Social network position, trust behavior, and neural activity in young adolescents.

Our social interactions take place within numerous social networks, in which our relationships with others define our position within these networks. In this study, we examined how the centrality of positions within social networks was associated with trust behavior and neural activity in 49 adolescents (Mage = 12.8 years, SDage = 0.4 years). The participants played a trust game with a cartoon animation as a partner, which showed adaptive behavior in response to the participant and was generally untrustworthy. Social network positions were obtained in secondary school classrooms where the participants and their classmates reported on who their friends were. Using social network analysis, a score was calculated that indicated the centrality of everyone's position within the friendship network. The results showed that more central social network positions were associated with higher levels of initial trust behavior, although no evidence was found for a relationship between network position and the adaptation of trust behavior. The results of the functional MRI analyses showed that the centrality of the network positions was positively associated with caudate activity when making trust decisions. Furthermore, the adolescents with more central network positions also showed stronger increases of caudate activity when the partner's return was processed compared to the adolescents with less central network positions. The current study provides initial evidence that social network positions in friendship networks relate to socio-cognitive behavior and neural activity in adolescents.

The Effect of Relative Pubertal Maturation and Perceived Popularity on Symptoms of Depression and Social Anxiety in Adolescent Boys and Girls.

Research has shown that adolescents - particularly girls - who mature relatively early often experience more internalizing problems. This effect is thought to be partially driven by psychosocial mechanisms, but previous research based relative pubertal maturation on complete samples or population standards, instead of considering the adolescents' direct peer environment. In the current study the level of adolescents' pubertal development was assessed relative to their classmates in order to examine relative pubertal maturation. The effects of adolescents' relative pubertal status, and their perceived popularity, on symptoms of social anxiety and depression in adolescents were studied. All analyses were also performed for absolute pubertal maturation. Participants were 397 young adolescents (Mage = 13.06, SD = 0.36, 49.9% girls) at timepoint 1, and 307 (Mage = 14.08, SD = 0.36, 50.5% girls) at timepoint 2. A significant positive relationship was found between relative pubertal timing and symptoms of depression for girls but not boys. Social anxiety symptoms were not significantly related to relative pubertal timing in either sex. Relative pubertal maturation had no effect on change in or persistence of depressive and social anxiety symptoms one year later. The effects of the comparison with the immediate peer environment, did not seem to explain more variance in internalizing symptoms than the effects of early maturation.

Developmental Maturation of the Precuneus as a Functional Core of the Default Mode Network.

Efforts to map the functional architecture of the developing human brain have shown that connectivity between and within functional neural networks changes from childhood to adulthood. Although prior work has established that the adult precuneus distinctively modifies its connectivity during task versus rest states [Utevsky, A. V., Smith, D. V., & Huettel, S. A. Precuneus is a functional core of the default-mode network. Journal of Neuroscience, 34, 932-940, 2014], it remains unknown how these connectivity patterns emerge over development. Here, we use fMRI data collected at two longitudinal time points from over 250 participants between the ages of 8 and 26 years engaging in two cognitive tasks and a resting-state scan. By applying independent component analysis to both task and rest data, we identified three canonical networks of interest-the rest-based default mode network and the task-based left and right frontoparietal networks (LFPN and RFPN, respectively)-which we explored for developmental changes using dual regression analyses. We found systematic state-dependent functional connectivity in the precuneus, such that engaging in a task (compared with rest) resulted in greater precuneus-LFPN and precuneus-RFPN connectivity, whereas being at rest (compared with task) resulted in greater precuneus-default mode network connectivity. These cross-sectional results replicated across both tasks and at both developmental time points. Finally, we used longitudinal mixed models to show that the degree to which precuneus distinguishes between task and rest states increases with age, due to age-related increasing segregation between precuneus and LFPN at rest. Our results highlight the distinct role of the precuneus in tracking processing state, in a manner that is both present throughout and strengthened across development.

Developmental patterns of change in the influence of safe and risky peer choices on risky decision-making.

Adolescents take more risks when peers monitor their behavior. However, it is largely unknown how different types of peer influence affect adolescent decision-making. In this study, we investigate how information about previous choices of peers differentially influences decision-making in adolescence and young adulthood. Participants (N = 99, age range 12-22) completed an economic choice task in which choice options were systematically varied on levels of risk and ambiguity. On each trial, participants selected between a safer choice (low variability in outcome) and a riskier choice (high variability in outcome). Participants made choices in three conditions: a solo condition in which they made choices with no additional information, a social condition in which they saw choices of supposed peers, and a computer condition in which they saw choices of a computer. Results showed that participants' choices conform to the choices made by the peers, but not a computer. Furthermore, when peers chose the safe option, late adolescents were especially likely to make a safe choice. Conversely, when the peer made a risky choice, late adolescents were least likely to follow choices made by the peer. We did not find evidence for differential influence of social information on decisions depending on their level of risk and ambiguity. These results show that information about previous decisions of peers are a powerful modifier for behavior and that the effect of peers on adolescents' decisions is less ubiquitous and more specific than previously assumed.

Understanding the Role of Puberty in Structural and Functional Development of the Adolescent Brain.

Over the past two decades, there has been a tremendous increase in our understanding of structural and functional brain development in adolescence. However, understanding the role of puberty in this process has received much less attention. This review examines this relationship by summarizing recent research studies where the role of puberty was investigated in relation to brain structure, connectivity, and task-related functional magnetic resonance imaging (fMRI). The studies together suggest that puberty may contribute to adolescent neural reorganization and maturational advancement, and sex differences also emerge in puberty. The current body of work shows some mixed results regarding impact and exact direction of pubertal influence. We discuss several limitations of current studies and propose future directions on how to move the field forward.

Contributions of Reward Sensitivity to Ventral Striatum Activity Across Adolescence and Early Adulthood.

It was examined how ventral striatum responses to rewards develop across adolescence and early adulthood and how individual differences in state- and trait-level reward sensitivity are related to these changes. Participants (aged 8-29 years) were tested across three waves separated by 2 years (693 functional MRI scans) in an accelerated longitudinal design. The results confirmed an adolescent peak in reward-related ventral striatum, specifically nucleus accumbens, activity. In early to mid-adolescence, increases in reward activation were related to trait-level reward drive. In mid-adolescence to early adulthood decreases in reward activation were related to decreases in state-level hedonic reward pleasure. This study demonstrates that state- and trait-level reward sensitivity account for reward-related ventral striatum activity in different phases of adolescence and early adulthood.

Development of Multifaceted Risk Taking and the Relations to Sex Steroid Hormones: A Longitudinal Study.

Risk taking is a multidimensional construct. It is currently unclear which aspects of risk-taking change most during adolescence and if/how sex hormones contribute to risk-taking tendencies. This study applied a longitudinal design with three time-points, separated by 2 years, in participants aged 8-29 years (670 observations). The Balloon Analogue Risk Task, a delay discounting task, and various self-report questionnaires were administered, to measure aspects of risk taking. Longitudinal analyses demonstrated mostly nonlinear age-related patterns in risk-taking behavior and approach-related personality characteristics (peaking in late adolescence). Increased testosterone and estradiol were found to increase risk-taking behavior and impulsive personality, but decrease avoidance-like personality. This study demonstrates that risk taking is most pronounced in mid-to-late adolescence and suggests that sex hormones accelerate this maturational process.

Brain activation upon ideal-body media exposure and peer feedback in late adolescent girls.

Media's prevailing thin-body ideal plays a vital role in adolescent girls' body image development, but the co-occurring impact of peer feedback is understudied. The present study used functional magnetic resonance imaging (fMRI) to test media imagery and peer feedback combinations on neural activity related to thin-body ideals. Twenty-four healthy female late adolescents rated precategorized body sizes of bikini models (too thin or normal), directly followed by ostensible peer feedback (too thin or normal). Consistent with prior studies on social feedback processing, results showed increased brain activity in the dorsal medial prefrontal cortex (dmPFC)/anterior cingulate cortex (ACC) and bilateral insula in incongruent situations: when participants rated media models' body size as normal while peer feedback indicated the models as too thin (or vice versa). This effect was stronger for girls with lower self-esteem. A subsequent behavioral study (N = 34 female late adolescents, separate sample) demonstrated that participants changed behavior in the direction of the peer feedback: precategorized normal sized models were rated as too thin more often after receiving too thin peer feedback. This suggests that the neural responses upon peer feedback may influence subsequent choice. Our results show that media-by-peer interactions have pronounced effects on girls' body ideals.

Amygdala-orbitofrontal connectivity predicts alcohol use two years later: a longitudinal neuroimaging study on alcohol use in adolescence.

This study tested the relation between cortical-subcortical functional connectivity and alcohol consumption in adolescents using an accelerated longitudinal design, as well as normative developmental patterns for these measures. Participants between ages 8 and 27 completed resting-state neuroimaging scans at two time points separated by two years (N = 274 at T1, N = 231 at T2). In addition, participants between ages 12 and 27 reported on recent and lifetime alcohol use (N = 193 at T1, N = 244 at T2). Resting-state connectivity analyses focused on amygdala-orbitofrontal connectivity given prior research linking reduced coupling between these regions to alcohol use. Mixed model analyses revealed that age had a cubic relationship with alcohol use, with little to no use in childhood, steep increases in adolescence and leveling off in adulthood. No age effects were found for amygdala-OFC connectivity. Prediction analyses showed that left amygdala-orbitofrontal connectivity at the first time point predicted recent and lifetime alcohol use two years later. There was no evidence for the reversed relation, suggesting that brain connectivity measures precede explorative risk-taking behavior in adolescence, possibly because decreased subcortical-frontal connectivity biases towards more explorative or risky behavior.

Longitudinal Changes in Social Brain Development: Processing Outcomes for Friend and Self.

Adolescence is an important time for social development during which friendships become more intimate and complex. In this functional magnetic resonance imaging (fMRI) study we tested how outcomes for friends are processed on the neural level across adolescence. Participants between 8 and 27 years of age were tested twice with a 2-year difference between the first (N = 299) and second (N = 254) time points. Participants performed a task in which they could win and lose money for themselves and their best friend. Mixed linear models revealed a linear decrease in activity in social brain regions for friend > self over development. These results confirm changes in the social brain network across adolescent development, we further show that individual differences are related to these neural changes.

Longitudinal changes in adolescent risk-taking: a comprehensive study of neural responses to rewards, pubertal development, and risk-taking behavior.

Prior studies have highlighted adolescence as a period of increased risk-taking, which is postulated to result from an overactive reward system in the brain. Longitudinal studies are pivotal for testing these brain-behavior relations because individual slopes are more sensitive for detecting change. The aim of the current study was twofold: (1) to test patterns of age-related change (i.e., linear, quadratic, and cubic) in activity in the nucleus accumbens, a key reward region in the brain, in relation to change in puberty (self-report and testosterone levels), laboratory risk-taking and self-reported risk-taking tendency; and (2) to test whether individual differences in pubertal development and risk-taking behavior were contributors to longitudinal change in nucleus accumbens activity. We included 299 human participants at the first time point and 254 participants at the second time point, ranging between ages 8-27 years, time points were separated by a 2 year interval. Neural responses to rewards, pubertal development (self-report and testosterone levels), laboratory risk-taking (balloon analog risk task; BART), and self-reported risk-taking tendency (Behavior Inhibition System/Behavior Activation System questionnaire) were collected at both time points. The longitudinal analyses confirmed the quadratic age pattern for nucleus accumbens activity to rewards (peaking in adolescence), and the same quadratic pattern was found for laboratory risk-taking (BART). Nucleus accumbens activity change was further related to change in testosterone and self-reported reward-sensitivity (BAS Drive). Thus, this longitudinal analysis provides new insight in risk-taking and reward sensitivity in adolescence: (1) confirming an adolescent peak in nucleus accumbens activity, and (2) underlining a critical role for pubertal hormones and individual differences in risk-taking tendency.

The neural coding of feedback learning across child and adolescent development.

The ability to learn from environmental cues is an important contributor to successful performance in a variety of settings, including school. Despite the progress in unraveling the neural correlates of cognitive control in childhood and adolescence, relatively little is known about how these brain regions contribute to learning. In this study, 268 participants aged 8-25 years performed a rule-learning task with performance feedback in a 3T MRI scanner. We examined the development of the frontoparietal network during feedback learning by exploring contributions of age and pubertal development. The pFC showed more activation following negative compared with positive feedback with increasing age. In contrast, our data suggested that the parietal cortex demonstrated a shift from sensitivity to positive feedback in young children to negative feedback in adolescents and adults. These findings were interpreted in terms of separable contributions of the frontoparietal network in childhood to more integrated functions in adulthood. Puberty (testosterone, estradiol, and self-report) did not explain additional variance in neural activation patterns above age, suggesting that development of the frontoparietal network occurs relatively independently from hormonal development. This study presents novel insights into the development of learning, moving beyond a simple frontoparietal immaturity hypothesis.

Gambling for self, friends, and antagonists: differential contributions of affective and social brain regions on adolescent reward processing.

Adolescence is a time of increasing emotional arousal, sensation-seeking and risk-taking, especially in the context of peers. Recent neuroscientific studies have pinpointed to the role of the ventral striatum as a brain region which is particularly sensitive to reward, and to 'social brain' regions, such as the medial prefrontal cortex (mPFC), the precuneus, and the temporal parietal junction, as being particularly responsive to social contexts. However, no study to date has examined adolescents' sensitivity to reward across different social contexts. In this study we examined 249 participants between the ages 8 and 25, on a monetary reward-processing task. Participants could win or lose money for themselves, their best friend and a disliked peer. Winning for self resulted in a mid- to late adolescent specific peak in neural activation in the ventral striatum, whereas winning for a disliked peer resulted in a mid- to late adolescent specific peak in the mPFC. Our findings reveal that ventral striatum and mPFC hypersensitivity in adolescence is dependent on social context. Taken together, these results suggest that increased risk-taking and sensation seeking observed in adolescence might not be purely related to hyperactivity of the ventral striatum, but that these behaviors are probably strongly related to the social context in which they occur.

Delay discounting and frontostriatal fiber tracts: a combined DTI and MTR study on impulsive choices in healthy young adults.

Delay discounting, a measure of impulsive choice, has been associated with decreased control of the prefrontal cortex over striatum responses. The anatomical connectivity between both brain regions in delaying gratification remains unknown. Here, we investigate whether the quality of frontostriatal (FS) white matter tracts can predict individual differences in delay-discounting behavior. We use tract-based diffusion tensor imaging and magnetization transfer imaging to measure the microstructural properties of FS fiber tracts in 40 healthy young adults (from 18 to 25 years). We additionally explored whether internal sex hormone levels affect the integrity of FS tracts, based on the hypothesis that sex hormones modulate axonal density within prefrontal dopaminergic circuits. We calculated fractional anisotropy (FA), mean diffusivity (MD), longitudinal diffusivity, radial diffusivity (RD), and magnetization transfer ratio (MTR), a putative measure of myelination, for the FS tract. Results showed that lower integrity within the FS tract (higher MD and RD and lower FA), predicts faster discounting in both sexes. MTR was unrelated to delay-discounting performance. In addition, testosterone levels in males were associated with a lower integrity (higher RD) within the FS tract. Our study provides support for the hypothesis that enhanced structural integrity of white matter fiber bundles between prefrontal and striatal brain areas is associated with better impulse control.

Growing Up Together in Society (GUTS): A team science effort to predict societal trajectories in adolescence and young adulthood.

Our society faces a great diversity of opportunities for youth. The 10-year Growing Up Together in Society (GUTS) program has the long-term goal to understand which combination of measures best predict societal trajectories, such as school success, mental health, well-being, and developing a sense of belonging in society. Our leading hypothesis is that self-regulation is key to how adolescents successfully navigate the demands of contemporary society. We aim to test these questions using socio-economic, questionnaire (including experience sampling methods), behavioral, brain (fMRI, sMRI, EEG), hormonal, and genetic measures in four large cohorts including adolescents and young adults. Two cohorts are designed as test and replication cohorts to test the developmental trajectory of self-regulation, including adolescents of different socioeconomic status thereby bridging individual, family, and societal perspectives. The third cohort consists of an entire social network to examine how neural and self-regulatory development influences and is influenced by whom adolescents and young adults choose to interact with. The fourth cohort includes youth with early signs of antisocial and delinquent behavior to understand patterns of societal development in individuals at the extreme ends of self-regulation and societal participation, and examines pathways into and out of delinquency. We will complement the newly collected cohorts with data from existing large-scale population-based and case-control cohorts. The study is embedded in a transdisciplinary approach that engages stakeholders throughout the design stage, with a strong focus on citizen science and youth participation in study design, data collection, and interpretation of results, to ensure optimal translation to youth in society.

Pubertal maturation and sex steroids are related to alcohol use in adolescents.

Adolescents often show risk-taking behavior, including experimentation with alcohol. Previous studies have shown that advanced pubertal maturation is related to increased alcohol use in adolescents, even when controlling for age. Little is known about the underlying mechanisms of this relation between pubertal maturation and alcohol use. The goal of the present study was twofold. In Experiment 1, we investigated whether advanced pubertal maturation is associated with higher levels of alcohol use, when controlling for age. To this end, questionnaires on pubertal development and alcohol use were administered to a large sample of 797 Dutch adolescents (405 boys) aged 11-16 years. In Experiment 2, we explored whether sex steroids contribute to this relation between pubertal maturation and alcohol use by examining the association between salivary sex steroid levels and alcohol use in 168 adolescents (86 boys). It was found that, when controlling for age, advanced pubertal maturation is related to increased alcohol use in adolescent boys and girls. Controlling for age, higher testosterone and estradiol levels correlated with the onset of alcohol use in boys. In addition, higher estradiol levels were associated with a larger quantity of alcohol use in boys. Correlations between sex steroids and alcohol use were not significant in girls. These findings show that advanced pubertal maturation is related to advanced alcohol use, and that higher sex steroid levels could be one of the underlying mechanisms of this relation in boys. Sex steroids might promote alcohol use by stimulating brain regions implicated in reward processing.

Adolescent development: From neurobiology to psychopathology.

Adolescence is a time of major psychological development in the cognitive, affective, and social domains. Development in these domains can also show interactions with each other. One way in which these interactions between these domains become apparent is in the form of risk-taking behavior in adolescence. Compared to children and adults, adolescents show increased risky decision-making. An example of risk-taking behavior is substance use, including smoking and the use of e-cigarettes (Huizink). A leading explanation for risk-taking behavior has been an increase in reward sensitivity in adolescence. However, adolescents also show differential processing of risk compared to children and adults. A focus on risk processing could broaden the perspective on adolescent risk-taking behavior (van Duijvenvoorde).

Information about others' choices selectively alters risk tolerance and medial prefrontal cortex activation across adolescence and young adulthood.

Adolescence is associated with major changes in the cognitive, emotional and social domains. One domain in which these processes intersect is decision-making. Previous research has shown that individuals' attitudes towards risk and ambiguity shape their decision-making, and information about others' choices can influence individuals' decisions. However, it is currently unknown how information about others' choices influences risk and ambiguity attitudes separately, and the degree to which others' choices shape decision-making differentially across development from adolescence to young adulthood. The current study used a computational modeling framework to test how information about others' choices influences these attitudes. Participants, aged 14-22 years, made a series of risky and ambiguous choices while undergoing fMRI scanning. On some trials, they viewed risky or safe choices of others. Results showed that participants aligned their choices toward the choice preferences of others. Moreover, the tendency to align choices was expressed in changes in risk attitude, but not ambiguity attitude. The change in risk attitude was positively related to neural activation in the medial prefrontal cortex. Results did not show age related differences in behavior and corresponding neural activation, indicating that the manner in which adolescents are influenced by peers is not ubiquitous but rather, is highly context-dependent.

Friendship stability in adolescence is associated with ventral striatum responses to vicarious rewards.

An important task for adolescents is to form and maintain friendships. In this three-wave biannual study, we used a longitudinal neuroscience perspective to examine the dynamics of friendship stability. Relative to childhood and adulthood, adolescence is marked by elevated ventral striatum activity when gaining self-serving rewards. Using a sample of participants between the ages of eight and twenty-eight, we tested age-related changes in ventral striatum response to gaining for stable (n = 48) versus unstable best friends (n = 75) (and self). In participants with stable friendships, we observed a quadratic developmental trajectory of ventral striatum responses to winning versus losing rewards for friends, whereas participants with unstable best friends showed no age-related changes. Ventral striatum activity in response to winning versus losing for friends further varied with friendship closeness for participants with unstable friendships. We suggest that these findings may reflect changing social motivations related to formation and maintenance of friendships across adolescence.

Majority and popularity effects on norm formation in adolescence.

Personal norms consist of individuals' attitudes about the appropriateness of behaviour. These norms guide adolescents' behaviour in countless domains that are fundamental for their social functioning and well-being. Peers are known to have a marked influence on adolescent risk-taking and prosocial behaviour, but little is known about how peers shape personal norms underlying those behaviours. Here we show that adolescents' personal norms are decisively moulded by the norms of the majority and popular peers in their social network. Our experiment indicates that observing peer norms substantially impacts adolescents' normative evaluation of risk-taking and prosocial behaviours. The majority norm had a stronger impact than the norm of a single popular peer, and norm adjustments were largest when adolescents observed strong disapproval of risk-taking or strong approval of prosocial behaviour. Our study suggests that learning about peer norms likely promotes adolescents to hold views and values supporting socially desirable behaviour.