Hormonal reactivity to MRI scanning in adolescents

Magnetic resonance imaging (MRI) is a procedure that is now widely used to study emotional and cognitive processes in children and adolescents. However, the context within which brain imaging data are collected is a social context that may induce anxiety and stress. Several hormones have been shown to be responsive to environmental stressors. These stress responses may impact ability to successfully complete the procedure or collect imaging data. To investigate these issues, we measured salivary cortisol, dehydroepiandrosterone (DHEA), and testosterone in 160 adolescents during both a simulation (practice) and actual MRI. Hormones were all responsive to the MRI scan, indicating that an MRI scan itself can induce a stress response, with some hormones predicting the likelihood that an adolescent could successfully complete the scan with adequate data. The simulation scan did not hinder hormonal responses to the actual MRI. These data suggest that researchers should consider the effects of heightened hormonal reactivity to the scanning environment; adolescent's reactions to brain imaging may contribute to image data loss and may potentially influence outcome measures.     

Susceptibility to prosocial and antisocial influence in adolescence

IntroductionAdolescents are particularly susceptible to social influence and previous studies have shown that this susceptibility decreases with age. The current study used a cross-sectional experimental paradigm to investigate the effect of age and puberty on susceptibility to both prosocial and antisocial influence.MethodsParticipants (N = 520) aged 11–18 from London and Cambridge (United Kingdom) rated how likely they would be to engage in a prosocial (e.g. “help a classmate with their work”) or antisocial (e.g. “make fun of a classmate”) act. They were then shown the average rating (in fact fictitious) that other adolescents had given to the same question, and were then asked to rate the same behaviour again.ResultsBoth prosocial and antisocial influence decreased linearly with age, with younger adolescents being more socially influenced when other adolescents’ ratings were more prosocial and less antisocial than their own initial rating. Both antisocial and prosocial influence significantly decreased across puberty for boys but not girls (independent of age).ConclusionsThese findings suggest that social influence declines with increasing maturity across adolescence. However, the exact relationship between social influence and maturity is dependent on the nature of the social influence and gender. Understanding when adolescents are most susceptible to different types of social influence, and how this might influence their social behaviour, has important implications for understanding adolescent social development.     

The neural correlates of emotion alignment in social interaction

Talking about emotion and sharing emotional experiences is a key component of human interaction. Specifically, individuals often consider the reactions of other people when evaluating the meaning and impact of an emotional stimulus. It has not yet been investigated, however, how emotional arousal ratings and physiological responses elicited by affective stimuli are influenced by the rating of an interaction partner. In the present study, pairs of participants were asked to rate and communicate the degree of their emotional arousal while viewing affective pictures. Strikingly, participants adjusted their arousal ratings to match up with their interaction partner. In anticipation of the affective picture, the interaction partner’s arousal ratings correlated positively with activity in anterior insula and prefrontal cortex. During picture presentation, social influence was reflected in the ventral striatum, that is, activity in the ventral striatum correlated negatively with the interaction partner’s ratings. Results of the study show that emotional alignment through the influence of another person’s communicated experience has to be considered as a complex phenomenon integrating different components including emotion anticipation and conformity.     

Identity, prosocial behavior, and generative concern in German and Cameroonian Nso adolescents

Little is known about whether ego identity statuses have the same developmental concomitants in different cultural contexts. Thus, 159 German and 158 Cameroonian Nso adolescents aged 15-18 were recruited to test if associations between identity and generativity (i.e. the desire to create a positive legacy) and prosocial behavior (i.e. helpful and supportive behavior), respectively, are comparable. In both cultural samples, only identity achievement was positively linked with generative concern and prosocial tendencies. Integrating these and previous findings on the association between prosocial behavior and generativity, a partial mediation of the relation between identity achievement and generative concern through prosocial tendencies was hypothesized and confirmed for both cultural groups. Thus, there is an equivalent association between identity achievement, prosocial behavior, and generative concern in adolescents with widely different cultural background.     

Behavioral and neural correlates of loss aversion and risk avoidance in adolescents and adults

Individuals are frequently faced with risky decisions involving the potential for both gain and loss. Exploring the role of both potential gains and potential losses in predicting risk taking is critical to understanding how adolescents and adults make the choice to engage in or avoid a real-life risk. This study aimed to examine the impact of potential losses as well as gains on adolescent decisions during risky choice in a laboratory task. Adolescent (n=18) and adult (n=16) participants underwent functional magnetic resonance imaging (fMRI) during a mixed gambles task, and completed questionnaires measuring real-world risk-taking behaviors. While potential loss had a significantly greater effect on choice than potential gain in both adolescents and adults and there were no behavioral group differences on the task, adolescents recruited significantly more frontostriatal circuitry than adults when choosing to reject a gamble. During risk-seeking behavior, adolescent activation in medial prefrontal cortex (mPFC) was negatively correlated with self-reported likelihood of risk taking. During risk-avoidant behavior, mPFC activation of in adults was negatively correlated with self-reported benefits of risk-taking. Taken together, these findings reflect different neural patterns during risk-taking and risk-avoidant behaviors in adolescents and adults.     

Estimating peer effects in sexual behavior among adolescents

In this paper we seek to empirically quantify the role of peer social networks in influencing sexual behavior among adolescents. Using data of a nationally representative sample of adolescents we utilize a multivariate structural model with school-level fixed effects to account for the problems of contextual effects, correlated effects and peer selections to purge the potential biases from the estimates of peer influence. Our peer group measures are drawn not only from the nomination of close friends, but also from classmates. Controlling for parent level characteristics, and other demographic parameters, we find that a 10% increase in the proportion of close friends who initiates sex increases the probability that an individual chooses to initiate sex by 5% and a 10% increase in number of sexual partners among close friends increases an individual's sexual partner by 5%. The influence of classmates however, diminishes in magnitude after accounting for unobserved environmental confounders.     

Neurobiological correlates of social conformity and independence during mental rotation.

BACKGROUND: When individual judgment conflicts with a group, the individual will often conform his judgment to that of the group. Conformity might arise at an executive level of decision making, or it might arise because the social setting alters the individual's perception of the world. METHODS: We used functional magnetic resonance imaging and a task of mental rotation in the context of peer pressure to investigate the neural basis of individualistic and conforming behavior in the face of wrong information. RESULTS: Conformity was associated with functional changes in an occipital-parietal network, especially when the wrong information originated from other people. Independence was associated with increased amygdala and caudate activity, findings consistent with the assumptions of social norm theory about the behavioral saliency of standing alone. CONCLUSIONS: These findings provide the first biological evidence for the involvement of perceptual and emotional processes during social conformity.     

Extrinsic relative to intrinsic goal pursuits and peer dynamics: Selection and influence processes among adolescents

Self-Determination Theory discerns goals and values in terms of whether they are intrinsic or extrinsic in nature. Although research substantiates the importance of goal preferences for a host of outcomes, few studies examined how such preferences develop, and studies that did pay attention to this focused on parental influence processes. The present study focuses on the role of peers. Social network analyses on longitudinal data gathered among senior high-school students (N = 695) confirm that peer similarity in goal pursuit exists, and that, although this similarity partly originates from adolescents selecting friends on the basis of perceived goal pursuit similarity, it also results from peers actively influencing each other. Hence, friends tend to become more alike in terms of goal pursuit over time. Data also suggest that, although changes in goal pursuit at this age can be predicted from peer dynamics, they cannot be attributed to parental goal promotion efforts.     

Links between self-reported media violence exposure and teacher ratings of aggression and prosocial behavior among German adolescents

The relations between adolescents’ habitual usage of media violence and their tendency to engage in aggressive and prosocial behavior in a school setting were examined in a cross-sectional study with 1688 7th and 8th graders in Germany who completed measures of violent media exposure and normative acceptance of aggression. For each participant, ratings of prosocial and aggressive behavior were obtained from their class teacher. Media violence exposure was a unique predictor of teacher-rated aggression even when relevant covariates were considered, and it predicted prosocial behavior over and above gender. Path analyses confirmed a direct positive link from media violence usage to teacher-rated aggression for girls and boys, but no direct negative link to prosocial behavior was found. Indirect pathways were identified to higher aggressive and lower prosocial behavior via the acceptance of aggression as normative. Although there were significant gender differences in media violence exposure, aggression, and prosocial behavior, similar path models were identified for boys and girls.     

Characterizing and decomposing the neural correlates of individual differences in reading ability among adolescents with task-based fMRI

To better characterize the neural correlates of the full spectrum of reading ability, this fMRI study examined how variations in reading ability correlate with task-based brain activity during reading among a large community sample of adolescents (N = 234). In addition, complimentary approaches taking advantage of empirical as well as independent meta-analytic information were employed to isolate neural substrates of domain-general executive processes that are predictive of reading ability. Age-related differences in brain activity were also examined. Better reading was associated with increased activation in left anterior and inferior temporal regions and parts of orbitofrontal cortex, along with reduced activation in the thalamus and left frontal eye field (FEF). Converging evidence suggests that FEF activity corresponds to executive processes during reading. In contrast, activity in temporal regions is likely to reflect cognitive processes specific to reading. Older adolescents also demonstrated increased activation in an orbitofrontal region that overlaps with the aforementioned age-independent, reading-related regions, along with reduced activity in parietal and occipital regions. These results suggest that comparedto poor readers, proficient readers benefit from efficient reading-specific processes and require less executive effort, implemented via the FEF, during a reading comprehension task.     

Neural correlates associated with conformity in adolescent and young adult men

Social influence affects us throughout our lives, shaping our attitudes, behaviors, and preferences. Thus, the current study aimed to examine whether key age groups (adolescence versus young adulthood) were associated with differences in neural correlates associated with processing social feedback and conformity (i.e., conflict detection, positive valuation, and mentalizing) among young men. We recruited 153 participants across 5 studies, who completed a social influence task during an fMRI scan. Overall, participants were more likely to conform by changing their ratings when misaligned with others, and adolescents were more likely to conform when misaligned (compared to aligned) with others compared to young adults. Further, we found that adolescents showed increased activity in mentalizing (TPJ, dmPFC) and positive valuation regions (VS, vmPFC), compared to young adults, in response to misalignment with others. In contrast, young adults showed increased activity in conflict detection regions (AI, dACC) when exposed to feedback that they were misaligned with others and when conforming to that feedback. Overall, our results offer initial evidence that adolescent and young adult men engage different neural processes when they find out they are misaligned with others and when conforming to the recommendations of others, and this difference appears to track with brain responses in conflict detection, mentalizing and value regions.Data statementRaw data and analysis codes are available upon request.     

Variants of uncertainty in decision-making and their neural correlates

When leaving the tidy world of rules and people start judging probabilities on an intuitive basis, it revealed that they have some intuitions to choose from. One could refer to them as a family of subjective probability concepts or following Kahneman and Tversky, as variants of uncertainty. The authors distinguished between external and internal attributions of uncertainty and could show that the perceived reason of uncertainty determines the selected coping strategy. To investigate whether variants of uncertainty can also be distinguished on the cerebral level, two functional magnetic resonance imaging studies were conducted. Participants had to predict events (abstract visual stimuli) under parametrically varying degrees of (un-)certainty. In the first experiment, uncertainty was induced by the manipulation of event probability (externally attributed uncertainty). In the second experiment, uncertainty depended on participants' knowledge of valid rules of event occurrence, as trained before the experimental session (internally attributed uncertainty). As a result, parametric analyses revealed that activation within the posterior fronto-median cortex, particularly within mesial Brodmann area (BA) 8, increased with increasing uncertainty, no matter for which reason uncertainty emerged. Furthermore, it was found that different variants of uncertainty entailing different coping strategies can be dissociated due to additionally activated networks. Concluding, increasing activation within mesial BA 8 reflects that we are uncertain, additional networks what we do to resolve uncertainty in order to achieve future rewards. Hence, the phenomenological distinction between processes related to externally and internally attributed uncertainty is paralleled on the cerebral level.     

Simulating the neural correlates of stuttering

For functional neuroimaging studies of stuttering, two challenges are (1) the elicitation of naturally stuttered versus fluent speech and (2) the separation of activation associated with abnormal motor execution from activation that reflects the cognitive substrates of stuttering. This paper reports on a proof-of-concept study, in which a single-subject approach was applied to address these two issues. A stuttering speaker used his insight into his own stuttering behavior to create a list of stutter-prone words versus a list of “fluent” words. He was then matched to a non-stuttering speaker, who imitated the specific articulatory and orofacial motor pattern of the stuttering speaker. Both study participants performed a functional MRI experiment of single word reading, each being presented with the same lexical items. Results suggest that the generally observed right-hemisphere lateralization appears to reflect a true neural correlate of stuttering. Some of the classically reported activation associated with stuttering appears to be driven more by nonspecific motor patterns than by cognitive substrates of stuttering, while anterior cingulate activation may reflect awareness of (upcoming) dysfluencies. This study shows that it is feasible to match stuttering speakers’ utterances more closely to simulated stutters for the investigation of neural correlates of real stuttering. Significant main effects and contrast effects were obtained for the differences between fluent and stuttered speech, and right-hemisphere lateralization associated with real stuttered speech was shown in a single subject.     

Physiological correlates of self-injurious behavior in captive, socially-reared rhesus monkeys

This study examined the relationship between self-injurious behavior (SIB) in rhesus monkeys and several biological variables, including monoamine metabolites in cerebrospinal fluid (CSF) and circulating levels of ACTH, cortisol, and testosterone. Cisternal CSF and blood plasma samples were obtained from 23 individually housed male rhesus macaques, 14 of which had a veterinary record of self-inflicted wounding. CSF samples were analyzed for 5-hydroxyindole-3-acetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) using isocratic high-performance liquid chromatography with electrochemical detection (HPLC-EC). Plasma samples were analyzed for ACTH, cortisol, and testosterone using commercially available radioimmunoassays (RIAs). Rates of self-directed biting were determined by systematic observation of all monkeys. Monkeys with SIB did not differ from controls in their basal monoamine or gonadal activity. However, the SIB group showed consistently lower mean plasma cortisol levels than the control group. Plasma cortisol was negatively correlated with rates of self-directed biting. These results suggest a persistent dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in monkeys with SIB. It is not yet clear whether this phenomenon of low cortisol represents chronically reduced adrenocortical secretion under basal conditions or a difference in response to the mild stress of capture and chemical restraint. The implications of these findings will be discussed with respect to SIB in humans as well as post-traumatic stress disorder (PTSD), a condition characterized by pituitary-adrenocortical hypoactivity.     

Brief report: Personality correlates of susceptibility to peer influence in adolescence

Adolescents show a heightened susceptibility to peer influence compared to adults. Individual differences in this susceptibility exist, yet there has been little effort to link these with broader personality processes. Reward sensitivity and impulsive behaviour are also heightened in adolescence and could affect the tendency to be influenced by peers. This study examined associations between self-reported resistance to peer influence, facets of reward sensitivity and impulsivity, and subjective social status in a sample of 269 British sixth form students (mean age 16.79). Multiple regression analyses showed that negative and positive urgency were significantly negatively associated with resistance to peer influence. The relationship between negative urgency and resistance was moderated by subjective social status, such that individuals reporting low status showed a stronger negative relationship. Results suggest that a susceptibility to peer influence is linked with a tendency to act impulsively when in heightened emotional states. Adolescents high in negative urgency who feel lower in their social hierarchy may be particularly vulnerable.     

The neural correlates of beauty comparison

Beauty is in the eye of the beholder. How attractive someone is perceived to be depends on the individual or cultural standards to which this person is compared. But although comparisons play a central role in the way people judge the appearance of others, the brain processes underlying attractiveness comparisons remain unknown. In the present experiment, we tested the hypothesis that attractiveness comparisons rely on the same cognitive and neural mechanisms as comparisons of simple nonsocial magnitudes such as size. We recorded brain activity with functional magnetic resonance imaging (fMRI) while participants compared the beauty or height of two women or two dogs. Our data support the hypothesis of a common process underlying these different types of comparisons. First, we demonstrate that the distance effect characteristic of nonsocial comparisons also holds for attractiveness comparisons. Behavioral results indicated, for all our comparisons, longer response times for near than far distances. Second, the neural correlates of these distance effects overlapped in a frontoparietal network known for its involvement in processing simple nonsocial quantities. These results provide evidence for overlapping processes in the comparison of physical attractiveness and nonsocial magnitudes.     

The neural correlates of positive self-evaluation and self-related memory

Humans tend to have a positive self-evaluation (PSE). To what extent positive self-perception is interacting with valenced self-related memories is debated. The underlying neural substrates are not adequately explained yet. To explore the cerebral correlates of PSE and its influence on memory, 24 healthy subjects were asked during fMRI to decide in two conditions whether presented positive and negative personality traits characterized their own selves (self-evaluation) or an intimate other (other-evaluation). A lexical condition served as control task. In a subsequent unannounced recognition task, trait adjectives had to be classified as old or new. Activation during positive self- vs positive other-evaluation was found in the medial ventral and dorsolateral prefrontal gyri, the parahippocampus and the supplementary motor area. Memory increased for positive personality traits and traits that had been referred to oneself or the other. In contrast to adjectives of the other-evaluation or lexical condition, recollection of negative vs positive traits of the self-evaluation condition specifically induced increased activation in the hippocampus and several prefrontal and temporal areas. Our data imply a specific network for PSE (although intimate others are perceived similarly). Moreover, memory for traits contradicting PSE resulted in activation increases indicating greater cognitive effort and emotional involvement.     

Neural correlates of social decision-making in severely antisocial adolescents

Neurobiological and behavioral findings suggest that the development of delinquent behavior is associated with atypical social-affective processing. However, to date, no study has examined neural processes associated with social interactions in severely antisocial adolescents. In this study we investigated the behavioral and neural processes underlying social interactions of juvenile delinquents and a matched control group. Participants played the mini-Ultimatum Game as a responder while in the MRI scanner. Participants rejected unfair offers significantly less when the other player had ‘no alternative’ compared with a ‘fair’ alternative, suggesting that they took the intentions of the other player into account. However, this effect was reduced in the juvenile delinquents. The neuroimaging results revealed that juvenile delinquents showed less activation in the temporal parietal junction (TPJ) and inferior frontal gyrus (IFG). However, the groups showed similar activation levels in the dorsal anterior cingulate cortex (dACC) and the right anterior insula (AI) when norms were violated. These results indicate that juvenile delinquents with severe antisocial behavior process norm violations adequately, but may have difficulties with attending spontaneously to relevant features of the social context during interactions.