The relationship between pubertal status and neural activity during risky decision-making in male adolescents

- Purpose: Adolescence is a time of dramatic changes in a range of behaviours, which occur in tandem with changes in brain structure and function. These coincide with the physiological changes of puberty, but little research has focussed on the possible contributing role of puberty. One important behaviour emerging in adolescence is the increased propensity to make risky decisions. A prominent theory to explain this increased propensity for risk is the ‘dual systems’ model (Casey et al., 2008), where risky decisions result from a dissociation in the timing of the maturation of the limbic system and the prefrontal cortex, both regions involved in risky decision-making. The limbic system (incorporating the ventral striatum) is hypothesised to mature relatively early in adolescence, and is thought to be related to pubertal maturation. In contrast, the prefrontal cortex is thought to undergo more protracted development throughout adolescence. This study explores how developmental changes in brain function when performing a risk-taking fMRI (functional Magnetic Resonance Imaging) task are related to puberty, independently of chronological age. - Methods: Forty-five male participants aged 13-14 years underwent fMRI scanning whilst performing a risk-taking task (BART task, adapted from Lejuez et al., 2002). In this age range, there is normal variability in pubertal development, with individuals being at all stages of puberty from pre-puberty to having completed puberty. In the BART task, participants had to decide whether to inflate a virtual balloon on a screen. Successful inflation of the balloon resulted in the opportunity to earn more money, but risked the balloon popping and the money being lost. Stopping allowed the participants to save the money towards their final earnings. Participants completed four six-minute runs of the task. Pubertal stage was assessed using self-report measures including a pictorial Tanner stage and the Pubertal Developmental Scale (Petersen et al., 1988). Salivary hormone levels were collected to measure levels of Testosterone, Oestradiol and DHEA. Participants also completed validated self-report questionnaires of risk-taking, impulsivity and sensation-seeking. - Results: The analysis focused on a main effect, across the entire group, of active decision-making compared to the control condition in regions including the prefrontal cortex and limbic system, which are known to be involved in risky decision-making. We also investigated whether this activation was differentially related to puberty across regions, using both group-wise and regression analyses. - Conclusions; This study investigated a role for puberty in the functional development of brain regions involved in risky decision-making in males, and further informs the usefulness of the dual systems model of risk taking during adolescence

Puberty and risky decision-making in male adolescents

Pubertal development is a potential trigger for increases in risk-taking behaviours during adolescence. Here, we sought to investigate the relationship between puberty and neural activation during risky decision-making in males using functional magnetic resonance imaging (fMRI). Forty-seven males aged 12.5-14.5 years completed an fMRI risk-taking task (BART) and reported their tendencies for risky decision-making using a self-report questionnaire. Puberty was assessed through self-reported pubertal status and salivary testosterone levels. Testosterone concentration, but not physical pubertal status, was positively correlated with self-reported risk-taking behaviour, while neither was correlated with BART performance. Across the whole sample, participants had greater activation of the bilateral nucleus accumbens and right caudate on trials when they made a successful risky decision compared to trials when they made a safe choice or when their risky decision was unsuccessful. There was a negative correlation between pubertal stage and brain activation during unsuccessful risky decision-making trials compared within unsuccessful control trials. Males at a lower stage of pubertal development showed increased activation in the left insula, right cingulate cortex, dorsomedial prefrontal cortex (dmPFC), right putamen and right orbitofrontal cortex (OFC) relative to more pubertally mature males during trials when they chose to take a risk and the balloon popped compared to when they watched the computer make an unsuccessful risky decision. Less pubertally mature males also showed greater activation in brain regions including the dmPFC, right temporal and frontal cortices, right OFC, right hippocampus and occipital cortex in unsuccessful risky trials compared to successful risky trials. These results suggest a puberty-related shift in neural activation within key brain regions when processing outcomes of risky decisions, which may reduce their sensitivity to negative feedback, and in turn contribute to increases in adolescent risk-taking behaviours

Is earlier obesity associated with poorer executive functioning later in childhood? Findings from the Millennium Cohort Study

BACKGROUND: Children affected with overweight or obesity have been associated with having lower educational achievement compared to peers who are non-overweight/obese. One of the drivers of this association could be a link between obesity and poorer executive function. Evidence is limited to small, cross-sectional studies which lack adjustment for important common causes. OBJECTIVE: We investigate the association between weight status and executive function longitudinally in mid-childhood, accounting for potential common causes. METHODS: Linear regression analyses were conducted to examine associations between weight status between 5 and 7 years and executive functioning at 11 years in members of the Millennium Cohort Study (n = 7739), accounting for a wide range of potential common causes. Age- and sex-specific International Obesity Taskforce cut-points for body mass index (BMI) were used. Executive function, including decision-making, impulsivity and spatial working memory, was assessed using the Cambridge Neuropsychological Test Automated Battery. RESULTS: There were no unadjusted associations between weight status and decision-making or impulsivity. After adjustment for all potential common causes, there was a lack of consistent evidence to support an association between persistent obesity (including overweight) between 5 and 7 years and spatial working memory task at 11 years. CONCLUSIONS: We found little evidence that poorer spatial working memory contributes to the association of children with obesity having lower educational achievement

Growth and adrenarche: findings from the CATS observational study

BACKGROUND: There is increasing evidence that patterns of pubertal maturation are associated with different patterns of health risk. This study aimed to explore the associations between anthropometric measures and salivary androgen concentrations in pre-adolescent children. METHODS: We analysed a stratified random sample (N=1151) of pupils aged 8-9 years old from 43 primary schools in Melbourne, Australia from the Childhood to Adolescence Transition Study. Saliva samples were assayed for dehydroepiandrosterone (DHEA), DHEA-sulfate and testosterone. Anthropometric measures included height, weight, body mass index (BMI) and waist circumference. Associations between (1) anthropometric measures and each androgen, and (2) hormone status with obesity and parental report of pubertal development were investigated using linear regression modelling with general estimating equations. RESULTS: Greater height, weight, BMI and waist circumference were positively associated with higher androgen concentrations, after adjusting for sex and socioeconomic status. Being overweight or obese was associated with higher testosterone and DHEA concentrations compared with the normal BMI category. Those who were obese were more likely (OR=2.7, 95% CI 1.61 to 4.43, p<0.001) to be in the top tertile of age-adjusted androgen status in both sexes. CONCLUSION: This study provides clear evidence for an association between obesity and higher androgen levels in mid-childhood. The adrenal transition may be a critical time period for weight management intervention strategies in order to manage the risk for metabolic problems in later life for high-risk individuals

Diffusion MRI of white matter microstructure development in childhood and adolescence: Methods, challenges and progress

Diffusion magnetic resonance imaging (dMRI) continues to grow in popularity as a useful neuroimaging method to study brain development, and longitudinal studies that track the same individuals over time are emerging. Over the last decade, seminal work using dMRI has provided new insights into the development of brain white matter (WM) microstructure, connections and networks throughout childhood and adolescence. This review provides an introduction to dMRI, both diffusion tensor imaging (DTI) and other dMRI models, as well as common acquisition and analysis approaches. We highlight the difficulties associated with ascribing these imaging measurements and their changes over time to specific underlying cellular and molecular events. We also discuss selected methodological challenges that are of particular relevance for studies of development, including critical choices related to image acquisition, image analysis, quality control assessment, and the within-subject and longitudinal reliability of dMRI measurements. Next, we review the exciting progress in the characterization and understanding of brain development that has resulted from dMRI studies in childhood and adolescence, including brief overviews and discussions of studies focusing on sex and individual differences. Finally, we outline future directions that will be beneficial to the field

Puberty and risky decision-making in male adolescents

Pubertal development is a potential trigger for increases in risk-taking behaviours during adolescence. Here, we sought to investigate the relationship between puberty and neural activation during risky decision-making in males using functional magnetic resonance imaging (fMRI). Forty-seven males aged 12.5–14.5 years completed an fMRI risk-taking task (BART) and reported their tendencies for risky decision-making using a self-report questionnaire. Puberty was assessed through self-reported pubertal status and salivary testosterone levels. Testosterone concentration, but not physical pubertal status, was positively correlated with self-reported risk-taking behaviour, while neither was correlated with BART performance. Across the whole sample, participants had greater activation of the bilateral nucleus accumbens and right caudate on trials when they made a successful risky decision compared to trials when they made a safe choice or when their risky decision was unsuccessful. There was a negative correlation between pubertal stage and brain activation during unsuccessful risky decision-making trials compared within unsuccessful control trials. Males at a lower stage of pubertal development showed increased activation in the left insula, right cingulate cortex, dorsomedial prefrontal cortex (dmPFC), right putamen and right orbitofrontal cortex (OFC) relative to more pubertally mature males during trials when they chose to take a risk and the balloon popped compared to when they watched the computer make an unsuccessful risky decision. Less pubertally mature males also showed greater activation in brain regions including the dmPFC, right temporal and frontal cortices, right OFC, right hippocampus and occipital cortex in unsuccessful risky trials compared to successful risky trials. These results suggest a puberty-related shift in neural activation within key brain regions when processing outcomes of risky decisions, which may reduce their sensitivity to negative feedback, and in turn contribute to increases in adolescent risk-taking behaviours

Roles of cyberbullying, sleep, and physical activity in mediating the effects of social media use on mental health and wellbeing among young people in England: a secondary analysis of longitudinal data

BACKGROUND: There is growing concern about the potential associations between social media use and mental health and wellbeing in young people. We explored associations between the frequency of social media use and later mental health and wellbeing in adolescents, and how these effects might be mediated. METHODS: We did secondary analyses of publicly available data from the Our Futures study, a nationally representative, longitudinal study of 12 866 young people from age 13 years to 16 years in England. The exposure considered was the frequency of social media use (from weekly or less to very frequent [multiple times daily]) at wave 1 (participants aged 13-14 years) through wave 3 of the study (participants aged 15-16 years). Outcomes were mental health at wave 2 (with high 12-item General Health Questionnaire [GHQ12] scores [≥3] indicating psychological distress), and wellbeing at wave 3 (life satisfaction, feeling life is worthwhile, happiness, and anxiety, rated from 1 to 10 by participants). Analyses were adjusted for a minimal sufficient confounding structure, and were done separately for boys and girls. Cyberbullying, sleep adequacy, and physical activity were assessed as potential mediators of the effects. FINDINGS: Very frequent use of social media increased from wave 1 to wave 3: from 34·4% (95% CI 32·4-36·4) to 61·9% (60·3-63·6) in boys, and 51·4% (49·5-53·3) to 75·4% (73·8-76·9) in girls. Very frequent social media use in wave 1 predicted a high GHQ12 score at wave 2 among girls (adjusted odds ratio [OR] 1·31 [95% CI 1·06-1·63], p=0·014; N=4429) and boys (1·67 [1·24-2·26], p=0·0009; N=4379). Persistent very frequent social media use across waves 1 and 2 predicted lower wellbeing among girls only (adjusted ORs 0·86 [0·74-0·99], N=3753, p=0·039 for life satisfaction; 0·80 [0·70-0·92], N=3831, p=0·0013 for happiness; 1·28 [1·11-1·48], N=3745, p=0·0007 for anxiety). Adjustment for cyberbullying, sleep, and physical activity attenuated the associations of social media use with GHQ12 high score (proportion mediated 58·2%), life satisfaction (80·1%), happiness (47·7%), and anxiety (32·4%) in girls, such that these associations (except for anxiety) were no longer significant; however, the association with GHQ12 high score among boys remained significant, being mediated only 12·1% by these factors. INTERPRETATION: Mental health harms related to very frequent social media use in girls might be due to a combination of exposure to cyberbullying or displacement of sleep or physical activity, whereas other mechanisms appear to be operative in boys. Interventions to promote mental health should include efforts to prevent or increase resilience to cyberbullying and ensure adequate sleep and physical activity in young people. FUNDING: None

Supplementary Material for: The Developmental Mismatch in Structural Brain Maturation during Adolescence

Regions of the human brain develop at different rates across the first two decades of life, with some maturing before others. It has been hypothesized that a mismatch in the timing of maturation between subcortical regions (involved in affect and reward processing) and prefrontal regions (involved in cognitive control) underlies the increase in risk-taking and sensation-seeking behaviors observed during adolescence. Most support for this ‘dual systems' hypothesis relies on cross-sectional data, and it is not known whether this pattern is present at an individual level. The current study utilizes longitudinal structural magnetic resonance imaging (MRI) data to describe the developmental trajectories of regions associated with risk-taking and sensation-seeking behaviors, namely, the amygdala, nucleus accumbens (NAcc) and prefrontal cortex (PFC). Structural trajectories of gray matter volumes were analyzed using FreeSurfer in 33 participants aged 7-30 years, each of whom had at least three high-quality MRI scans spanning three developmental periods: late childhood, adolescence and early adulthood (total 152 scans). The majority of individuals in our sample showed relatively earlier maturation in the amygdala and/or NAcc compared to the PFC, providing evidence for a mismatch in the timing of structural maturation between these structures. We then related individual developmental trajectories to retrospectively assessed self-reported risk-taking and sensation-seeking behaviors during adolescence in a subsample of 24 participants. Analysis of this smaller sample failed to find a relationship between the presence of a mismatch in brain maturation and risk-taking and sensation-seeking behaviors during adolescence. Taken together, it appears that the developmental mismatch in structural brain maturation is present in neurotypically developing individuals. This pattern of development did not directly relate to self-reported behaviors at an individual level in our sample, highlighting the need for prospective studies combining anatomical and behavioral measures