Morphological properties of the action-observation cortical network in adolescents with low and high resistance to peer influence

YouTube vloggers set the stage: How public (non)compliance with COVID-19 regulations affects adolescents

INTRODUCTION

YouTube vloggers may be important socialization figures, yet their influence on adolescents' health-related behaviors and cognitions is largely untested. In this two-study mixed-method project, we first assessed the extent of (non)compliance to COVID-19 regulations by vloggers on YouTube and how viewers reacted to this. Second, we experimentally assessed the effects of vlogger behavior paired with viewer evaluations on adolescents' COVID-19-related attitudes, intentions, and behavior.

METHODS

For Study 1, we coded 240 vlogs of eight popular Dutch vloggers on YouTube recorded in the period of February 2020-March 2021. For our 2 × 2 between-subjects experiment in Study 2, Dutch adolescents (N = 285, Mage = 12.99, SD = 1.02, 41.8% girls) were randomly assigned to conditions in which they saw vlogs showing either compliance or noncompliance to COVID-19 regulations, and to conditions in which they saw either supportive or dismissive comments under these vlogs.

RESULTS

Study 1: Vloggers' noncompliance with COVID-19 regulations was not uncommon and received relatively more viewer support than compliance, suggesting that portrayed noncompliance may be potentially influential. Study 2: Adolescents were more worried about COVID-19 after they watched a compliant (vs. noncompliant) vlogger. Also, vlogger noncompliance decreased adolescents' perceived importance of COVID-19 regulations and rule-setting for adolescents who identified strongly with the vloggers they watched.

CONCLUSIONS

Vloggers' (non)compliance affects adolescents' COVID-19-related worrying, and attitudes and behavior of adolescents who identify with vloggers strongly. This seems concerning given the sometimes harmful and risky behaviors vloggers portray online but could potentially also be employed to encourage healthy behaviors.

Adolescent exposure to sucrose increases cocaine-mediated behaviours in adulthood via Smad3

Adolescence, a critical period of developmental period, is marked by neurobiological changes influenced by environmental factors. Here, we show how exposure to sucrose, which is ubiquitously available in modern diets, results in changes in behavioural response to cocaine as an adult. Rats were given daily access to either 10% sucrose or water during the adolescent period (PND28-42). Following this period, rats are left undisturbed until they reach adulthood. In adulthood, rats were tested for (i) acquisition of a low dose of cocaine, (ii) progressive ratio (PR) test, and (iii) resistance to punished cocaine taking. Sucrose exposure resulted in significant alterations in all behavioural measures. To determine the neurobiological mechanisms leading to such behavioural adaptations, we find that adolescent sucrose exposure results in an upregulation of the transcription factor Smad3 in the nucleus accumbens (NAc) when compared with water-exposed controls. Transiently blocking the active form of this transcription factor (HSV-dnSmad3) during adolescence mitigated the enhanced cocaine vulnerability-like behaviours observed in adulthood. These findings suggest that prior exposure to sucrose during adolescence can heighten the reinforcing effects of cocaine. Furthermore, they identify the TGF-beta pathway and Smad3 as playing a key role in mediating enduring and long-lasting adaptations that contribute to sucrose-induced susceptibility to cocaine. Taken together, these results have important implications for development and suggest that adolescent sucrose exposure may persistently enhance the susceptibility to substance abuse.

Risk-Taking Behavior Among Male Adolescents: The Role of Observer Presence and Individual Self-Control

A number of studies have focused on the same-sex peer effect on and the developmental difference in adolescent risk-taking in terms of the dual systems model. Little research, however, addresses the effects of different observers, the role of different levels of individual self-control, and their interactions. To fill this gap, the present study examined the main and interactive effects of observer presence and individual self-control on male adolescents' risk-taking behavior with an experimental design. A total of 261 male adolescents (M_age = 15.79 ± 0.79, range = 14-18) completed an adapted Stoplight Task, which measures risk-taking behavior, in the presence of an observer, either peer or adult, either male or female. The results indicated that a same-sex peer's presence and low self-control were both risk factors of male adolescents' risk-taking, but did only low self-control male adolescents take serious risks when in the presence of a same-sex peer whereas those with high self-control consistently had low levels of risk-taking under any condition. An opposite-sex observer, particularly an opposite-sex adult's presence, played a similar protective role for male adolescents with low self-control. The findings suggest that a high level of self-control closely related to the cognitive control system may significantly buffer the negative effect of an adverse social stimulus which activates the social-emotional system on male adolescents' risk-taking; the findings also reveal that an opposite-sex adult's presence may contribute to a decrease in male adolescents' risk-taking by improving their cognitive control system.

Prenatal stress and its association with amygdala-related structural covariance patterns in youth

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Prenatal exposure to stress predicts amygdala degree centrality in young adulthood.

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High (vs. low) stress group showed lower structural covariance degree of amygdala.

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These effects were particularly significant in men.

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Global network parameters did not drive these effects.

Background

Prenatal stress influences brain development and mood disorder vulnerability. Brain structural covariance network (SCN) properties based on inter-regional volumetric correlations may reflect developmentally-mediated shared plasticity among regions. Childhood trauma is associated with amygdala-centric SCN reorganization patterns, however, the impact of prenatal stress on SCN properties remains unknown.

Methods

The study included participants from the European Longitudinal Study of Pregnancy and Childhood (ELSPAC) with archival prenatal stress data and structural MRI acquired in young adulthood (age 23–24). SCNs were constructed based on Freesurfer-extracted volumes of 7 subcortical and 34 cortical regions. We compared amygdala degree centrality, a measure of hubness, between those exposed to high vs. low (median split) prenatal stress, defined by maternal reports of stressful life events during the first (n = 93, 57% female) and second (n = 125, 54% female) half of pregnancy. Group differences were tested across network density thresholds (5–40%) using 10,000 permutations, with sex and intracranial volume as covariates, followed by sex-specific analyses. Finally, we sought to replicate our results in an independent all-male sample (n = 450, age 18–20) from the Avon Longitudinal Study of Parents and Children (ALSPAC).

Results

The high-stress during the first half of pregnancy ELSPAC group showed lower amygdala degree particularly in men, who demonstrated this difference at 10 consecutive thresholds, with no significant differences in global network properties. At the lowest significant density threshold, amygdala volume was positively correlated with hippocampus, putamen, rostral anterior and posterior cingulate, transverse temporal, and pericalcarine cortex in the low-stress (p(FDR) < 0.027), but not the high-stress (p(FDR) > 0.882) group. Although amygdala degree was nominally lower across thresholds in the high-stress ALSPAC group, these results were not significant.

Conclusion

Unlike childhood trauma, prenatal stress may shift SCN towards a less amygdala-centric SCN pattern, particularly in men. These findings did not replicate in an all-male ALSPAC sample, possibly due to the sample’s younger age and lower prenatal stress exposure.

Brain microstructural changes in mice persist in adulthood and are modulated by the palmitoyl acyltransferase ZDHHC7

For a long time, mice have been classified as adults with completely mature brains at 8 weeks of age, but recent research suggests that developmental brain changes occur for up to 6 months. In particular, adolescence coincides with dramatic changes of neuronal structure and function in the brain that influence the connectivity between areas like hippocampus and medial prefrontal cortex (mPFC). Neuronal development and plasticity are regulated in part by the palmitoyl acyltransferase ZDHHC7, which modulates structural connectivity between hippocampus and mPFC. The aim of the current study was to investigate whether developmental changes take place in hippocampus and mPFC microstructure even after 8 weeks of age and whether deficiency of ZDHHC7 impacts such age-dependent alterations. Altogether, 46 mice at 11, 14 or 17 weeks of age with a genetic Zdhhc7 knockout (KO) or wild type (WT) were analysed with neuroimaging and diffusion tensor-based fibre tractography. The hippocampus and mPFC regions were compared regarding fibre metrics, supplemented by volumetric and immunohistological analyses of the hippocampus. In WT animals, we identified age-dependent changes in hippocampal fibre lengths that followed a U-shaped pattern, whereas in mPFC, changes were linear. In Zdhhc7-deficient animals, the fibre statistics were reduced in both regions, whereas the hippocampus volume and the intensities of myelin and neurofilament were higher in 11-week-old KO mice compared to WTs. Our results confirmed ongoing changes of microstructure in mice up to 17 weeks old and demonstrate that deleting the Zdhhc7 gene impairs fibre development, suggesting that palmitoylation is important in this process.

Expression of Oligodendrocyte and Oligoprogenitor Cell Proteins in Frontal Cortical White and Gray Matter: Impact of Adolescent Development and Ethanol Exposure

Adolescent development of prefrontal cortex (PFC) parallels maturation of executive functions as well as increasing white matter and myelination. Studies using MRI and other methods find that PFC white matter increases across adolescence into adulthood in both humans and rodents. Adolescent binge drinking is common and has been found to alter adult behaviors and PFC functions. This study examines development of oligoprogenitor (OPC) and oligodendrocytes (OLs) in Wistar rats from adolescence to adulthood within PFC white matter, corpus callosum forceps minor (fmi), PFC gray matter, and the neurogenic subventricular zone (SVZ) using immunohistochemistry for marker proteins. In addition, the effects of adolescent intermittent ethanol exposure [AIE; 5.0 g/kg/day, intragastric, 2 days on/2 days off on postnatal day (P)25-54], which is a weekend binge drinking model, were determined. OPC markers NG2+, PDGFRα+ and Olig2+IHC were differentially impacted by both age and PFC region. In both fmi and SVZ, NG2+IHC cells declined from adolescence to adulthood with AIE increasing adult NG2+IHC cells and their association with microglial marker Iba1. PFC gray matter decline in NG2+IHC in adulthood was not altered by AIE. Both adult maturation and AIE impacted OL expression of PLP+, MBP+, MAG+, MOG+, CNPase+, Olig1+, and Olig2+IHC in all three PFC regions, but in region- and marker-specific patterns. These findings are consistent with PFC region-specific changes in OPC and OL markers from adolescence to adulthood as well as following AIE that could contribute to lasting changes in PFC function.

Molecular and neuronal mechanisms underlying the effects of adolescent nicotine exposure on anxiety and mood disorders

Tobacco addiction is highly co-morbid with a variety of mental health conditions, including schizophrenia, mood and anxiety disorders. Nicotine, the primary psychoactive compound in tobacco-related products is known to functionally modulate brain circuits that are disturbed in these disorders. Nicotine can potently regulate the transmission of various neurochemicals, including dopamine (DA), γ-amino-butyric acid (GABA) and glutamate, within various mesocorticolimbic structures, such as the ventral tegmental area (VTA), nucleus accumbens (NAc) and prefrontal cortex (PFC), all of which show pathologies in these disorders. Many neuropsychiatric diseases have etiological origins during neurodevelopment, typically occurring during vulnerable periods of adolescent or pre-natal brain development. During these neurodevelopmental periods, exposure to extrinsic drug insults can induce enduring and long-term pathophysiological sequelae that ultimately increase the risk of developing chronic mental health disorders in later life. These vulnerability factors are of growing concern given rising rates of adolescent nicotine exposure via traditional tobacco use and the increasing use of alternative nicotine delivery formats such as vaping and e-cigarettes. A large body of clinical and pre-clinical evidence points to an important role for adolescent exposure to nicotine and increased vulnerability to developing mood and anxiety disorders in later life. This review will examine current clinical and pre-clinical evidence that pinpoints specific mechanisms within the mesocorticolimbic circuitry and molecular biomarkers linked to the association between adolescent nicotine exposure and increased risk of developing mood and anxiety-related disorders. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Developmental trajectory of interpersonal motor alignment: Positive social effects and link to social cognition

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Interpersonal motor alignment (IMA) has positive effects on healthy social life.

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IMA - mimicry, synchrony, automatic imitation - is studied throughout development.

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It relies on motor resonance brain mechanisms identified throughout development.

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It is modulated by contextual and personal factors.

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IMA is underinvestigated in adolescence, yet it may aid to enhance resilience.

Interpersonal motor alignment is a ubiquitous behavior in daily social life. It is a building block for higher social cognition, including empathy and mentalizing and promotes positive social effects. It can be observed as mimicry, synchrony and automatic imitation, to name a few. These phenomena rely on motor resonance processes, i.e., a direct link between the perception of an action and its execution. While a considerable literature debates its underlying mechanisms and measurement methods, the question of how motor alignment comes about and changes in ontogeny all the way until adulthood, is rarely discussed specifically. In this review we will focus on the link between interpersonal motor alignment, positive social effects and social cognition in infants, children, and adolescents, demonstrating that this link is present early on in development. Yet, in reviewing the existing literature pertaining to social psychology and developmental social cognitive neuroscience, we identify a knowledge gap regarding the healthy developmental changes in interpersonal motor alignment especially in adolescence.

Resilience in adolescence: Prospective Self moderates the association of early life adversity with externalizing problems

INTRODUCTION

Early life adversity (ELA) can result in negative behavioral outcomes, including internalizing and externalizing problems. Evidence suggests that adolescence is a critical developmental period for processing ELA. Identity formation, which is crucial to this developmental period, may moderate the effect between ELA and these problems. One potential moderating variable associated with identity formation is the latent construct Prospective Self, comprised of future-oriented attitudes and behaviors.

METHODS

Participants are from the first wave of an ongoing longitudinal study designed to characterize behavioral and cognitive correlates of risk behavior trajectories. A community sample of 10th and 12th grade adolescents (N = 2017, 55% female) were recruited from nine public school districts across eight Southeastern Michigan counties in the United States. Data were collected in schools during school hours or after school via self-report, computer-administered surveys. Structural equation modeling was utilized to assess Prospective Self as a latent construct and to evaluate the relationship between ELA, internalizing and externalizing problems, and Prospective Self.

RESULTS

Preliminary findings indicated a satisfactory fit for the construct Prospective Self. The predicted negative associations between Prospective Self and internalizing and externalizing problems were found and evidence of moderation was observed for externalizing problems, such that the effects of ELA (i.e., childhood maltreatment) on externalizing problems were lower for individuals with higher levels of Prospective Self.

CONCLUSIONS

These results indicate that Prospective Self may play a role in supporting resilience against externalizing problems associated with ELA among adolescents.

Formal Modeling of the Resistance to Peer Influence Questionnaire: A Comparison of Adolescent Boys and Girls With and Without Mild-to-Borderline Intellectual Disability

Items of the Resistance to Peer Influence Questionnaire (RPIQ) have a tree-based structure. On each item, individuals first choose whether a less versus more peer-resistant group best describes them; they then indicate whether it is "Really true" versus "Sort of true" that they belong to the chosen group. Using tree-based item response theory, we show that RPIQ items tap three dimensions: A Resistance to Peer Influence (RPI) dimension and two Response Polarization dimensions. We then reveal subgroup differences on these dimensions. That is, adolescents with mild-to-borderline intellectual disability, compared with typically developing adolescents, are less RPI and more polarized in their responses. Also, girls, compared with boys, are more RPI, and, when high RPI, more polarized in their responses. Together, these results indicate that a tree-based modeling approach yields a more sensitive measure of individuals' RPI as well as their tendency to respond more or less extremely.

Hunting for What Works: Adolescents in Addiction Treatment

Although adolescents are developmentally distinct from adults, they often receive addiction treatment based on adult models. This is problematic because adolescents face significantly different conditions in addiction treatment, including distinct basic biological and neurodevelopmental stages, unique sociodevelopmental concerns, distinctive addiction trajectories, and, in turn, disparate treatment goals and outcomes. In sum, it can be difficult for even savvy clinicians to know how to approach addiction treatment with this important age group. In an effort to help clinicians and researchers consider substance use via a neurodevelopmental lens, we approached this review with 4 goals: (i) characterize the prevalence, and related health and safety implications of substance use within this age group; (ii) identify the nature of the adolescent brain, including characteristic features of this phase of neurodevelopment relevant to adolescent substance use treatment; (iii) provide an overview of current adolescent addiction interventions and avenues to improve clinical treatment and clinical research efforts for adolescents; and (iv) examine the intersection between the nature of the developing brain and adolescent substance use, and utilize that information to inform alternative routes and directions for substance use treatment in this critical age group. This review concludes by offering a novel neurodevelopmental model and framework to examine substance use interventions, along with a series of recommendations to optimize adolescent substance use treatment and clinical research.

Adolescent psychosocial stress enhances sensitization to cocaine exposure in genetically vulnerable mice

Development of drug addictive behaviors is modulated by both genetic and environmental risk factors. However, the molecular mechanisms remain unknown. To address the role of adolescent stress in the development of drug addiction, we combined a transgenic mouse model in which a putative dominant-negative form of DISC1 under expressional control of the prion protein promoter is used as a genetic risk factor and adolescent social isolation stress as a gene-environmental interaction (GXE). Repeated cocaine exposure induced greater locomotion in the GXE group than in the other groups. In a conditioned place preference (CPP) test, GXE mice exhibited a significant place preference to the cocaine-conditioned area compared with the other groups. In the nucleus accumbens (NAc) of GXE mice, we found increased enzyme activity of phosphodiesterase-4 (PDE4), predominantly located in NAc D2-receptor-expressing neurons, and enhanced effects of the PDE4 inhibitor rolipram, but not the D1 agonist SKF81297, on the phosphorylation of DARPP-32 and GluA1 at PKA sites. Rolipram injection before cocaine exposure completely inhibited cocaine-induced hyperlocomotion and CPP in the GXE group. These results indicate that GXE enhances sensitivity to repeated cocaine exposure via an increase in PDE4 activity in NAc D2-recptor-expressing neurons, leading to the development of cocaine addictive behaviors.

Brain Networks Reorganization During Maturation and Healthy Aging-Emphases for Resilience

Maturation and aging are important life periods that are linked to drastic brain reorganization processes which are essential for mental health. However, the development of generalized theories for delimiting physiological and pathological brain remodeling through life periods linked to healthy states and resilience on one side or mental dysfunction on the other remains a challenge. Furthermore, important processes of preservation and compensation of brain function occur continuously in the cerebral brain networks and drive physiological responses to life events. Here, we review research on brain reorganization processes across the lifespan, demonstrating brain circuits remodeling at the structural and functional level that support mental health and are parallelized by physiological trajectories during maturation and healthy aging. We show evidence that aberrations leading to mental disorders result from the specific alterations of cerebral networks and their pathological dynamics leading to distinct excitability patterns. We discuss how these series of large-scale responses of brain circuits can be viewed as protective or malfunctioning mechanisms for the maintenance of mental health and resilience.

Comparison of the adolescent and adult mouse prefrontal cortex proteome

Adolescence is a developmental period characterized by unique behavioral phenotypes (increased novelty seeking, risk taking, sociability and impulsivity) and increased risk for destructive behaviors, impaired decision making and psychiatric illness. Adaptive and maladaptive adolescent traits have been associated with development of the medial prefrontal cortex (mPFC), a brain region that mediates regulatory control of behavior. However, the molecular changes that underlie brain development and behavioral vulnerability have not been fully characterized. Using high-throughput 2D DIGE spot profiling with identification by MALDI-TOF mass spectrometry, we identified 62 spots in the PFC that exhibited age-dependent differences in expression. Identified proteins were associated with diverse cellular functions, including intracellular signaling, synaptic plasticity, cellular organization and metabolism. Separate Western blot analyses confirmed age-related changes in DPYSL2, DNM1, STXBP1 and CFL1 in the mPFC and expanded these findings to the dorsal striatum, nucleus accumbens, motor cortex, amygdala and ventral tegmental area. Ingenuity Pathway Analysis (IPA) identified functional interaction networks enriched with proteins identified in the proteomics screen, linking age-related alterations in protein expression to cellular assembly and development, cell signaling and behavior, and psychiatric illness. These results provide insight into potential molecular components of adolescent cortical development, implicating structural processes that begin during embryonic development as well as plastic adaptations in signaling that may work in concert to bring the cortex, and other brain regions, into maturity.

Abnormal development of sensory-motor, visual temporal and parahippocampal cortex in children with learning disabilities and borderline intellectual functioning

Borderline intellectual functioning (BIF) is a condition characterized by an intelligence quotient (IQ) between 70 and 85. BIF children present with cognitive, motor, social, and adaptive limitations that result in learning disabilities and are more likely to develop psychiatric disorders later in life. The aim of this study was to investigate brain morphometry and its relation to IQ level in BIF children. Thirteen children with BIF and 14 age- and sex-matched typically developing (TD) children were enrolled. All children underwent a full IQ assessment (WISC-III scale) and a magnetic resonance (MR) examination including conventional sequences to assess brain structural abnormalities and high resolution 3D images for voxel-based morphometry analysis. To investigate to what extent the group influenced gray matter (GM) volumes, both univariate and multivariate generalized linear model analysis of variance were used, and the varimax factor analysis was used to explore variable correlations and clusters among subjects. Results showed that BIF children, compared to controls have increased regional GM volume in bilateral sensorimotor and right posterior temporal cortices and decreased GM volume in the right parahippocampal gyrus. GM volumes were highly correlated with IQ indices. The present work is a case study of a group of BIF children showing that BIF is associated with abnormal cortical development in brain areas that have a pivotal role in motor, learning, and behavioral processes. Our findings, although allowing for little generalization to the general population, contribute to the very limited knowledge in this field. Future longitudinal MR studies will be useful in verifying whether cortical features can be modified over time even in association with rehabilitative intervention.

Abnormal cortical growth in schizophrenia targets normative modules of synchronized development

BACKGROUND

Schizophrenia is a disorder of brain connectivity and altered neurodevelopmental processes. Cross-sectional case-control studies in different age groups have suggested that deficits in cortical thickness in childhood-onset schizophrenia may normalize over time, suggesting a disorder-related difference in cortical growth trajectories.

METHODS

We acquired magnetic resonance imaging scans repeated over several years for each subject, in a sample of 106 patients with childhood-onset schizophrenia and 102 age-matched healthy volunteers. Using semiparametric regression, we modeled the effect of schizophrenia on the growth curve of cortical thickness in ~80,000 locations across the cortex, in the age range 8 to 30 years. In addition, we derived normative developmental modules composed of cortical regions with similar maturational trajectories for cortical thickness in typical brain development.

RESULTS

We found abnormal nonlinear growth processes in prefrontal and temporal areas that have previously been implicated in schizophrenia, distinguishing for the first time between cortical areas with age-constant deficits in cortical thickness and areas whose maturational trajectories are altered in schizophrenia. In addition, we showed that when the brain is divided into five normative developmental modules, the areas with abnormal cortical growth overlap significantly only with the cingulo-fronto-temporal module.

CONCLUSIONS

These findings suggest that abnormal cortical development in schizophrenia may be modularized or constrained by the normal community structure of developmental modules of the human brain connectome.

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 Association Between Peer and own Aggression is Moderated by the BDNF Val-met Polymorphism

Peer antisocial behavior robustly predicts adolescents' own behavior but not all adolescents are equally vulnerable to their peers' influence and genetic factors may confer vulnerability. This study used data of n = 3081 adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine whether BDNF, a polymorphism that affects psychological functioning, moderates the association between affiliation with aggressive peers at age 10 and own aggression at age 15. A significant gene-environment interaction was found, where those who affiliated with aggressive peers in childhood showed increased risk for being aggressive in adolescence if they carried the BDNF met-met variant compared to val-val carriers. Our findings underline the importance of both biological and social factors for adolescent development.

Selective disruption of sociocognitive structural brain networks in autism and alexithymia

Autism spectrum conditions (ASC) are neurodevelopmental disorders characterized by abnormal social cognition. A core feature of ASC is disrupted Theory of Mind (ToM), our ability to take the mental perspective of others. ASC is also associated with alexithymia, a trait characterized by altered emotional interoception and empathy. Here, we applied structural MRI covariance analysis to assess whether ASC and alexithymia differentially affect structural brain networks associated with sociocognitive and socioaffective functions. Based on previous functional MRI findings, we expected disrupted ToM networks (centered on dorsomedial prefontal cortex [dmPFC], and temporo-parietal junction [TPJ]) in ASC, while alexithymia would affect networks centered on fronto-insular cortex (FI), regions associated with interoception of emotion and empathy. Relative to controls, ASC indeed showed reduced covariance in networks centered on dmPFC and TPJ, but not within FI networks. Irrespective of ASC, covariance was negatively modulated by alexithymia in networks extending from FI to posterior regions. Network findings were complemented by self-reports, indicating decreased perspective taking but normal empathic concern in ASC. Our results show divergent effects of ASC and alexithymia on inter-regional structural networks, suggesting that networks mediating socioaffective processes may be separable from networks mediating sociocognitive processing.

Impact of socio-emotional context, brain development, and pubertal maturation on adolescent risk-taking

While there is little doubt that risk-taking is generally more prevalent during adolescence than before or after, the underlying causes of this pattern of age differences have long been investigated and debated. One longstanding popular notion is the belief that risky and reckless behavior in adolescence is tied to the hormonal changes of puberty. However, the interactions between pubertal maturation and adolescent decision making remain largely understudied. In the current review, we discuss changes in decision making during adolescence, focusing on the asynchronous development of the affective, reward-focused processing system and the deliberative, reasoned processing system. As discussed, differential maturation in the structure and function of brain systems associated with these systems leaves adolescents particularly vulnerable to socio-emotional influences and risk-taking behaviors. We argue that this asynchrony may be partially linked to pubertal influences on development and specifically on the maturation of the affective, reward-focused processing system.

How environment and genes shape the adolescent brain

This article is part of a Special Issue "Puberty and Adolescence". This review provides a conceptual framework for the study of factors--in our genes and environment--that shape the adolescent brain. I start by pointing out that brain phenotypes obtained with magnetic resonance imaging are complex traits reflecting the interplay of genes and the environment. In some cases, variations in the structural phenotypes observed during adolescence have their origin in the pre-natal or early post-natal periods. I then emphasize the bidirectional nature of brain-behavior relationships observed during this period of human development, where function may be more likely to influence structure rather than vice versa. In the main part of this article, I review our ongoing work on the influence of gonadal hormones on the adolescent brain. I also discuss the importance of social context and brain plasticity on shaping the relevant neural circuits.

The social brain in adolescence: evidence from functional magnetic resonance imaging and behavioural studies

Social cognition is the collection of cognitive processes required to understand and interact with others. The term 'social brain' refers to the network of brain regions that underlies these processes. Recent evidence suggests that a number of social cognitive functions continue to develop during adolescence, resulting in age differences in tasks that assess cognitive domains including face processing, mental state inference and responding to peer influence and social evaluation. Concurrently, functional and structural magnetic resonance imaging (MRI) studies show differences between adolescent and adult groups within parts of the social brain. Understanding the relationship between these neural and behavioural observations is a challenge. This review discusses current research findings on adolescent social cognitive development and its functional MRI correlates, then integrates and interprets these findings in the context of hypothesised developmental neurocognitive and neurophysiological mechanisms.

Beyond Homophily: A Decade of Advances in Understanding Peer Influence Processes

This article reviews empirical and theoretical contributions to a multidisciplinary understanding of peer influence processes in adolescence over the past decade. Five themes of peer influence research from this decade were identified, including a broadening of the range of behaviors for which peer influence occurs, distinguishing the sources of influence, probing the conditions under which influence is amplified/attenuated (moderators), testing theoretically based models of peer influence processes (mechanisms), and preliminary exploration of behavioral neuroscience perspectives on peer influence. This review highlights advances in each of these areas, underscores gaps in current knowledge of peer influence processes, and outlines important challenges for future research.

Development of the action observation network during early adolescence: a longitudinal study

Adolescence places high demands on inter-personal interactions and, hence, on the extraction and processing of social cues. Here we assess longitudinally the development of brain activity within a network implicated in social cognition--the action observation network. We performed activation likelihood estimation meta-analyses to define regions of interest based upon the mature action observation network of adults. Using functional magnetic resonance imaging, we then examined developmental trajectories of functional brain activity within these brain regions. Using this approach, we reveal quadratic trajectories within a fronto-parietal network previously shown to demonstrate correlated morphological development.

The Gift and the Trap: Working the “Teen Brain” Into Our Concept of Youth

Progressive developments in scanning technologies over the last decade have led to a surge of new research into the structure and function of the brain and into differences between the brains of teenagers and other adults. This work has not been free of controversy, notably around the question of deficits in the capacity of young people concerning risk-taking behavior. In a previous article, Michael Males mounted a challenge to this body of work, arguing that it exaggerated the propensity of young people to take risks and ignored the impact of external contextual and sociological factors. In responding to Males’s article, this article not only supports his concern about deficit models of adolescence but also explores the way that the new brain science takes us beyond the century-old binary between biological determinism and social constructionism. It calls for renewed scholarly effort to develop theory and discourse that will allow us to think about young people’s responses in terms of the interaction between biology, experience and social context, and individual agency.

Adolescent development and juvenile justice

Although justice system policy and practice cannot, and should not, be dictated solely by studies of adolescent development, the ways in which we respond to juvenile offending should be informed by the lessons of developmental science. This review begins with a brief overview of the history, rationale, and workings of the American juvenile justice system. Following this, I summarize findings from studies of brain, cognitive, and psychosocial development in adolescence that have implications for the treatment of juveniles in the justice system. The utility of developmental science in this context is illustrated by the application of these research findings to three fundamental issues in contemporary justice policy: the criminal culpability of adolescents, adolescents' competence to stand trial, and the impact of punitive sanctions on adolescents' development and behavior. Taken together, the lessons of developmental science offer strong support for the maintenance of a separate juvenile justice system in which adolescents are judged, tried, and sanctioned in developmentally appropriate ways.

The mirror neuron system: new frontiers

Since the discovery of mirror neurons, much effort has been invested into studying their location and properties in the human brain. Here we review these original findings and introduce the main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror system embedded into the mosaic of circuits that compose our brain? How does the mirror system contribute to communication, language and social interaction? Can the principle of mirror neurons be extended to emotions, sensations and thoughts? Papers using a wide range of methods, including single cell recordings, fMRI, TMS, EEG and psychophysics, collected in this special issue, start to give us some impressive answers.

A Social Neuroscience Perspective on Adolescent Risk-Taking

This article proposes a framework for theory and research on risk-taking that is informed by developmental neuroscience. Two fundamental questions motivate this review. First, why does risk-taking increase between childhood and adolescence? Second, why does risk-taking decline between adolescence and adulthood? Risk-taking increases between childhood and adolescence as a result of changes around the time of puberty in the brain's socio-emotional system leading to increased reward-seeking, especially in the presence of peers, fueled mainly by a dramatic remodeling of the brain's dopaminergic system. Risk-taking declines between adolescence and adulthood because of changes in the brain's cognitive control system - changes which improve individuals' capacity for self-regulation. These changes occur across adolescence and young adulthood and are seen in structural and functional changes within the prefrontal cortex and its connections to other brain regions. The differing timetables of these changes make mid-adolescence a time of heightened vulnerability to risky and reckless behavior.

Age differences in resistance to peer influence

Prior research describes the development of susceptibility to peer pressure in adolescence as following an inverted U-shaped curve, increasing during early adolescence, peaking around age 14, and declining thereafter. This pattern, however, is derived mainly from studies that specifically examined peer pressure to engage in antisocial behavior. In the present study, age differences and developmental change in resistance to peer influence were assessed using a new self-report instrument that separates susceptibility to peer pressure from willingness to engage in antisocial activity. Data from four ethnically and socioeconomically diverse samples comprising more than 3,600 males and females between the ages of 10 and 30 were pooled from one longitudinal and two cross-sectional studies. Results show that across all demographic groups, resistance to peer influences increases linearly between ages 14 and 18. In contrast, there is little evidence for growth in this capacity between ages 10 and 14 or between 18 and 30. Middle adolescence is an especially significant period for the development of the capacity to stand up for what one believes and resist the pressures of one's peers to do otherwise.