAI) as a seed region, this study identified the rs-FC that were associated with both EI and the treatment response at week 12, and further tested the associations of the identified rs-FC with either the clinical features or the early symptom improvement.

RESULTS

Rs-FC between rAI and the left dorsolateral prefrontal cortex (dlPFC) was associated with EI (t₂₁ = -6.091, p = 0.022 after FDR correction for multiple comparisons). This rs-FC was also associated with an interaction between EI and the treatment response at the week 12 (t₂₁ = -5.361, p = 6.37e-5). Moreover, among the clinical features, this rs-FC was associated with the early symptom improvement in the insomnia, somatic symptoms, and anxiety symptoms, and these early symptom improvements were associated with the treatment response.

CONCLUSION

Rs-FC between the rAI and the left dlPFC played a crucial role in the early antidepressant effect, which linked the treatment response. The early treatment effect relating to rAI may represent an early symptom improvement in self-perceptual anxiety, somatic symptoms and insomnia.

Neural Basis of Professional Pride in the Reaction to Uniform Wear

Professional pride is a positive emotion that includes self-reflection or evaluation and attitude toward one’s own occupational group. Uniforms can encourage the wearer to have professional pride. The current study aimed to elucidate the neural basis of professional pride using an experimental task related to the self in uniform and functional magnetic resonance imaging (fMRI). The person-adjective matching task, in which a participant or other in uniform or casual wear was presented with positive and negative words, was used for scanning fMRI. Imaging data from 21 adults who had an occupation requiring a uniform were analyzed to identify the main and interaction effects of individual (self vs. other), clothes (uniform vs. casual wear), and valence (positive vs. negative). Identified brain activities were correlated with psychological scales including the Rosenberg Self-esteem Scale and Group Environment Questionnaire. Whole brain analyses found that the interaction between individual and clothes was present in multiple regions such as the right ventrolateral prefrontal cortex (VLPFC), left dorsolateral prefrontal cortex, left middle and inferior temporal gyri, left posterior superior temporal sulcus, right temporoparietal junction, left lingual gyrus, left calcarine cortex, right insula, left caudate, and right putamen. In particular, activities in the right VLPFC, left calcarine cortex, and right putamen in the self/uniform condition were positively correlated with several psychological scales. These results suggest that professional pride may be represented through multiple brain networks related to empathy, reward, and emotion regulation as well as the theory-of-mind network. The neural basis of professional pride is closely related to positive self-evaluation and group cohesion.

Bifidobacterium longum 1714™ Strain Modulates Brain Activity of Healthy Volunteers During Social Stress

OBJECTIVES

Accumulating evidence indicates that the gut microbiota communicates with the central nervous system, possibly through neural, endocrine, and immune pathways, and influences brain function. B. longum 1714™ has previously been shown to attenuate cortisol output and stress responses in healthy subjects exposed to an acute stressor. However, the ability of B. longum 1714™ to modulate brain function in humans is unclear.

METHODS

In a randomized, double-blinded, placebo-controlled trial, the effects of B. longum 1714™ on neural responses to social stress, induced by the "Cyberball game," a standardized social stress paradigm, were studied. Forty healthy volunteers received either B. longum 1714™ or placebo for 4 weeks at a dose of 1 × 10 cfu/d. Brain activity was measured using magnetoencephalography and health status using the 36-item short-form health survey.

RESULTS

B. longum 1714™ altered resting-state neural oscillations, with an increase in theta band power in the frontal and cingulate cortex (P < 0.05) and a decrease in beta-3 band in the hippocampus, fusiform, and temporal cortex (P < 0.05), both of which were associated with subjective vitality changes. All groups showed increased social stress after a 4-week intervention without an effect at behavioral level due to small sample numbers. However, only B. longum 1714™ altered neural oscillation after social stress, with increased theta and alpha band power in the frontal and cingulate cortex (P < 0.05) and supramarginal gyrus (P < 0.05).

DISCUSSION

B. longum 1714™ modulated resting neural activity that correlated with enhanced vitality and reduced mental fatigue. Furthermore, B. longum 1714™ modulated neural responses during social stress, which may be involved in the activation of brain coping centers to counter-regulate negative emotions.

Temptations of friends: adolescents' neural and behavioral responses to best friends predict risky behavior

Adolescents are notorious for engaging in risky, reward-motivated behavior, and this behavior occurs most often in response to social reward, typically in the form of peer contexts involving intense positive affect. A combination of greater neural and behavioral sensitivity to peer positive affect may characterize adolescents who are especially likely to engage in risky behaviors. To test this hypothesis, we examined 50 adolescents’ reciprocal positive affect and neural response to a personally relevant, ecologically valid pleasant stimulus: positive affect expressed by their best friend during a conversation about past and future rewarding mutual experiences. Participants were typically developing community adolescents (age 14–18 years, 48.6% female), and risky behavior was defined as a factor including domains such as substance use, sexual behavior and suicidality. Adolescents who engaged in more real-life risk-taking behavior exhibited either a combination of high reciprocal positive affect behavior and high response in the left ventrolateral prefrontal cortex—a region associated with impulsive sensation-seeking—or the opposite combination. Behavioral and neural sensitivity to peer influence could combine to contribute to pathways from peer influence to risky behavior, with implications for healthy development.

Does monetary reward operantly enhance pain sensitivity over time? An experiment in healthy individuals

Aim

Operant conditioning has long been believed to influence the pain experience through a psychological reward pathway. This study was formulated to test the hypothesis that pain sensitivity may be enhanced >3 months if a monetary reward works as a reinforcement.

Methods

Forty healthy subjects volunteered to participate in this study. The subjects repeatedly underwent pain testing via mechanical stimuli, and they rolled dice three (or six) times to gain money at the following five time points: baseline, three reinforcement sessions, and last session. The payoff was determined by roll of the dice. The subjects were instructed to roll the dice into a masked stand three times per session and informed that no one monitored the number of dice actually appeared. The subjects were also informed that they could roll the dice another three times when they reported strong pain during reinforcement sessions.

Results

The amount of individual payoff had significantly increased at last session compared with the values obtained at baseline; however, no changes were identified in terms of the pain ratings for mechanical stimuli during all sessions.

Conclusion

The results suggest that the psychological reward pathway does not always involve pain perception, and it is difficult to conclude whether pain sensitivity is operantly changed through the monetary reward in healthy individuals. Further investigation is required.

Effects of Rifaximin on Central Responses to Social Stress-a Pilot Experiment

Probiotics that promote the gut microbiota have been reported to reduce stress responses, and improve memory and mood. Whether and how antibiotics that eliminate or inhibit pathogenic and commensal gut bacteria also affect central nervous system functions in humans is so far unknown. In a double-blinded randomized study, 16 healthy volunteers (27.00 ± 1.60 years; 9 males) received either rifaximin (600 mg/day) (a poorly absorbable antibiotic) or placebo for 7 days. Before and after the drug intervention, brain activities during rest and during a social stressor inducing feelings of exclusion (Cyberball game) were measured using magnetoencephalography. Social exclusion significantly affected (p < 0.001) mood and increased exclusion perception. Magnetoencephalography showed brain regions with higher activations during exclusion as compared to inclusion, in different frequency bands. Seven days of rifaximin increased prefrontal and right cingulate alpha power during resting state. Low beta power showed an interaction of intervention (rifaximin, placebo) × condition (inclusion, exclusion) during the Cyberball game in the bilateral prefrontal and left anterior cingulate cortex. Only in the rifaximin group, a decrease (p = 0.004) in power was seen comparing exclusion to inclusion; the reduced beta-1 power was negatively correlated with a change in the subjective exclusion perception score. Social stress affecting brain functioning in a specific manner is modulated by rifaximin. Contrary to our hypothesis that antibiotics have advert effects on mood, the antibiotic exhibited stress-reducing effects similar to reported effects of probiotics (supported by NeuroGUT, a EU 7th Framework Programme ITN no. 607652; ClinicalTrials.gov identifier number NCT02793193).

How the brain reacts to social stress (exclusion) - A scoping review

OBJECTIVES

The Cyberball paradigm is often used to study social stress by exclusion/rejection. We aimed to review the existing neuroimaging literatures in order to provide an overview of the neurophysiological mechanisms of social exclusion.

METHOD

Literature search was conducted to identify neurophysiological studies that investigated effects of social exclusion on neural activity using the Cyberball game and the relevant influential factors on these effects.

RESULTS

In total, 42 studies using different neuroimaging methods were considered. Regions of the insula, anterior cingulate cortex, temporal and prefrontal cortex were activated to social exclusion. These neural activities were pronounced at latencies ranging from 200 to 400ms, and between 400 and 900ms. Influential factors were identified and categorized as intrinsic and extrinsic factors.

CONCLUSION

An integrated framework describing neural activities under social exclusion in terms of both, temporal and spatial processes is provided. Furthermore, the summary of influential intrinsic and extrinsic factors may help us to understand the diversity of the processes and may guide clinical therapy of stress related disorders.

Regional Gray Matter Volume Is Associated with Restrained Eating in Healthy Chinese Young Adults: Evidence from Voxel-Based Morphometry

Highlight

Participants were non-clinical young adults with different restrained eating levels.

We assessed relations of restrained eating (RE) with regional gray matter volume (rGMV).

High RE scores were related to larger GMV in specific areas related to reward.

High RE scores were also linked to less GMV in regions related to response inhibition.

Objective: Dieting is a popular method of weight control. However, few dieters are able to maintain initial weight losses over an extended period of time. Why do most restrained dieters fail to lose weight? Alterations in brain structures associated with restrained eating (RE) represent one potentially important mechanism that contributes to difficulties in maintaining weight loss within this group. To evaluate this contention, we investigated associations between intentional, sustained restriction of food intake to lose or maintain body weight, and regional gray matter volume (rGMV) within a large non-clinical young adult, sample.

Methods: Participants (150 women, 108 men) completed measures of RE and demographics prior to undergoing an MRI scan. Voxel-based morphometry (VBM) evaluated strengths of association between RE scores and rGMV.

Results: Higher RE levels corresponded to more rGMV in regions linked to risk of overeating and binge-eating including the left insula and orbitofrontal cortex (OFC). Conversely, RE had significant negative correlations with rGMV in the left and right posterior cingulum gyrus, regions linked to inhibitory control and potential risk for future weight gain.

Conclusions: Together, findings suggested individual differences in RE among young adults correspond to GMV variability in regions linked to overweight and obesity risk.

Social exclusion modulates priorities of attention allocation in cognitive control

Many studies have investigated how exclusion affects cognitive control and have reported inconsistent results. However, these studies usually treated cognitive control as a unitary concept, whereas it actually involved two main sub-processes: conflict detection and response implementation. Furthermore, existing studies have focused primarily on exclusion’s effects on conscious cognitive control, while recent studies have shown the existence of unconscious cognitive control. Therefore, the present study investigated whether and how exclusion affects the sub-processes underlying conscious and unconscious cognitive control differently. The Cyberball game was used to manipulate social exclusion and participants subsequently performed a masked Go/No-Go task during which event-related potentials were measured. For conscious cognitive control, excluded participants showed a larger N2 but smaller P3 effects than included participants, suggesting that excluded people invest more attention in conscious conflict detection, but less in conscious inhibition of impulsive responses. However, for unconscious cognitive control, excluded participants showed a smaller N2 but larger P3 effects than included participants, suggesting that excluded people invest less attention in unconscious conflict detection, but more in unconscious inhibition of impulsive responses. Together, these results suggest that exclusion causes people to rebalance attention allocation priorities for cognitive control according to a more flexible and adaptive strategy.