The onset of puberty: effects on the psychophysiology of defensive and appetitive motivation

Brain network connectivity during peer evaluation in adolescent females: Associations with age, pubertal hormones, timing, and status

Despite copious data linking brain function with changes to social behavior and mental health, little is known about how puberty relates to brain functioning. We investigated the specificity of brain network connectivity associations with pubertal indices and age to inform neurodevelopmental models of adolescence. We examined how brain network connectivity during a peer evaluation fMRI task related to pubertal hormones (dehydroepiandrosterone and testosterone), pubertal timing and status, and age. Participants were 99 adolescents assigned female at birth aged 9-15 (M = 12.38, SD = 1.81) enriched for the presence of internalizing symptoms. Multivariate analysis revealed that within Salience, between Frontoparietal - Reward and Cinguloopercular - Reward network connectivity were associated with all measures of pubertal development and age. Specifically, Salience connectivity linked with age, pubertal hormones, and status, but not timing. In contrast, Frontoparietal - Reward connectivity was only associated with hormones. Finally, Cinguloopercular - Reward connectivity related to age and pubertal status, but not hormones or timing. These results provide evidence that the salience processing underlying peer evaluation is jointly influenced by various indices of puberty and age, while coordination between cognitive control and reward circuitry is related to pubertal hormones, pubertal status, and age in unique ways.

The Emotionally Sensitive Child-Adverse Parenting Experiences-Allostatic (Over)Load (ESCAPE-AL) Model for the Development of Secondary Psychopathic Traits

Understanding and treatment of antisocial behavior have improved through efforts to subtype individuals based on similar risk factors and outcomes. In particular, the presence of psychopathic traits is associated with distinct etiological factors and antisocial behavior that begins early in life, is aggressive, persistent, and less likely to normalize with traditional treatments, relative to individuals low on psychopathy or its childhood precursor, callous-unemotional (CU) traits. However, important distinctions can be made within individuals with CU/psychopathic traits according to the presence of elevated anxiety symptoms and/or adverse childhood experiences, known as secondary psychopathy/CU traits. This paper provides a broad and brief overview of theory and empirical literature supporting the existence of secondary psychopathy/CU variants as a distinct subtype of childhood antisocial behavior. It outlines the Emotionally Sensitive Child-Adverse Parenting Experiences-Allostatic (Over)Load (ESCAPE-AL) model for the developmental psychopathology of secondary psychopathic/CU traits and discusses research and theory supporting this perspective. Future research directions for testing this conceptual model and its implications for assessing and treating high-risk individuals with secondary CU/psychopathic traits are discussed.

Family study of the startle reflex and event-related potentials in anticipation of predictable and unpredictable threat in adolescents and their parents

A heightened sensitivity to unpredictable threat has been identified as a potential transdiagnostic mechanism of psychopathology. The majority of supporting research has been conducted in adults, and it is unclear whether psychophysiological indicators of sensitivity to unpredictable threat are comparable in youth during developmental periods associated with increased risk for psychopathology. In addition, no studies have examined whether sensitivity to unpredictable threat is correlated between parents and their offspring. The present study examined defensive motivation (startle reflex) and attentional engagement (probe N100, P300) in anticipation of predictable and unpredictable threat in a sample of 15-year-old adolescents (N = 395) and a biological parent (N = 379). Adolescents, compared to their parents, demonstrated greater startle potentiation and probe N100 enhancement in anticipation of unpredictable threat. In addition, overall startle potentiation in anticipation of threat was correlated between the adolescents and their parents. Adolescence is a key developmental period characterized by heightened defensive motivation and attentional engagement in anticipation of both predictable and unpredictable threat. Sensitivity to threat might index is one mechanism of vulnerability that is at least partially shared between parents and their offspring.

How does psychological capital lead to better well-being for students? The roles of family support and problem-focused coping

Recent studies have shifted the attention on the beneficial role of psychological capital from workplace to academic contexts. Moreover, the mediating role of psychological capital in the effect of social support on student outcomes remains unknown. This topic has become more imperative under the pandemic. The current study aimed to investigate the impact of psychological capital on students' well-being with family support as an antecedent and problem-focused coping as a mediator. Two hundred and eighty-one students completed the questionnaire at two time points. Results of the cross-lagged mediation analysis showed that family support positively predicted psychological capital, psychological capital positively predicted problem-focused coping, and problem-focused coping predicted well-being. Moreover, the chain mediation path between family support and well-being via psychological capital and problem-focused coping was significant. The current findings identify the antecedent and underlying mechanism behind the relationship between psychological capital and well-being, providing insights into psychological capital interventions for students.

What was learned from studying the effects of early institutional deprivation

The effect of experiences in infancy on human development is a central question in developmental science. Children raised in orphanage-like institutions for their first year or so of life and then adopted into well-resourced and supportive families provide a lens on the long-term effects of early deprivation and the capacity of children to recover from this type of early adversity. While it is challenging to identify cause-and-effect relations in the study of previously institutionalized individuals, finding results that are consistent with animal experimental studies and the one randomized study of removal from institutional care support the conclusion that many of the outcomes for these children were induced by early institutional deprivation. This review examines the behavioral and neural evidence for altered executive function, declarative memory, affective disorders, reward processing, reactivity to threat, risk-taking and sensation-seeking. We then provide a brief overview of the neurobiological mechanisms that may transduce early institutional experiences into effects on brain and behavior. In addition, we discuss implications for policy and practice.

The assessment of physical risk taking: Preliminary construct validation of a new behavioral measure

Risk taking is a complex heterogeneous construct that has proven difficult to assess, especially when using behavioral tasks. We present an exploratory investigation of new measure–the Assessment of Physical Risk Taking (APRT). APRT produces a variety of different outcome scores and is designed as a comprehensive assessment of the probability of success and failure, and magnitude of reward and punishment of different types of simulated physically risky behaviors. Effects observed on the simulated behaviors are hypothesized to reflect similar effects on real world physical risks. Participants (N = 224) completed APRT in a laboratory setting, half of whom had a 1.5 s delay interposed between button presses. Exploratory analyses utilizing generalized estimating equations examined the main effects and two-way interactions among five within-subject factors, as well as two-way interactions between the within-subject factors and Delay across four APRT outcome scores. Results indicated that Injury Magnitude and Injury Probability exerted stronger effects than any of the other independent variables. Participants also completed several self-report measures of risk taking and associated constructs (e.g., sensation seeking), which were correlated with APRT scores to assess the preliminary convergent and divergent validity of the new measure. After correcting for multiple comparisons, APRT scores correlated with self-reported risk taking in thrilling, physically dangerous activities specifically, but only for those who did not have a delay between APRT responses. This promising exploratory investigation highlights the need for future studies comparing APRT to other behavioral risk taking tasks, examining the robustness of the observed APRT effects, and investigating how APRT may predict real-world physical risk taking.

Puberty drives fear learning during adolescence

Risk for adverse outcomes, including the onset of mental illness, increases during adolescence. This increase may be linked to both new exposures, such as violence at home or in the community, or to physiological changes driven by puberty. There are significant sex differences in adolescent risk, for instance, anxiety disorders are significantly more prevalent in girls than boys. Fear learning is linked to mental health and may develop during adolescence, but the role of puberty in adolescent-specific change has not yet been systematically evaluated. We conducted a longitudinal study of fear learning that tested fear-potentiated startle (FPS) in 78 children (40 girls) aged 8-16 years. Participants completed two to three visits that included a differential fear conditioning task and self-report of both pubertal status and violence exposure. We tested for effects of sex, pubertal status, and violence exposure on FPS over time with latent growth curve models. We also examined the association between FPS and later anxiety symptoms. We found significant changes in FPS to the threat cue, but not the safety cue, across visits. Higher pubertal status was significantly associated with increased FPS to threat cues at each visit, whereas sex and violence exposure were not. FPS to threat during the baseline visit also predicted later anxiety symptoms. These findings suggest that puberty drives increased fear response to threat cues similarly for girls and boys, and that this effect may not be significantly impacted by individual differences in violence exposure during early adolescence.

Anxiety in transition: Neuroendocrine mechanisms supporting the development of anxiety pathology in adolescence and young adulthood

Adolescence marks a key developmental window during which emotion dysregulation increases, along with risk for the onset of anxiety and other affect-related pathologies. Although emotion dysregulation and related pathologies normatively decline during the transition into adulthood, this does not occur for a sizable minority of individuals. Finally, sex differences in anxiety emerge during adolescence, with females developing a 2-fold increase in risk relative to males. Unfortunately, a neurobiological model of the mechanisms that cause these changes during adolescence has yet to be proposed. In the present work, we first provide brief reviews of relevant literature. Next, we outline a dual-mechanism model focused on (i) the influence of pubertal testosterone on key emotion-regulation circuitry (i.e., orbitofrontal cortex-amygdala coupling) and (ii) myelination of the fiber bundles connecting such circuitry (i.e., uncinate fasciculus). The proposed model offers a set of specific, testable hypotheses that will hopefully spur much needed cross-disciplinary research.

Sketching the Power of Machine Learning to Decrypt a Neural Systems Model of Behavior

Uncovering brain-behavior mechanisms is the ultimate goal of neuroscience. A formidable amount of discoveries has been made in the past 50 years, but the very essence of brain-behavior mechanisms still escapes us. The recent exploitation of machine learning (ML) tools in neuroscience opens new avenues for illuminating these mechanisms. A key advantage of ML is to enable the treatment of large data, combing highly complex processes. This essay provides a glimpse of how ML tools could test a heuristic neural systems model of motivated behavior, the triadic neural systems model, which was designed to understand behavioral transitions in adolescence. This essay previews analytic strategies, using fictitious examples, to demonstrate the potential power of ML to decrypt the neural networks of motivated behavior, generically and across development. Of note, our intent is not to provide a tutorial for these analyses nor a pipeline. The ultimate objective is to relate, as simply as possible, how complex neuroscience constructs can benefit from ML methods for validation and further discovery. By extension, the present work provides a guide that can serve to query the mechanisms underlying the contributions of prefrontal circuits to emotion regulation. The target audience concerns mainly clinical neuroscientists. As a caveat, this broad approach leaves gaps, for which references to comprehensive publications are provided.

Defence response mobilization in response to provocation or imagery of interoceptive sensations in adolescents with chronic pain: a study protocol

Introduction

Fear of pain seems to be a key factor in the development and maintenance of chronic pain and pain-related disability. Interoceptive fear conditioning is assumed to constitute an important mechanism in the origins and maintenance of fear of pain. If conditioned stimuli such as internal bodily sensations are repeatedly paired with pain (unconditioned stimulus), they in turn elicit a conditioned fear response, including defence mobilization such as startle modulation and changes in heart rate and electrodermal activity. Research into emotional imagery suggests that defensive responses can also be elicited through imagery of fear scripts.

Objectives

We present 2 novel paradigms adapted from research on anxiety disorders, which allow to test, if perceived or imagined sensations locally proximal to the main pain location trigger heightened defence response mobilization in adolescents with chronic headaches and abdominal pain.

Methods

The provocation paradigm includes the anticipation and provocation of locally proximal and locally distal interoceptive sensations through disorder-specific muscle tensing tasks (tightening the neck or the abdominal muscles). The imagery paradigm includes 3 imagery scripts (standard neutral, standard fear, and disorder-specific). Startle probes are presented in both paradigms. Defence response mobilization is assessed using psychophysiological measures (startle response modulation, skin conductance level, and heart rate), as well as self-reported measures of fear.

Perspective

The paradigms will give insight into the defence response of adolescents with chronic pain, when confronted with or imagining interoceptive sensations. Results may inform the improvement of clinical interventions aimed to decrease fear of bodily sensations such as interoceptive exposure or interoceptive imagery exposure.

Appetitive startle modulation in the human laboratory predicts Cannabis craving in the natural environment

RATIONALE

Drug-related cues evoke craving and stimulate motivational systems in the brain. The acoustic startle reflex captures activation of these motivational processes and affords a unique measure of reactivity to drug cues.

OBJECTIVES

This study examined the effects of cannabis-related cues on subjective and eye blink startle reactivity in the human laboratory and tested whether these effects predicted youth's cue-elicited cannabis craving in the natural environment.

METHODS

Participants were 55 frequent cannabis users, ages 16 to 24 years (M = 19.9, SD = 1.9; 55% male; 56% met criteria for cannabis dependence), who were recruited from a clinical trial to reduce cannabis use. Eye blink electromyographic activity was recorded in response to acoustic probes that elicited startle reactivity while participants viewed pleasant, unpleasant, neutral, and cannabis picture cues. Following the startle assessment, participants completed an ecological momentary assessment protocol that involved repeated assessments of cue-elicited craving in real time in their real-world environments.

RESULTS

Multilevel models included the presence or absence of visible cannabis cues in the natural environment, startle magnitude, and the cross-level interaction of cues by startle to test whether cue-modulated startle reactivity in the laboratory was associated with cue-elicited craving in the natural environment. Analyses showed that cannabis-related stimuli evoked an appetitive startle response pattern in the laboratory, and this effect was associated with increased cue-elicited craving in the natural environment, b = - 0.15, p = .022, 95% CI [- 0.28, - 0.02]. Pleasant stimuli also evoked an appetitive response pattern, but in this case, blunted response was associated with increased cue-elicited craving in the natural environment, b = 0.27, p < .001, 95% CI [0.12, 0.43].

CONCLUSIONS

Our findings support cue-modulated startle reactivity as an index of the phenotypic expression of cue-elicited cannabis craving.

Measuring and preventing alcohol use and related harm among young people in Asian countries: a thematic review

Background

The paper reviews alcohol consumption patterns and alcohol-related social and health issues among 15–29-year old young people in Asian countries, and discusses strategies for preventing and controlling alcohol use and related harms.

Methods

We searched Google Scholar, PubMed, and Web of Science for reports, reviews and journal articles published in English between 1st Jan 1990 and 31st August 2016.

Results

Forty-one reports, reviews and journal papers were identified and included in the final review. The current drinking levels and prevalence among young people are markedly different between eight included Asian countries, ranging from 4.2% in Malaysia to 49.3% in China. In a majority of the selected Asian countries, over 15% of total deaths among young men and 6% among young women aged 15–29 years are attributable to alcohol use. Alcohol use among young people is associated with a number of harms, including stress, family violence, injuries, suicide, and sexual and other risky behaviours. Alcohol policies, such as controlling sales, social supply and marketing, setting up/raising a legal drinking age, adding health warning labels on alcohol containers, and developing a surveillance system to monitor drinking pattern and risky drinking behaviour, could be potential means to reduce harmful use of alcohol and related harm among young people in Asia.

Conclusions

The review reveals that drinking patterns and behaviours vary across eight selected Asian countries due to culture, policies and regional variations. The research evidence holds substantial policy implications for harm reduction on alcohol drinking among young people in Asian countries -- especially for China, which has almost no alcohol control policies at present.

The Increased Sex Differences in Susceptibility to Emotional Stimuli during Adolescence: An Event-Related Potential Study

The present study investigated how pubertal development and sex interact to influence humans’ emotion susceptibility during adolescence. Event-related potentials were recorded for highly emotional, mildly emotional and neutral stimuli in positive and negative blocks, when 73 adolescents (36 pre-/early pubertal students, 19 boys, 10–12 years old; 37 mid-/late pubertal students, 18 boys, 11–13 years old) performed an implicit emotion task. Behavioral analysis showed higher positive mood ratings for pre-/early compared to mid-/late pubertal subjects, irrespective of sex and block. ERP analysis demonstrated increasing Late Positive Potential (LPP) amplitudes from neutral, Mildly Positive (MP) to Highly Positive (HP) stimuli in pre-/early pubertal, but not in mid-/late pubertal adolescents. However, girls exhibited higher P3a amplitudes during mid-/late relative to pre-/early puberty for negative stimuli irrespective of intensity; while this puberty effect was absent in boys. In addition, girls compared to boys exhibited a more pronounced LPP enhancement effect for Highly Negative (HN) stimuli and a lower threshold of responding to negative stimuli in P3b amplitudes, regardless of puberty. These results suggest that, though there is a puberty-independent sensitivity to negative stimuli in girls relative to boys, puberty selectively intensifies girls’ attention bias for negative stimuli and reduces experiential sensitivity to positive stimuli in both sexes. The implication of these results for the sex-related psychopathology during adolescence were discussed.

Unpredictability increases the error-related negativity in children and adolescents

The error-related negativity (ERN) is a response-locked component in the event-related potential observed asa negative deflection 50-100ms following the commission of an error. An unpredictable context has been shown to potentiate amygdala activity, attentional bias toward threat, and the ERN in adults. However, it is unclear whether the impact of unpredictability on the ERN is also observed in children and adolescents. In a sample of 32 9-17year-old participants, we examined the influence of a task-irrelevant unpredictable context on neural response to errors. Participants completed a flanker task designed to elicit the ERN, while simultaneously being exposed to task-irrelevant tone sequences with either predictable or unpredictable timing. Unpredictable tones were rated as more anxiety provoking compared to the predictable tones. Fewer errors were made during unpredictable relative to predictable tones. Moreover, the ERN-but not the correct response negativity (CRN) or stimulus-locked N200-was potentiated during the unpredictable relative to predictable tones. The current study replicates and extends previous findings by demonstrating that an unpredictable context can increase task performance and selectively potentiate the ERN in children and adolescents. ERN magnitude can be modulated by environmental factors suggesting enhanced error processing in unpredictable contexts.

Acceptance and commitment therapy universal prevention program for adolescents: a feasibility study

BACKGROUND

There is a need to prevent anxiety and depression in young people and mindfulness contains important emotion regulation strategies. Acceptance and commitment therapy (ACT), a mindfulness-based therapy, has yet to be evaluated as a prevention program, but has demonstrated an ability to reduce symptoms of anxiety and depression in adult and adolescent populations. This study examines the feasibility of using an ACT-based prevention program in a sample of year 10 (aged 14-16 years) high school students from Sydney, Australia.

METHODS

Participants were allocated to either their usual classes or to the ACT-based intervention. Participants were followed for a period of 5 months post-intervention and completed the Flourishing Scale, Depression Anxiety Stress Scale, and a program evaluation questionnaire. Analyses were completed using intention-to-treat mixed models for repeated measures.

RESULTS

The results indicated that the intervention was acceptable to students and feasible to administer in a school setting. There were no statistically significant differences between the conditions, likely due to the small sample size (N = 48). However, between-group effect sizes demonstrated small to large differences for baseline to post-intervention mean scores and medium to large differences for baseline to follow-up mean scores, all favouring the ACT-based condition.

CONCLUSION

The results suggest that an ACT-based school program has potential as a universal prevention program and merits further investigation in a larger trial. Trial registration Australian New Zealand Clinical Trials Registry. Trial ID: ACTRN12616001383459. Registered 06/10/2016. Retrospectively registered.

Pubertal development and anxiety risk independently relate to startle habituation during fear conditioning in 8-14 year-old females

Reduced habituation to aversive stimuli has been observed during adolescence and may reflect an underlying mechanism of vulnerability for anxiety disorders. This study examined the startle reflex during a fear-learning task in 54 8-14-year-old girls. We examined the relationship between mean startle, startle habituation, pubertal development, and two measures linked to risk for anxiety: behavioral inhibition system (BIS) and the error-related negativity (ERN). Puberty, BIS, and the ERN were unrelated to mean startle; however, each measure modulated startle habituation. Greater pubertal development was associated with reduced startle habituation across the CS+ and CS-. Higher BIS related to a larger ERN, and both were associated with reduced startle habituation specifically to the CS+. All effects were independent of each other. Findings suggest that puberty alters habituation of defense system activation to both threat and safety cues, and this is independent of risk for anxiety, which uniquely impacts habituation to threat cues.

Early Pubertal Timing and Childhood Family Adversity Interact to Predict Newlywed Women's Anxiety Symptoms

The contextual amplification hypothesis posits that girls' early pubertal timing will predict anxiety and depression symptoms most strongly when early puberty occurs under adverse conditions. Research supporting this hypothesis has consistently linked early pubertal timing occurring in adverse contexts to symptoms during adolescence, but little is known about the link to adult symptoms. The present study examined the extent to which women's reports of early pubertal timing and childhood family adversity interact to predict symptoms of anxiety and depression during the first two years of marriage. Married women (N = 226) completed questionnaires within 7 months into their first marriage (Time 1) and approximately 19 months later (Time 2). Analyses indicated that at both Time 1 and 2, women's reports of earlier pubertal timing predicted anxiety symptoms only when women reported a history of greater childhood family adversity. Additional analyses indicated that the interaction of earlier pubertal timing and greater childhood family adversity predicted symptoms of traumatic intrusions and panic, but not social anxiety, at Time 1, and panic symptoms at Times 1 and 2. These findings expand our understanding of the relation of early pubertal timing to adult emotional health and the family conditions that moderate this relation.

Postauricular reflexes elicited by soft acoustic clicks and loud noise probes: Reliability, prepulse facilitation, and sensitivity to picture contents

The startle blink reflex is facilitated during early picture viewing, then inhibited by attention during pleasant and aversive pictures compared to neutral pictures, and finally potentiated during aversive pictures specifically. However, it is unclear whether the postauricular reflex, which is elicited by the same loud acoustic probe as the startle blink reflex but enhanced by appetitive instead of defensive emotion, has the same pattern and time course of emotional modulation. We examined this issue in a sample of 90 undergraduates using serially presented soft acoustic clicks that elicited postauricular (but not startle blink) reflexes in addition to standard startle probes. Postauricular reflexes elicited by both clicks and probes correlated during food and nurturant contents, during which they were potentiated compared to neutral pictures, suggesting clicks effectively elicit emotionally modulated postauricular reflexes. The postauricular reflex was initially facilitated during the first 500 ms of picture processing but was larger during pleasant than neutral pictures throughout picture processing, with larger effect sizes during the latter half of picture processing. Across reflexes and eliciting stimuli, measures of emotional modulation had higher coefficient alphas than magnitudes during specific picture contents within each valence, indicating that only emotional modulation measures assess higher-order appetitive or defensive processing.

Positive Emotion Specificity and Mood Symptoms in an Adolescent Outpatient Sample

Research on positive emotion disturbance has gained increasing attention, yet it is not clear which specific positive emotions are affected by mood symptoms, particularly during the critical period of adolescence. This is especially pertinent for identifying potential endophenotypic markers associated with mood disorder onset and course. The present study examined self-reported discrete positive and negative emotions in association with clinician-rated manic and depressive mood symptoms in a clinically and demographically diverse group of 401 outpatient adolescents between 11-18 years of age. Results indicated that higher self reported joy and contempt were associated with increased symptoms of mania, after controlling for symptoms of depression. Low levels of joy and high sadness uniquely predicted symptoms of depression, after controlling for symptoms of mania. Results were independent of age, ethnicity, gender and bipolar diagnosis. These findings extend work on specific emotions implicated in mood pathology in adulthood, and provide insights into associations between emotions associated with goal driven behavior with manic and depressive mood symptom severity in adolescence. In particular, joy was the only emotion associated with both depressive and manic symptoms across adolescent psychopathology, highlighting the importance of understanding positive emotion disturbance during adolescent development.

The relations of age and pubertal development with cortisol and daily stress in youth at clinical risk for psychosis

BACKGROUND

Prodromal syndromes often begin in adolescence - a period of neurodevelopmental changes and heightened stress sensitivity. Research has shown elevated stress and cortisol in individuals at clinical high risk (CHR) for psychosis. This cross-sectional study examined relations of age and pubertal status with cortisol and self-reported stress in healthy controls (HCs) and CHR adolescents. It was hypothesized that the relations of age and pubertal stage with cortisol and stress would be more pronounced in CHR youth.

METHODS

Participants were 93 HCs and 348 CHR adolescents from the North American Prodrome Longitudinal Study (NAPLS). At baseline, measures of stress (Daily Stress Inventory - DSI), Tanner stage (TS), and salivary cortisol were obtained.

RESULTS

ANCOVA revealed increased DSI scores with age for both groups, and higher DSI scores in CHR adolescents than HCs, with a more pronounced difference for females. Contrary to prediction, with age controlled, HCs showed greater TS-related DSI increases. Analysis of cortisol showed no significant interactions, but a main effect of age and a trend toward higher cortisol in the CHR group. Correlations of cortisol with TS were higher in HC than CHR group.

CONCLUSIONS

Stress measures increased with age in HC and CHR adolescents, and DSI scores also increased with TS in HCs. The results do not support a more pronounced age or TS increase in stress measures in CHR adolescents, but instead suggest that stress indices tend to be elevated earlier in adolescence in the CHR group. Potential determinants of findings and future directions are discussed.

The dual systems model: Review, reappraisal, and reaffirmation

According to the dual systems perspective, risk taking peaks during adolescence because activation of an early-maturing socioemotional-incentive processing system amplifies adolescents' affinity for exciting, pleasurable, and novel activities at a time when a still immature cognitive control system is not yet strong enough to consistently restrain potentially hazardous impulses. We review evidence from both the psychological and neuroimaging literatures that has emerged since 2008, when this perspective was originally articulated. Although there are occasional exceptions to the general trends, studies show that, as predicted, psychological and neural manifestations of reward sensitivity increase between childhood and adolescence, peak sometime during the late teen years, and decline thereafter, whereas psychological and neural reflections of better cognitive control increase gradually and linearly throughout adolescence and into the early 20s. While some forms of real-world risky behavior peak at a later age than predicted, this likely reflects differential opportunities for risk-taking in late adolescence and young adulthood, rather than neurobiological differences that make this age group more reckless. Although it is admittedly an oversimplification, as a heuristic device, the dual systems model provides a far more accurate account of adolescent risk taking than prior models that have attributed adolescent recklessness to cognitive deficiencies.

Child maltreatment, callous-unemotional traits, and defensive responding in high-risk children: An investigation of emotion-modulated startle response

Child maltreatment is associated with disruptions in physiological arousal, emotion regulation, and defensive responses to cues of threat and distress, as well as increased risk for callous unemotional (CU) traits and externalizing behavior. Developmental models of CU traits have focused on biological and genetic risk factors that contribute to hypoarousal and antisocial behavior, but have focused less on environmental influences (Blair, 2004; Daversa, 2010; Hare, Frazell, & Cox, 1978; Krueger, 2000; Shirtcliff et al., 2009; Viding, Fontaine, & McCrory, 2012). The aim of the present investigation was to measure the independent and combined effects of child maltreatment and high CU traits on emotion-modulated startle response in children. Participants consisted of 132 low-income maltreated (n = 60) and nonmaltreated (n = 72) children between 8 and 12 years old who attended a summer camp program. Acoustic startle response (ASR) was elicited in response to a 110-dB 50-ms probe while children viewed a slideshow of pleasant, neutral, and unpleasant IAPS images. Maltreatment status was assessed through examination of Department of Human Services records. CU traits were measured using counselor reports from the Inventory of Callous and Unemotional Traits (Frick, 2004), and conduct problems were measured using counselor and child self-report. We found no significant differences in emotion-modulated startle in the overall sample. However, significant differences in ASR by maltreatment status, maltreatment subtype, and level of CU traits were apparent. Results indicated differential physiological responses for maltreated and nonmaltreated children based on CU traits, including a pathway of hypoarousal for nonmaltreated/high CU children that differed markedly from a more normative physiological trajectory for maltreated/high CU children. Further, we found heightened ASR for emotionally and physically neglected children with high CU and elevated antisocial behavior in these children. Results provide further support for differential trajectories by which experience and biology may influence the development of antisocial behavior in youth and highlight potential avenues for intervention.

Child maltreatment, callous-unemotional traits, and defensive responding in high-risk children: An investigation of emotion-modulated startle response

Child maltreatment is associated with disruptions in physiological arousal, emotion regulation, and defensive responses to cues of threat and distress, as well as increased risk for callous unemotional (CU) traits and externalizing behavior. Developmental models of CU traits have focused on biological and genetic risk factors that contribute to hypoarousal and antisocial behavior, but have focused less on environmental influences (Blair, 2004; Daversa, 2010; Hare, Frazell, & Cox, 1978; Krueger, 2000; Shirtcliff et al., 2009; Viding, Fontaine, & McCrory, 2012). The aim of the present investigation was to measure the independent and combined effects of child maltreatment and high CU traits on emotion-modulated startle response in children. Participants consisted of 132 low-income maltreated (n = 60) and nonmaltreated (n = 72) children between 8 and 12 years old who attended a summer camp program. Acoustic startle response (ASR) was elicited in response to a 110-dB 50-ms probe while children viewed a slideshow of pleasant, neutral, and unpleasant IAPS images. Maltreatment status was assessed through examination of Department of Human Services records. CU traits were measured using counselor reports from the Inventory of Callous and Unemotional Traits (Frick, 2004), and conduct problems were measured using counselor and child self-report. We found no significant differences in emotion-modulated startle in the overall sample. However, significant differences in ASR by maltreatment status, maltreatment subtype, and level of CU traits were apparent. Results indicated differential physiological responses for maltreated and nonmaltreated children based on CU traits, including a pathway of hypoarousal for nonmaltreated/high CU children that differed markedly from a more normative physiological trajectory for maltreated/high CU children. Further, we found heightened ASR for emotionally and physically neglected children with high CU and elevated antisocial behavior in these children. Results provide further support for differential trajectories by which experience and biology may influence the development of antisocial behavior in youth and highlight potential avenues for intervention.

A dual-axis approach to understanding neuroendocrine development

This introduction sets out to present a series of paper about a novel perspective regarding stress and sex hormones, or what the authors within this special issue term "coupling" of hypothalamic-pituitary-adrenal and--gonadal axes. This view postulates that these axes do not necessarily operate in opposition, but can operate together as evidenced empirically as a positive within-person association between stress hormones like cortisol or sex hormones like testosterone. A wealth of papers within the special issue demonstrate positive coupling across acute, diurnal, basal, and longitudinal timeframes and across several different types of contexts. Reviews were meant to challenge whether this was physiologically plausible. Consistently, sophisticated statistical models were utilized in order to show a template for how to model positive coupling and to ensure that coupling was a within-person phenomenon. We cautiously considered positive coupling until the consistency of observing coupling was robust enough for us to consider challenging the prevailing oppositional view of these axes. We do so to acknowledge that there are contexts, moments and stages in which the function of these axes should work together: for example when contexts are both stressful and challenging or at developmental stages (like adolescence) in which the youth must grow up despite the storm and stress of youth. We hope that by putting forward a functional dual-axis approach, the field will be able to consider when and how these axes work together.

Evidence for a vestigial pinna-orienting system in humans

Although some people can voluntarily move their ears, overt reflexive control of the pinnae has been lost during the course of primate evolution. Humans and apes do not move their ears to express emotion, they do not defensively retract them when startled, and they do not point them at novel, salient, or task-relevant stimuli. Nevertheless, it is the thesis of this review that neural circuits for pinna orienting have survived in a purely vestigial state for over 25 million years. There are three lines of evidence: (1) Shifting the eyes hard to one side is accompanied by electromyographic (EMG) activity in certain ear muscles and by a barely visible (2-3 mm) curling of the dorsal edge of the pinna. (2) The capture of attention by a novel, unexpected sound emanating from behind and to one side has been found to trigger a weak EMG response in the muscle behind the corresponding ear. (3) Reflexive EMG bursts recorded during a selective attention task suggested that subjects were unconsciously attempting to orient their ears toward the relevant sounds. In addition to pinna orienting, the possibility that pinna startle might have survived in a vestigial state is also considered. It is suggested that the postauricular reflex to sudden, intense sounds constitutes a vestigial startle response, but that the reflex arc is dominated by a pathway that bypasses the main organizing center for startle.

Emergence of sex differences in the development of substance use and abuse during adolescence

Substance use and abuse begin during adolescence. Male and female adolescent humans initiate use at comparable rates, but males increase use faster. In adulthood, more men than women use and abuse addictive drugs. However, some women progress more rapidly from initiation of use to entry into treatment. In animal models, adolescent males and females consume addictive drugs similarly. However, reproductively mature females acquire self-administration faster, and in some models, escalate use more. Sex/gender differences exist in neurobiologic factors mediating both reinforcement (dopamine, opioids) and aversiveness (CRF, dynorphin), as well as intrinsic factors (personality, psychiatric co-morbidities) and extrinsic factors (history of abuse, environment especially peers and family) which influence the progression from initial use to abuse. Many of these important differences emerge during adolescence, and are moderated by sexual differentiation of the brain. Estradiol effects which enhance both dopaminergic and CRF-mediated processes contribute to the female vulnerability to substance use and abuse. Testosterone enhances impulsivity and sensation seeking in both males and females. Several protective factors in females also influence initiation and progression of substance use including hormonal changes of pregnancy as well as greater capacity for self-regulation and lower peak levels of impulsivity/sensation seeking. Same sex peers represent a risk factor more for males than females during adolescence, while romantic partners increase risk for women during this developmental epoch. In summary, biologic factors, psychiatric co-morbidities as well as personality and environment present sex/gender-specific risks as adolescents begin to initiate substance use.

On the Development of Implicit and Control Processes in Relation to Substance Use in Adolescence

Adolescence is a period in which brain structures involved in motivation and cognitive control continue to develop and also a period in which many youth begin substance use. Dual-process models propose that, among substance users, implicit or automatically activated neurocognitive processes gain in relative influence on substance use behavior, while the influence of cognitive control or reflective processes weakens. There is evidence that a variety of implicit cognitive processes, such as attentional bias, biased action tendencies (approach bias), memory bias and at a neural level, cue reactivity, are associated with adolescent substance use. The impact of these implicit processes on the further development of addictive behaviors appears to depend on moderating factors, such as (premorbid) executive control functions. Clear negative effects of adolescent substance use on executive control functions generally have not been found using behavioral tasks, although some studies have identified subtle and specific effects on cognitive functioning.

Individual change and the timing and onset of important life events

Researchers are often interested in studying how the timing of a specific event affects concurrent and future development. When faced with such research questions there are multiple statistical models to consider and those models are the focus of this paper as well as their theoretical underpinnings and assumptions regarding the nature of the effect of the event on the developmental process. We discuss three models, all variants of growth models specified within the multilevel modeling framework, which conceptualize the developmental process and the effect of the event in different ways. These models include the growth model with a time-invariant covariate, the growth model with a time-varying covariate, and the spline growth model. After discussing the models in detail, we applied these models to longitudinal data from the Berkeley Growth Study to examine cognitive changes during infancy and the effect of independent sitting on those changes. Results suggest that research conclusions depend on the model chosen and how certain results can be misconstrued unless the model accurately reflects the research questions. Recommendations and additional non-traditional models are discussed.

The impact of early neglect on defensive and appetitive physiology during the pubertal transition: a study of startle and postauricular reflexes

This study tested the effect of early neglect on defensive and appetitive physiology during puberty. Emotion-modulated reflexes, eye-blink startle (defensive) and postauricular (appetitive), were measured in 12-to-13-year-old internationally adopted youth (from foster care or from institutional settings) and compared to non-adopted US born controls. Startle Reflex: adopted youth displayed lower overall startle amplitude across all valences and startle potentiation to negative images was negatively related to severity of pre-adoption neglect. Postauricular reflex (PAR): adopted youth showed larger PAR magnitude across all valences. Puberty: adopted youth showed diminished PAR potentiation to positive images and startle potentiation during mid/late puberty versus the opposite pattern in not-adopted. Early neglect was associated with blunted fast defensive reflexes and heightened fast appetitive reflexes. After puberty, early neglected youth showed physiological hyporeactivity to threatening and appetitive stimuli versus heightened reactivity in not adopted youth. Behavioral correlates in this sample and possible neurodevelopmental mechanisms of psychophysiological differences are discussed.

The importance of puberty for adolescent development: conceptualization and measurement

How and why are teenagers different from children and adults? A key question concerns the ways in which pubertal development shapes psychological changes in adolescence directly through changes to the brain and indirectly through the social environment. Empirical work linking pubertal development to adolescent psychological function draws from several different perspectives, often with varying approaches and a focus on different outcomes and mechanisms. The main themes concern effects of atypical pubertal timing on behavior problems during adolescence, effects of pubertal status (and associated hormones) on normative changes in behaviors that can facilitate or hinder development (especially risk-taking, social reorientation, and stress responsivity), and the role of puberty in triggering psychopathology in vulnerable individuals. There is also interest in understanding the ways in which changes in the brain reflect pubertal processes and underlie psychological development in adolescence. In this chapter, we consider the ways that puberty might affect adolescent psychological development, and why this is of importance to developmentalists. We describe the processes of pubertal development; summarize what is known about pubertal influences on adolescent development; consider the assumptions that underlie most work and the methodological issues that affect the interpretation of results; and propose research directions to help understand paths from puberty to behavior. Throughout, we emphasize the importance of pubertal change in all aspects of psychological development, and the ways in which puberty represents an opportunity to study the interplay of biological and social influences.

The effects of violence exposure on the development of impulse control and future orientation across adolescence and early adulthood: Time-specific and generalized effects in a sample of juvenile offenders

Impulse control and future orientation increase across adolescence, but little is known about how contextual factors shape the development of these capacities. The present study investigates how stress exposure, operationalized as exposure to violence, alters the developmental pattern of impulse control and future orientation across adolescence and early adulthood. In a sample of 1,354 serious juvenile offenders, higher exposure to violence was associated with lower levels of future orientation at age 15 and suppressed development of future orientation from ages 15 to 25. Increases in witnessing violence or victimization were linked to declines in impulse control 1 year later, but only during adolescence. Thus, beyond previous experiences of exposure to violence, witnessing violence and victimization during adolescence conveys unique risk for suppressed development of self-regulation.

A Two-Hit Model of Autism: Adolescence as the Second Hit

Adolescence brings dramatic changes in behavior and neural organization. Unfortunately, for some 30% of individuals with autism, there is marked decline in adaptive functioning during adolescence. We propose a two-hit model of autism. First, early perturbations in neural development function as a "first hit" that sets up a neural system that is "built to fail" in the face of a second hit. Second, the confluence of pubertal hormones, neural reorganization, and increasing social demands during adolescence provides the "second hit" that interferes with the ability to transition into adult social roles and levels of adaptive functioning. In support of this model, we review evidence about adolescent-specific neural and behavioral development in autism. We conclude with predictions and recommendations for empirical investigation about several domains in which developmental trajectories for individuals with autism may be uniquely deterred in adolescence.

Pubertal testosterone influences threat-related amygdala-orbitofrontal cortex coupling

Growing evidence indicates that normative pubertal maturation is associated with increased threat reactivity, and this developmental shift has been implicated in the increased rates of adolescent affective disorders. However, the neural mechanisms involved in this pubertal increase in threat reactivity remain unknown. Research in adults indicates that testosterone transiently decreases amygdala-orbitofrontal cortex (OFC) coupling. Consequently, we hypothesized that increased pubertal testosterone disrupts amygdala-OFC coupling, which may contribute to developmental increases in threat reactivity in some adolescents. Hypotheses were tested in a longitudinal study by examining the impact of testosterone on functional connectivity. Findings were consistent with hypotheses and advance our understanding of normative pubertal changes in neural systems instantiating affect/motivation. Finally, potential novel insights into the neurodevelopmental pathways that may contribute to adolescent vulnerability to behavioral and emotional problems are discussed.

Exciting fear in adolescence: does pubertal development alter threat processing?

Adolescent development encompasses an ostensible paradox in threat processing. Risk taking increases dramatically after the onset of puberty, contributing to a 200% increase in mortality. Yet, pubertal maturation is associated with increased reactivity in threat-avoidance systems. In the first part of this paper we propose a heuristic model of adolescent affective development that may help to reconcile aspects of this paradox, which focuses on hypothesized pubertal increases in the capacity to experience (some) fear-evoking experiences as an exciting thrill. In the second part of this paper, we test key features of this model by examining brain activation to threat cues in a longitudinal study that disentangled pubertal and age effects. Pubertal increases in testosterone predicted increased activation to threat cues, not only in regions associated with threat avoidance (i.e., amygdala), but also regions associated with reward pursuit (i.e., nucleus accumbens). These findings are consistent with our hypothesis that puberty is associated with a maturational shift toward more complex processing of threat cues--which may contribute to adolescent tendencies to explore and enjoy some types of risky experiences.

Different patterns of puberty effect in neural oscillation to negative stimuli: sex differences

The present study investigated the impact of puberty on sex differences in neural sensitivity to negative stimuli. Event-related oscillation technique was used. Because girls are more vulnerable to affective disturbances than boys during adolescence, it was hypothesized that puberty exerts different influences on neural sensitivity to negative stimuli in boys and girls. EEGs were recorded for highly negative (HN), mildly negative (MN) and neutral pictures, when boys and girls distinct in pubertal status performed a non-emotional distracting task. No emotion effect and its interaction with sex and puberty were observed in response latencies. However, puberty influenced the gamma-band oscillation effect for negative stimuli differently for boys and girls: Pre-pubertal boys showed a significant emotion effect for HN stimuli, whose size was decreased in pubertal boys. By contrast, there was a significant emotion effect for HN stimuli in pubertal girls but not in pre-pubertal girls. On the other hand, the size of the emotion effect for HN stimuli was similar for pre-pubertal boys and girls; while this effect was significantly more pronounced in pubertal girls compared to pubertal boys. Additionally, the size of the emotion effect in gamma oscillations decreased as a function of pubertal development during both HN and MN stimulation in boys. For girls, the emotion effect in gamma oscillations increased with pubertal development during HN stimulation. Thus, puberty is associated with reduced neural sensitivity in boys but increased sensitivity in girls, in reaction to negative stimuli. The implications of these results for the psychopathology during adolescence were discussed.

Adversity in early and mid-adolescence is associated with elevated startle responses to safety cues in late adolescence

Elevated responding to safety cues in the context of threat is associated with anxiety disorder onset, but pathways underlying such responding remain unclear. This study examined whether childhood/adolescent adversity was associated with larger startle reflexes during safe phases of a fear potentiation startle paradigm (following delivery of an aversive stimulus) that predict anxiety disorders. Participants (N = 104) came from the Youth Emotion Project, a longitudinal study of risk factors for emotional disorders. Participants with no baseline psychopathology underwent a startle modulation protocol and were assessed for childhood and adolescent adversities using a validated interview. Adolescent adversity was associated with larger startle reflexes during the safe phases following an aversive stimulus. Neither child nor adolescent adversities were associated with responding during any other phase of the protocol. These findings suggest a pathway between adolescent adversity and a risk factor for anxiety disorders wherein adolescent adversity contributes to impaired responding to safety cues.

Pubertal status associations with reward and threat sensitivities and subcortical brain volumes during adolescence

Adolescence is characterized by complex developmental processes that impact behavior, biology, and social functioning. Two such adolescence-specific processes are puberty and increases in reward sensitivity. Relations between these processes are poorly understood. The present study focused on examining unique effects of puberty, age, and sex on reward and threat sensitivities and volumes of subcortical brain structures relevant for reward/threat processing in a healthy sample of 9-18year-olds. Unlike age, pubertal status had a significant unique positive relationship with reward sensitivity. In addition, there was a trend for adolescent females to exhibit higher threat sensitivity with more advanced pubertal development and higher reward and threat sensitivity with older age. Similarly, there were significant puberty by sex interaction effects on striatal volumes, i.e., left nucleus accumbens and right pallidum. The present pattern of results suggests that pubertal development, independent of chronological age, is uniquely associated with reward hypersensitivity and with structural differences in striatal regions implicated in reward processing.

Developmental investigation of fear-potentiated startle across puberty

The goal of this study was to examine the association between affective development, puberty, and gender using the startle reflex as a marker of defensive mechanisms. Thirty-one male and thirty-five female adolescents aged ten to thirteen participated in a prospective study with up to five assessments. Longitudinal analyses revealed a significant effect of sex, with girls showing stronger fear-potentiation at all pubertal stages. Post hoc tests revealed that fear-potentiation increased in girls but not boys over the course of puberty. Furthermore, baseline startle decreased over the course of puberty. Because age was included as a covariate in all analyses, the puberty effect cannot be accounted for by age. To the best of our knowledge, this study provides the first evidence for a significant increase in fear-potentiated startle across the pubertal transition. Attribution of these changes to pubertal status rather than age has important implications for our understanding of the neurobiology of anxiety and affect regulation.

Controversies about the enhanced vulnerability of the adolescent brain to develop addiction

Adolescence, defined as a transition phase toward autonomy and independence, is a natural time of learning and adjustment, particularly in the setting of long-term goals and personal aspirations. It also is a period of heightened sensation seeking, including risk taking and reckless behaviors, which is a major cause of morbidity and mortality among teenagers. Recent observations suggest that a relative immaturity in frontal cortical neural systems may underlie the adolescent propensity for uninhibited risk taking and hazardous behaviors. However, converging preclinical and clinical studies do not support a simple model of frontal cortical immaturity, and there is substantial evidence that adolescents engage in dangerous activities, including drug abuse, despite knowing and understanding the risks involved. Therefore, a current consensus considers that much brain development during adolescence occurs in brain regions and systems that are critically involved in the perception and evaluation of risk and reward, leading to important changes in social and affective processing. Hence, rather than naive, immature and vulnerable, the adolescent brain, particularly the prefrontal cortex, should be considered as prewired for expecting novel experiences. In this perspective, thrill seeking may not represent a danger but rather a window of opportunities permitting the development of cognitive control through multiple experiences. However, if the maturation of brain systems implicated in self-regulation is contextually dependent, it is important to understand which experiences matter most. In particular, it is essential to unveil the underpinning mechanisms by which recurrent adverse episodes of stress or unrestricted access to drugs can shape the adolescent brain and potentially trigger life-long maladaptive responses.

The neurobiology of psychopathic traits in youths

Conduct disorder is a childhood behaviour disorder that is characterized by persistent aggressive or antisocial behaviour that disrupts the child's environment and impairs his or her functioning. A proportion of children with conduct disorder have psychopathic traits. Psychopathic traits consist of a callous-unemotional component and an impulsive-antisocial component, which are associated with two core impairments. The first is a reduced empathic response to the distress of other individuals, which primarily reflects reduced amygdala responsiveness to distress cues; the second is deficits in decision making and in reinforcement learning, which reflects dysfunction in the ventromedial prefrontal cortex and striatum. Genetic and prenatal factors contribute to the abnormal development of these neural systems, and social-environmental variables that affect motivation influence the probability that antisocial behaviour will be subsequently displayed.

The hypothalamic-pituitary-gonadal axis: a switch-controlled, condition-sensitive system in the regulation of life history strategies

This article is part of a Special Issue "Puberty and Adolescence". Life history theory provides an overarching framework for explaining the development of individual differences in reproductive strategies and highlights the role of familial and ecological conditions in regulating pubertal timing. Parental investment and sexual selection models afford a powerful framework for explaining the emergence of sex differences in reproductive strategies and suggest that pubertal timing in males and females is differentially sensitive to psychosocial stress. The West-Eberhard's (2003) model of switch-controlled modular systems provides the foundation for a comprehensive analysis of variation in reproductive strategies at the level of mechanism and development. Applied to puberty, this model provides a framework for explaining how genes and environments interact over development, are modulated by extant phenotypic characteristics, and operate through control of regulatory switch mechanisms across multiple levels of the hypothalamic-pituitary-gonadal axis. Taken together, life history theory, parental investment and sexual selection models, and the West-Eberhard framework enable an integrated evolutionary-developmental analysis of between-sex variation and within-sex variation in pubertal processes and their role in regulating alternative life history strategies.

Mindfulness for adolescents: a promising approach to supporting emotion regulation and preventing risky behavior

This article reviews the contextual and neuropsychological challenges of the adolescent period with particular attention to the role that universal prevention can play in moderating the harmful effects of stress. The centrality of emotion regulation skills to long-term health and wellness suggests their importance in prevention and intervention efforts for youth. Mindfulness has been shown to be an effective means of reducing stress and improving emotion balance in research with adults, although research on mindfulness with adolescents is limited. The authors present available data and describe one potentially effective program for adolescent mindfulness: Learning to BREATHE.

The neglected role of positive emotion in adolescent psychopathology

Adolescence is a developmental period characterized by elevated stress, heightened risky behaviors, and increases in psychopathology. Emotion dysregulation is a hypothesized contributor to negative outcomes and to the onset of psychopathology during adolescence. However, the dysregulation of negative emotion has been the focus of research while the literature on positive emotion in adolescent psychopathology is limited. This review highlights both the development of normative and dysregulated positive emotion during adolescence. First, the literature on normative adolescent emotional development and on negative emotional regulation is briefly reviewed, followed by a discussion of current theories of positive emotion, which are grounded in the adult literature. From a developmental perspective, the dimension of approach motivation within positive emotion is emphasized throughout and frames the review. This conceptualization guides organization of literatures on normative experiences of positive emotion in adolescence and the role of dysregulated positive emotion in adolescent psychopathology, specifically adolescent depression, anxiety, bipolar disorder, externalizing disorders and eating disorders. Last, future directions in the study of adolescent positive emotion and its regulation and the implications of highlighting approach motivation in normative and dysregulated positive emotion in adolescence are detailed.