Adolescence, brain maturation and mental health

Longitudinal Associations Between White Matter Microstructure and Psychiatric Symptoms in Youth

OBJECTIVE

Associations between psychiatric problems and white matter (WM) microstructure have been reported in youth. Yet, a deeper understanding of this relation has been hampered by a dearth of well-powered longitudinal studies and a lack of explicit examination of the bidirectional associations between brain and behavior. We investigated the temporal directionality of WM microstructure and psychiatric symptom associations in youth.

METHOD

In this observational study, we leveraged the world's largest single- and multi-site cohorts of neurodevelopment: the Generation R (GenR) and Adolescent Brain Cognitive Development Studies (ABCD) (total n scans = 11,400; total N = 5,700). We assessed psychiatric symptoms with the Child Behavioral Checklist as broad-band internalizing and externalizing scales, and as syndrome scales (eg, Anxious/Depressed). We quantified WM with diffusion tensor imaging (DTI), globally and at a tract level. We used cross-lagged panel models to test bidirectional associations of global and specific measures of psychopathology and WM microstructure, meta-analyzed results across cohorts, and used linear mixed-effects models for validation.

RESULTS

We did not identify any longitudinal associations of global WM microstructure with internalizing or externalizing problems across cohorts (confirmatory analyses) before, and after multiple testing corrections. We observed similar findings for longitudinal associations between tract-based microstructure with internalizing and externalizing symptoms, and for global WM microstructure with specific syndromes (exploratory analyses). Some cross-sectional associations surpassed multiple testing corrections in ABCD, but not in GenR.

CONCLUSION

Uni- or bi-directionality of longitudinal associations between WM and psychiatric symptoms were not robustly identified. We have proposed several explanations for these findings, including interindividual differences, the use of longitudinal approaches, and smaller effects than expected.

STUDY REGISTRATION INFORMATION

Bidirectionality Brain Function and Psychiatric Symptoms; https://doi.org/10.17605/OSF.IO/PNY92.

Hemispheric asymmetries in mental disorders: evidence from rodent studies

The brain is built with hemispheric asymmetries in structure and function to enable fast neuronal processing. In neuroimaging studies, several mental disorders have been associated with altered or attenuated hemispheric asymmetries. However, the exact mechanism linking asymmetries and disorders is not known. Here, studies in animal models of mental disorders render important insights into the etiology and neuronal alterations associated with both disorders and atypical asymmetry. In this review, the current literature of animal studies in rats and mice focusing on anxiety and fear, anhedonia and despair, addiction or substance misuse, neurodegenerative disorders as well as stress exposure, and atypical hemispheric asymmetries is summarized. Results indicate overall increased right-hemispheric neuronal activity and a left-sided behavioral bias associated with symptoms of anxiety, fear, anhedonia, behavioral despair as well as stress exposure. Addiction behavior is associated with right-sided bias and transgenic models of Alzheimer's disease indicate an asymmetrical accumulation of fibrillar plaques. Most studies focused on changes in the bilateral amygdala and frontal cortex. Across studies, two crucial factors influencing atypical asymmetries arose independently of the disorder modeled: sex and developmental age. In conclusion, animal models of mental disorders demonstrate atypical hemispheric asymmetries similar to findings in patients. Particularly, increased left-sided behavior and greater right-hemispheric activity were found across models applying stress-based paradigms. However, sex- and age-dependent effects on atypical hemispheric asymmetries are present that require further investigation. Animal models enable the analysis of hemispheric changes on the molecular level which may be most effective to detect early alterations.

Exploring the longitudinal associations of functional network connectivity and psychiatric symptom changes in youth

BACKGROUND

Functional connectivity has been associated with psychiatric problems, both in children and adults, but inconsistencies are present across studies. Prior research has mostly focused on small clinical samples with cross-sectional designs.

METHODS

We adopted a longitudinal design with repeated assessments to investigate associations between functional network connectivity (FNC) and psychiatric problems in youth (9- to 17-year-olds, two time points) from the general population. The largest single-site study of pediatric neurodevelopment was used: Generation R (N = 3,131 with data at either time point). Psychiatric symptoms were measured with the Child Behavioral Checklist as broadband internalizing and externalizing problems, and its eight specific syndrome scales (e.g., anxious-depressed). FNC was assessed with two complementary approaches. First, static FNC (sFNC) was measured with graph theory-based metrics. Second, dynamic FNC (dFNC), where connectivity is allowed to vary over time, was summarized into 5 states that participants spent time in. Cross-lagged panel models were used to investigate the longitudinal bidirectional relationships of sFNC with internalizing and externalizing problems. Similar cross-lagged panel models were run for dFNC.

RESULTS

Small longitudinal relationships between dFNC and certain syndrome scales were observed, especially for baseline syndrome scales (i.e., rule-breaking, somatic complaints, thought problems, and attention problems) predicting connectivity changes. However, no association between any of the psychiatric problems (broadband and syndrome scales) with either measure of FNC survived correction for multiple testing.

CONCLUSION

We found no or very modest evidence for longitudinal associations between psychiatric problems with dynamic and static FNC in this population-based sample. Differences in findings may stem from the population drawn, study design, developmental timing, and sample sizes.

Thrsp Gene and the ADHD Predominantly Inattentive Presentation

There are three presentations of attention-deficit/hyperactivity disorder (ADHD): the predominantly inattention (ADHD-PI), predominantly hyperactive-impulsive (ADHD-HI), and combined (ADHD-C) presentations of ADHD. These may represent distinct childhood-onset neurobehavioral disorders with separate etiologies. ADHD diagnoses are behaviorally based, so investigations into potential etiologies should be founded on behavior. Animal models of ADHD demonstrate face, predictive, and construct validity when they accurately reproduce elements of the symptoms, etiology, biochemistry, and disorder treatment. Spontaneously hypertensive rats (SHR/NCrl) fulfill many validation criteria and compare well with clinical cases of ADHD-C. Compounding the difficulty of selecting an ideal model to study specific presentations of ADHD is a simple fact that our knowledge regarding ADHD neurobiology is insufficient. Accordingly, the current review has explored a potential animal model for a specific presentation, ADHD-PI, with acceptable face, predictive, and construct validity. The Thrsp gene could be a biomarker for ADHD-PI presentation, and THRSP OE mice could represent an animal model for studying this distinct ADHD presentation.

CB2R activation ameliorates late adolescent chronic alcohol exposure-induced anxiety-like behaviors during withdrawal by preventing morphological changes and suppressing NLRP3 inflammasome activation in prefrontal cortex microglia in mice

BACKGROUND

Chronic alcohol exposure (CAE) during late adolescence increases the risk of anxiety development. Alcohol-induced prefrontal cortex (PFC) microglial activation, characterized by morphological changes and increased associations with neurons, plays a critical role in the pathogenesis of anxiety. Alcohol exposure increases NLRP3 inflammasome expression, increasing cytokine secretion by activated microglia. Cannabinoid type 2 receptor (CB2R), an essential receptor of the endocannabinoid system, regulates microglial activation and neuroinflammatory reactions. We aimed to investigate the role of CB2R activation in ameliorating late adolescent CAE-induced anxiety-like behaviors and microglial activation in C57BL/6J mice.

METHODS

Six-week-old C57BL/6J mice were acclimated for 7 days and then were administered alcohol by gavage (4 g/kg, 25 % w/v) for 28 days. The mice were intraperitoneally injected with the specific CB2R agonist AM1241 1 h before alcohol treatment. Anxiety-like behaviors during withdrawal were assessed by open field test and elevated plus maze test 24 h after the last alcohol administration. Microglial activation, microglia-neuron interactions, and CB2R and NLRP3 inflammasome-related molecule expression in the PFC were measured using immunofluorescence, immunohistochemical, qPCR, and Western blotting assays. Microglial morphology was evaluated by Sholl analysis and the cell body-to-total cell size index. Additionally, N9 microglia were activated by LPS in vitro, and the effects of AM1241 on NLRP3 and N9 microglial activation were investigated.

RESULTS

After CAE, mice exhibited severe anxiety-like behaviors during withdrawal. CAE induced obvious microglia-neuron associations, and increased expression of microglial activation markers, CB2R, and NLRP3 inflammasome-related molecules in the PFC. Microglia also showed marked filament retraction and reduction and cell body enlargement after CAE. AM1241 treatment ameliorated anxiety-like behaviors in CAE model mice, and it prevented microglial morphological changes, reduced microglial activation marker expression, and suppressed the microglial NLRP3 inflammasome activation and proinflammatory cytokine secretion induced by CAE. AM1241 suppressed the LPS-induced increase in NLRP3 inflammasome-related molecules, IL-1β release, and M1 phenotype markers (iNOS and CD86) in N9 cell, which was reversed by CB2R antagonist treatment.

CONCLUSIONS

CAE caused anxiety-like behaviors in late adolescent mice at least partly by inducing microglial activation and increasing microglia-neuron associations in the PFC. CB2R activation ameliorated these effects by preventing morphological changes and suppressing NLRP3 inflammasome activation in PFC microglia.

Age differences and brain maturation provide insight into heterogeneous results in autism spectrum disorder

Studies comparing individuals with autism spectrum disorder (ASD) to typically developing (TD) individuals have yielded inconsistent results. These inconsistencies reflect, in part, atypical trajectories of development in children and young adults with ASD compared to TD peers. These different trajectories alter group differences between children with and without ASD as they age. This paper first summarizes the disparate trajectories evident in our studies and, upon further investigation, laboratories using the same recruiting source. These studies indicated that cognition improves into adulthood typically, and is associated with the maturation of striatal, frontal, and temporal lobes, but these age-related improvements did not emerge in the young adults with ASD. This pattern - of improvement into adulthood in the TD group but not in the group with ASD - occurred in both social and non-social tasks. However, the difference between TD and ASD trajectories was most robust on a social task, face recognition. While tempting to ascribe this uneven deficit to the social differences in ASD, it may also reflect the prolonged typical development of social cognitive tasks such as face recognition into adulthood. This paper then reviews the evidence on age-related and developmental changes from other studies on ASD. The broader literature also suggests that individuals with ASD do not exhibit the typical improvements during adolescence on skills important for navigating the transition to adulthood. These skills include execution function, social cognition and communication, and emotional recognition and self-awareness. Relatedly, neuroimaging studies indicate arrested or atypical brain maturation in striatal, frontal, and temporal regions during adolescence in ASD. This review not only highlights the importance of a developmental framework and explicit consideration of age and/or stage when studying ASD, but also the potential importance of adolescence on outcomes in ASD.

Usability, Feasibility, and Effect of a Biocueing Intervention in Addition to a Moderated Digital Social Therapy-Platform in Young People With Emerging Mental Health Problems: A Mixed-Method Approach

Introduction

To optimize treatment, it is of utmost importance to take into account the myriad of biological, social, and psychological changes that young people go through during adolescence which make them more vulnerable for developing mental health problems. Biocueing, a non-invasive method to transform physiological parameters into an observable signal, could strengthen stress- and emotion regulation by cueing physiologically unusual values in daily life. The aim of this study is to investigate the usability, feasibility, and exploratory effect of biocueing in addition to ENgage YOung people earlY (ENYOY), a moderated digital social therapy-platform, in young people with emerging mental health complaints.

Methods

A user-centered mixed-method design was used. A focus group was conducted to optimize the ENYOY-platform and biocueing intervention. Biocueing was operationalized by a smartwatch and the Sense-IT app. A within-subjects design was used; 10 days for all participants 'biofeedback off' (control), followed by 10 days 'biofeedback on' (experimental). Emotional awareness and perceived stress were measured using ecological momentary assessment. Eight individuals participated. User-friendliness, usability, and acceptance were assessed using a qualitative design.

Results

Findings from the focus group resulted in several adaptations of the biocueing intervention to the ENYOY-platform and vice versa. The average measurement compliance rate was 78.8%. Level-one findings showed different individual effects on perceived stress and emotional awareness. Level-two analyses showed no overall effects on perceived stress (B = -0.020, p = 0.562) and overall positive effects on emotional awareness (B = 0.030, p = 0.048) with small effect sizes (Improvement Rate Difference = 0.05-0.35). The intervention was found to be acceptable and showed moderate usability. Participants indicated they experienced improvements in reflection on feelings and changes in behavior, such as pausing and evaluating the situation.

Conclusion

These preliminary results show that biocueing could be a promising addition to digital treatment platforms and help young people become more emotionally aware. Improvements should be made regarding the usability and acceptability of the smartwatch, as well as more extensive integration of the biocueing intervention with a digital treatment platform. It would be relevant to gain a better understanding of which individuals would benefit most from an additional biocueing intervention.

Abnormal synaptic plasticity and impaired cognition in schizophrenia

Schizophrenia (SCZ) is a severe mental illness that affects several brain domains with relation to cognition and behaviour. SCZ symptoms are typically classified into three categories, namely, positive, negative, and cognitive. The etiology of SCZ is thought to be multifactorial and poorly understood. Accumulating evidence has indicated abnormal synaptic plasticity and cognitive impairments in SCZ. Synaptic plasticity is thought to be induced at appropriate synapses during memory formation and has a critical role in the cognitive symptoms of SCZ. Many factors, including synaptic structure changes, aberrant expression of plasticity-related genes, and abnormal synaptic transmission, may influence synaptic plasticity and play vital roles in SCZ. In this article, we briefly summarize the morphology of the synapse, the neurobiology of synaptic plasticity, and the role of synaptic plasticity, and review potential mechanisms underlying abnormal synaptic plasticity in SCZ. These abnormalities involve dendritic spines, postsynaptic density, and long-term potentiation-like plasticity. We also focus on cognitive dysfunction, which reflects impaired connectivity in SCZ. Additionally, the potential targets for the treatment of SCZ are discussed in this article. Therefore, understanding abnormal synaptic plasticity and impaired cognition in SCZ has an essential role in drug therapy.

Meet Them Where They're At: Maximizing Adolescents' Engagement in Stuttering Therapy

Adolescents who stutter often pose a unique clinical challenge for clinicians. They are a population simultaneously striving for independence from adults and social connection with their peers at a time when social fears surge and lifelong habits take root. It is a time when they may seem "unmotivated" to learn and utilize new communication or coping skills related to stuttering. How can clinicians maximize adolescents' engagement in stuttering therapy to improve meaningful outcomes? The purpose of this article is to describe a transtheoretical approach to assessing adolescents' readiness to make positive changes to living with stuttering, and to provide motivational interviewing strategies that clinicians can employ to help propel adolescents toward personally significant change. These principles will be applied to the case study of a 14-year-old who stutters to demonstrate how clinicians can put this approach to work as they meet their adolescent clients "where they're at."

Applying the Transtheoretical Model to Stuttering Management Among Adolescents: Part I. Scale Development

Purpose This article is the first in a two-part series on the application of the Transtheoretical Model to stuttering management among adolescents. In this article, we describe the process of developing measures to assess stage of change (SOC) by defining behaviors of stuttering management, as well as the two primary cognitive constructs that underlie one's readiness to make behavioral change: decisional balance (DB) and situational self-efficacy (SSE). This work hinges on the ability to develop an operational definition of what it means to successfully manage or do something positive about one's stuttering. Method We used an iterative process to develop the three scales. Through qualitative analysis of key informant interview and focus group transcripts with 24 adolescents who stutter and 26 clinicians specializing in stuttering, we developed stuttering-specific SOC, DB, and SSE scales. The drafted scales were cognitively tested with nine adolescents who stutter. Results Thematic analysis yielded a three-part definition of successful stuttering management that formed the basis for the SOC scale: (a) learning and using strategies to modify speech or stuttering, (b) changing negative thoughts and attitudes regarding stuttering, and (c) talking without avoiding sounds, words, or situations. Results from this analysis support a broader view of successful stuttering management; that is, it is likely that doing so requires more than just behavior change, which has long been considered the main objective of stuttering treatment. Additional analyses yielded pros and cons of managing stuttering (62 items for the DB scale) and situations in which it is difficult to manage stuttering (39 items for the SSE scale). Conclusions Qualitative analyses provided a three-part definition of "stuttering management" and a comprehensive pool of items that would allow measurement of DB and SSE that underlie readiness to manage stuttering among adolescents. In the companion article in this two-part series, we describe the next step in scale development: exploratory scale validation of the drafted SOC, DB, and SSE scales.

Applying the Transtheoretical Model to Stuttering Management Among Adolescents: Part II. Exploratory Scale Validation

Purpose This article is the second in a two-part series on the application of the Transtheoretical Model to stuttering management among adolescents. The purpose of this article was to apply and explore the validity of newly developed Transtheoretical measures for adolescents who stutter. Method The online survey was completed by a national sample of 173 adolescents who stutter between the ages of 13 and 21 years. The multipart survey included a Stage of Change scale, Decisional Balance scale, and Situational Self-Efficacy scale. Participants also completed the Overall Assessment of the Speaker's Experience of Stuttering (OASES), either the teenage or adult version depending on the participant's age, so preliminary construct validity of the new scales could be examined. Exploratory factor analyses were conducted to determine model fit and reduce the scales to the most meaningful items. External validity of the three-part survey was examined by comparing OASES scores across stage of change as well as evaluating the functional relations between the three scales. Results Adolescents' readiness to manage stuttering could be clearly described with five discrete stages, although most of the respondents reported being in the Maintenance stage. The pros of managing stuttering reliably predicted stage placement. Internal consistency of the scales ranged from good to excellent. OASES scores differed across stages of readiness in complex but predictable ways. Conclusions These findings suggest that the Transtheoretical Model fits the target behaviors involved stuttering management among adolescents. Further examination of the application of the model to validate a stage-based framework for change among individuals who stutter is warranted.

Mesocorticolimbic Dopamine Pathways Across Adolescence: Diversity in Development

Mesocorticolimbic dopamine circuity undergoes a protracted maturation during adolescent life. Stable adult levels of behavioral functioning in reward, motivational, and cognitive domains are established as these pathways are refined, however, their extended developmental window also leaves them vulnerable to perturbation by environmental factors. In this review, we highlight recent advances in understanding the mechanisms underlying dopamine pathway development in the adolescent brain, and how the environment influences these processes to establish or disrupt neurocircuit diversity. We further integrate these recent studies into the larger historical framework of anatomical and neurochemical changes occurring during adolescence in the mesocorticolimbic dopamine system. While dopamine neuron heterogeneity is increasingly appreciated at molecular, physiological, and anatomical levels, we suggest that a developmental facet may play a key role in establishing vulnerability or resilience to environmental stimuli and experience in distinct dopamine circuits, shifting the balance between healthy brain development and susceptibility to psychiatric disease.

Psychotic like experiences among Nigerian school adolescents: Findings from the Lagos Schools Emotional and Behavioral Health Survey

AIM

This study aimed to explore the presence of psychotic like experience (PLE) symptoms and evaluate for the possible socio-demographic, family, school and mental health variables associated with clinically significant PLE symptoms in Nigeria school adolescent.

METHODS

A total of 9441 adolescents from 47 secondary schools in Lagos Nigeria completed questionnaire detailing sociodemographic, family and school related variables. Mental health was assessed with the Mini International Diagnostic Interview for children and adolescents (MINI-KID). PLE was assessed using the 16-item version of Prodromal Questionnaire (PQ-16).

RESULTS

The mean age in years was 15.6 (SD 1.5) and 50.4% were females. The mean PQ-16 score was 2.18 (SD 2.38) with 95% CI 2-15-2.21. A total of 2878 (30.5%) adolescents had no PLE symptoms while 990 (10.5%) had clinically significant PLE symptoms. The most experienced symptoms were "déjà vu" (35.5%) and loss of interest (29.6%). The variables independently associated with clinically significant PLE symptoms were "having no close friend in school" (OR 2.66, 95% CI 2.08-3.41), "often beaten by parents" (OR 1.98, 95% CI 1.67-2.34) "from a polygamous family" (OR 1.80, 95% CI 1.49-2.18), and "diagnosis of depression" (OR 1.33, 95% CI 1.09-1.63).

CONCLUSION

We have shown that PLE symptoms are relatively common in non-help seeking Nigerian school adolescents and that personal and family factors are significantly associated. Longitudinal studies will be needed to chart the path of symptoms and determinants of distress, help seeking and development of psychosis.

Maternal immune activation leads to atypical turning asymmetry and reduced DRD2 mRNA expression in a rat model of schizophrenia

Atypical asymmetries have been reported in individuals diagnosed with schizophrenia, linking higher symptom severity to weaker lateralization. Furthermore, both lateralization and schizophrenia are influenced by the dopaminergic system. However, whether a direct link between the etiology of schizophrenia and atypical asymmetries exists is yet to be investigated. In this study, we examined whether maternal immune activation (MIA), a developmental animal model for schizophrenia and known to alter the dopaminergic system, induces atypical lateralization in adolescent and adult offspring. As the dopaminergic system is a key player in both, we analyzed neuronal dopamine D2 receptor (DRD2) mRNA expression. MIA was induced by injecting pregnant rats with 10 mg/kg polyinosinic:polycytidylic (PolyI:C) at gestational day 15. Controls were injected with 0.9 % NaCl. Offspring were tested at adolescence or early adulthood for asymmetry of turning behavior in the open field test. The total number of left and right turns per animal was assessed using DeepLabCut. Strength and preferred side of asymmetry were analyzed by calculating lateralization quotients. Additionally, DRD2 mRNA expression in the prefrontal cortex of offspring at both ages was analyzed using real-time PCR. MIA was associated with a rightward turning behavior in adolescents. In adults, MIA was associated with an absence of turning bias, indicating reduced asymmetry after MIA. The analysis of DRD2 mRNA expression revealed significantly lower mRNA levels after MIA compared to controls in adolescent, but not adult animals. Our results reinforce the association between atypical asymmetries, reduced DRD2 mRNA expression, and schizophrenia. However, more preclinical research is needed.

Negative Parenting Affects Adolescent Internalizing Symptoms Through Alterations in Amygdala-Prefrontal Circuitry: A Longitudinal Twin Study

BACKGROUND

The synergic interaction of risk genes and environmental factors has been thought to play a critical role in mediating emotion-related brain circuitry function and dysfunction in depression and anxiety disorders. Little, however, is known regarding neurodevelopmental bases underlying how maternal negative parenting affects emotion-related brain circuitry linking to adolescent internalizing symptoms and whether this neurobehavioral association is heritable during adolescence.

METHODS

The effects of maternal parenting on amygdala-based emotional circuitry and internalizing symptoms were examined by using longitudinal functional magnetic resonance imaging among 100 monozygotic twins and 78 dizygotic twins from early adolescence (age 13 years) to mid-adolescence (age 16 years). The mediation effects among variables of interest and their heritability were assessed by structural equation modeling and quantitative genetic analysis, respectively.

RESULTS

Exposure to maternal negative parenting was positively predictive of stronger functional connectivity of the amygdala with the ventrolateral prefrontal cortex. This neural pathway mediated the association between negative parenting and adolescent depressive symptoms and exhibited moderate heritability (21%).

CONCLUSIONS

These findings highlight that maternal negative parenting in early adolescence is associated with the development of atypical amygdala-prefrontal connectivity in relation to internalizing depressive symptoms in mid-adolescence. Such abnormality of emotion-related brain circuitry is heritable to a moderate degree.

Do intrinsic brain functional networks predict working memory from childhood to adulthood?

Working memory (WM) is defined as the ability to maintain a representation online to guide goal‐directed behavior. Its capacity in early childhood predicts academic achievements in late childhood and its deficits are found in various neurodevelopmental disorders. We employed resting‐state fMRI (rs‐fMRI) of 468 participants aged from 4 to 55 years and connectome‐based predictive modeling (CPM) to explore the potential predictive power of intrinsic functional networks to WM in preschoolers, early and late school‐age children, adolescents, and adults. We defined intrinsic functional networks among brain regions identified by activation likelihood estimation (ALE) meta‐analysis on existing WM functional studies (ALE‐based intrinsic functional networks) and intrinsic functional networks generated based on the whole brain (whole‐brain intrinsic functional networks). We employed the CPM on these networks to predict WM in each age group. The CPM using the ALE‐based and whole‐brain intrinsic functional networks predicted WM of individual adults, while the prediction power of the ALE‐based intrinsic functional networks was superior to that of the whole‐brain intrinsic functional networks. Nevertheless, the CPM using the whole‐brain but not the ALE‐based intrinsic functional networks predicted WM in adolescents. And, the CPM using neither the ALE‐based nor whole‐brain networks predicted WM in any of the children groups. Our findings showed the trend of the prediction power of the intrinsic functional networks to cognition in individuals from early childhood to adulthood.

The ABCD study: understanding the development of risk for mental and physical health outcomes

Following in the footsteps of other large "population neuroscience" studies, the Adolescent Brain Cognitive Development℠ (ABCD) study is the largest in the U.S. assessing brain development. The study is examining approximately 11,875 youth from 21 sites from age 9 to 10 for approximately ten years into young adulthood. The ABCD Study® has completed recruitment for the baseline sample generally using a multi-stage probability sample including a stratified random sample of schools. The dataset has a wealth of measured attributes of youths and their environment, including neuroimaging, cognitive, biospecimen, behavioral, youth self-report and parent self-report metrics, and environmental measures. The initial goal of the ABCD Study was to examine risk and resiliency factors associated with the development of substance use, but the project has expanded far beyond this initial set of questions and will also greatly inform our understanding of the contributions of biospecimens (e.g., pubertal hormones), neural alterations, and environmental factors to the development of both healthy behavior and brain function as well as risk for poor mental and physical outcomes. This review outlines how the ABCD Study was designed to elucidate factors associated with the development of negative mental and physical health outcomes and will provide a selective overview of results emerging from the ABCD Study. Such emerging data includes initial validation of new instruments, important new information about the prevalence and correlates of mental health challenges in middle childhood, and promising data regarding neural correlates of both healthy and disordered behavior. In addition, we will discuss the challenges and opportunities to understanding both healthy development and the emergence of risk from ABCD Study data. Finally, we will overview the future directions of this large undertaking and the ways in which it will shape our understanding of the development of risk for poor mental and physical health outcomes.

Sex-dimorphic effects of biogenesis of lysosome-related organelles complex-1 deficiency on mouse perinatal brain development

The function(s) of the Biogenesis of Lysosome-related Organelles Complex-1 (BLOC-1) during brain development is to date largely unknown. Here, we investigated how its absence alters the trajectory of postnatal brain development using as model the pallid mouse. Most of the defects observed early postnatally in the mutant mice were more prominent in males than in females and in the hippocampus. Male mutant mice, but not females, had smaller brains as compared to sex-matching wild types at postnatal day 1 (P1), this deficit was largely recovered by P14 and P45. An abnormal cytoarchitecture of the pyramidal cell layer of the hippocampus was observed in P1 pallid male, but not female, or juvenile mice (P45), along with severely decreased expression levels of the radial glial marker Glutamate-Aspartate Transporter. Transcriptomic analyses showed that the overall response to the lack of functional BLOC-1 was more pronounced in hippocampi at P1 than at P45 or in the cerebral cortex. These observations suggest that absence of BLOC-1 renders males more susceptible to perinatal brain maldevelopment and although most abnormalities appear to have been resolved in juvenile animals, still permanent defects may be present, resulting in faulty neuronal circuits, and contribute to previously reported cognitive and behavioral phenotypes in adult BLOC-1-deficient mice.

Intrinsic neural circuitry of depression in adolescent females

BACKGROUND

Adolescence is characterized by affective and cognitive changes that increase vulnerability to depression, especially in females. Neurodevelopmental models attribute adolescent depression to abnormal responses in amygdala, striatum, and prefrontal cortex (PFC). We examined whether the strength of functional brain networks involving these regions predicts depression symptoms in adolescent females.

METHODS

In this longitudinal study, we recorded resting-state functional connectivity (RSFC) in 174 adolescent females. Using a cross-validation strategy, we related RSFC profiles that included (a) a network consisting of amygdala, striatum, and PFC (within-circuit model), (b) connectivity of this network to the whole brain (extended-circuit model), and (c) a network consisting of the entire brain (whole-brain model) to depression symptoms assessed concurrently and 18 months later.

RESULTS

In testing subsets, the within-circuit RSFC profiles were associated with depression symptoms concurrently and 18 months later, while the extended-circuit and whole-brain model did not explain any additional variance in depression symptoms. Connectivity related to anterior cingulate and ventromedial prefrontal cortex contributed most to the association.

CONCLUSIONS

Our results demonstrate that RSFC-based brain networks that include amygdala, striatum, and PFC are stable neural signatures of concurrent and future depression symptoms, representing a significant step toward identifying the neural mechanism of depression in adolescence.

Early Childhood Parenting Predicts Late Childhood Brain Functional Connectivity During Emotion Perception and Reward Processing

Seventy-nine 3-year olds and their mothers participated in a laboratory-based task to assess maternal hostility. Mothers also reported their behavioral regulation of their child. Seven years later, functional magnetic resonance imaging data were acquired while viewing emotional faces and completing a reward processing task. Maternal hostility predicted more negative amygdala connectivity during exposure to sad relative to neutral faces with frontal and parietal regions as well as more negative left ventral striatal connectivity during monetary gain relative to loss feedback with the right posterior orbital frontal cortex and right inferior frontal gyrus. In contrast, maternal regulation predicted enhanced cingulo-frontal connectivity during monetary gain relative to loss feedback. Results suggest parenting is associated with alterations in emotion and reward processing circuitry 7-8 years later.

Relationships between neural activation during a reward task and peripheral cytokine levels in youth with diverse psychiatric symptoms

BACKGROUND

Inflammation has been hypothesized to contribute to reward dysfunction across psychiatric conditions, but little is known about this relationship in youth. Therefore, the present study investigated the associations between general and specific markers of inflammation and neural activation during reward processing, including anticipation and attainment, in youth with diverse psychiatric symptoms.

METHODS

Forty-six psychotropic medication-free youth with diverse psychiatric symptoms underwent a blood draw to measure 41 cytokines, as well as structural and functional magnetic resonance imaging. The Reward Flanker Task examined neural activation during reward anticipation and attainment. Relationships between inflammation and neural activation were assessed using data reduction techniques across the whole-brain, as well as in specific reward regions of interest (basal ganglia, anterior and mid-cingulate cortex [ACC/MCC]).

RESULTS

Whole-brain principal component analyses showed that factor 3 (12 cytokines: FGF-2, Flt3-L, fractalkine, GM-CSF, IFN-α2, IFN-γ, IL-3, IL-4, IL-7, IL-17A, MDC, and VEGF) was negatively correlated with precuneus/posterior cingulate cortex activity during anticipation. Factor 2 (11 cytokines: eotaxin, IL-1α, IL-1Rα, IL-2, IL-5, IL-9, IL-12p40, IL-13, IL-15, MCP-3, and TNF-β) was negatively correlated with angular gyrus activity during attainment. ROI analyses additionally showed that multiple cytokines were related to activity in the basal ganglia (EGF, FGF-2, Flt-3L, IL-2, IL-13, IL-15, IL-1Rα, MCP-3) and ACC/MCC (Flt-3L) during attainment. C-reactive protein (CRP) was not associated with neural activation.

CONCLUSIONS

Investigation of specific markers of immune function showed associations between inflammatory processes and activation of posterior default mode network, prefrontal cortex, and basal ganglia regions during multiple phases of reward processing.

Abnormal development of early auditory processing in 22q11.2 Deletion Syndrome

The 22q11.2 Deletion Syndrome (22q11.2 DS) is one of the highest genetic risk factors for the development of schizophrenia spectrum disorders. In schizophrenia, reduced amplitude of the frequency mismatch negativity (fMMN) has been proposed as a promising neurophysiological marker for progressive brain pathology. In this longitudinal study in 22q11.2 DS, we investigate the progression of fMMN between childhood and adolescence, a vulnerable period for brain maturation. We measured evoked potentials to auditory oddball stimuli in the same sample of 16 patients with 22q11.2 DS and 14 age-matched controls in childhood and adolescence. In addition, we cross-sectionally compared an increased sample of 51 participants with 22q11.2 DS and 50 controls divided into two groups (8-14 and 14-20 years). The reported results are obtained using the fMMN difference waveforms. In the longitudinal design, the 22q11.2 deletion carriers exhibit a significant reduction in amplitude and a change in topographic patterns of the mismatch negativity response from childhood to adolescence. The same effect, reduced mismatch amplitude in adolescence, while preserved during childhood, is observed in the cross-sectional study. These results point towards functional changes within the brain network responsible for the fMMN. In addition, the adolescents with 22q11.2 DS displayed a significant increase in amplitude over central electrodes during the auditory N1 component. No such differences, reduced mismatch response nor increased N1, were observed in the typically developing group. These findings suggest different developmental trajectories of early auditory sensory processing in 22q11.2 DS and functional changes that emerge during the critical period of increased risk for schizophrenia spectrum disorders.

Potential Circadian Rhythms in Oligodendrocytes? Working Together Through Time

Oligodendrocytes (OL) are the only myelinating cells of the central nervous system thus interferences, either environmental or genetic, with their maturation or function have devastating consequences. Albeit so far neglected, one of the less appreciated, nevertheless possible, regulators of OL maturation and function is the circadian cycle. Yet, disruptions in these rhythms are unfortunately becoming a common "disorder" in the today's world. The temporal patterning of behaviour and physiology is controlled by a circadian timing system based in the anterior hypothalamus. At the molecular level, circadian rhythms are generated by a transcriptional/translational feedback system that regulates transcription and has a major impact on cellular function(s). Fundamental cellular properties/functions in most cell types vary with the daily circadian cycle: OL are unlikely an exception! To be clear, the presence of circadian oscillators or the cell-specific function(s) of the circadian clock in OL has yet to be defined. Furthermore, we wish to entertain the idea of links between the "thin" evidence on OL intrinsic circadian rhythms and their interjection(s) at different stages of lineage progression as well as in supporting/regulating OL crucial function: myelination. Individuals with intellectual and developmental syndromes as well as neurodegenerative diseases present with a disrupted sleep/wake cycle; hence, we raise the possibility that these disturbances in timing can contribute to the loss of white matter observed in these disorders. Preclinical and clinical work in this area is needed for a better understanding of how circadian rhythms influence OL maturation and function(s), to aid the development of new therapeutic strategies and standards of care for these patients.

Methylphenidate enhances neuronal differentiation and reduces proliferation concomitant to activation of Wnt signal transduction pathways

Methylphenidate (Ritalin) is the most commonly prescribed drug in the treatment of attention-deficit hyperactivity disorder. It is suggested that in vivo, methylphenidate treatment supports cortical maturation, however, the molecular and cellular mechanisms are not well understood. This study aimed to explore the potential effect of methylphenidate on cell proliferation and maturation in various cellular models, hypothesizing its interaction with the Wnt-signaling. The termination of cell proliferation concomitant to neuronal maturation following methylphenidate treatment was observed in all of the cell-models tested: murine neural stem-, rat PC12- and the human SH-SY5Y-cells. Inhibition of Wnt-signaling in SH-SY5Y cells with Dkk1 30 min before methylphenidate treatment suppressed neuronal differentiation but enhanced proliferation. The possible involvement of the dopamine-transporter in cell differentiation was discounted following the observation of opposing results after GBR-12909 treatment. Moreover, Wnt-activation via methylphenidate was confirmed in Wnt-luciferase-reporter assay. These findings reveal a new mechanism of action of methylphenidate that might explain long-term effects.

Anterior cingulate cortex γ-aminobutyric acid deficits in youth with depression

Abnormally low γ-aminobutyric acid (GABA) levels have been consistently reported in adults with major depressive disorder (MDD). Our group extended this finding to adolescents, and documented that GABA deficits were associated with anhedonia. Here we aimed to confirm our prior finding of decreased brain GABA in youth with depression and explore its associations with clinical variables. Forty-four psychotropic medication-free youth with MDD and 36 healthy control (HC) participants (12-21 years) were studied. Participants represent a combined sample of 39 newly recruited youth (MDD=24) and 41 youth from our previously reported study (MDD=20). GABA levels and the combined resonances of glutamate and glutamine (Glx) were measured in vivo in the anterior cingulate cortex using proton magnetic resonance spectroscopy. Youth with depression exhibited significantly lower GABA levels than HC in both the newly reported (P=0.003) and the combined (P=0.003) samples. When depressed participants were classified based on the presence of anhedonia, only the anhedonic MDD subgroup showed reduced GABA levels compared to HC (P=0.002). While there were no associations between any clinical measures and GABA or Glx levels in the new sample, GABA was negatively correlated with only anhedonia severity in the combined MDD group. Furthermore, in the combined sample, hierarchical regression models showed that anhedonia, but not depression severity, anxiety or suicidality, contributed significant variance in GABA levels. This report solidifies the evidence for a GABA deficit early in the course of MDD, which correlates specifically with anhedonia in the disorder.