Marieke G.N. Bos

Longitudinal development of hippocampal subregions from childhood to adulthood

Highlights • Hippocampal subregions develop in differential ways from childhood to adulthood.• Subiculum, CA1, ML and fimbria showed nonlinear trajectories with initial increases.• Parasubiculum, presubiculum, CA2/3, CA4 and GC-DG showed linear volume decreases.• There were no sex differences in hippocampal subregion development.• General cognitive ability associated with CA2/3 and CA4 volumes and ML development.

Exploring the role of testosterone in the cerebellum link to neuroticism: From adolescence to early adulthood

Previous research has found an association between a smaller cerebellar volume and higher levels of neuroticism. The steroid hormone testosterone reduces stress responses and the susceptibility to negative mood. Together with in vitro studies showing a positive effect of testosterone on cerebellar gray matter volumes, we set out to explore the role of testosterone in the relation between cerebellar gray matter and neuroticism. Structural magnetic resonance imaging scans were acquired, and indices of neurotic personality traits were assessed by administering the depression and anxiety scale of the revised NEO personality inventory and Grays behavioural avoidance in one hundred and forty-nine healthy volunteers between 12 and 27 years of age. Results demonstrated an inverse relation between total brain corrected cerebellar volumes and neurotic personality traits in adolescents and young adults. In males, higher endogenous testosterone levels were associated with lower scores on neurotic personality traits and larger cerebellar gray matter volumes. No such relations were observed in the female participants. Analyses showed that testosterone significantly mediated the relation between male cerebellar gray matter and measures of neuroticism. Our findings on the interrelations between endogenous testosterone, neuroticism and cerebellar morphology provide a cerebellum-oriented framework for the susceptibility to experience negative emotions and mood in adolescence and early adulthood.

Emerging depression in adolescence coincides with accelerated frontal cortical thinning

Background Adolescence is a transition period characterized by heightened emotional reactivity, which for some sets the stage for emerging depressive symptoms. Prior studies suggest that adolescent depression is associated with deviant cortical and subcortical brain structure. Longitudinal studies are, however, currently scarce, but critical to detect which adolescents are at risk for developing depressive symptoms. Methods In this longitudinal study, a community sample of 205 participants underwent magnetic resonance imaging (MRI) in three biennial waves (522 scans) spanning 5 years across ages 8–25 years. Depressive symptomatology was assessed using self‐report at the third time point. Mixed models were used to examine the relations between structural brain development, specifically regional change in cortical thickness, surface area and subcortical volumes (hippocampus and amygdala), and depressive symptoms. Results Accelerated frontal lobe cortical thinning was observed in adolescents who developed depressive symptoms at the third time point. This effect remained after controlling for parent‐reported affective problems at the first time point. Moreover, the effect was driven by specific lateral orbitofrontal and precentral regions. In addition, differential developmental trajectories of parietal cortical thickness and surface area in several regions were found for participants reporting higher depressive symptomatology, but these results did not survive correction for multiple comparisons. Volumes or developmental volume changes in hippocampus or amygdala were not related to depressive symptoms. Conclusions This study showed that emerging depression is associated with cortical thinning in frontal regions within individuals. These findings move beyond detecting cross‐sectional correlations and set the stage for early detection, which may inform future intervention.

Unraveling age, puberty and testosterone effects on subcortical brain development across adolescence

The onset of adolescence in humans is marked by hormonal changes that give rise to secondary sexual characteristics, noted as puberty. It has, however, proven challenging to unravel to what extent pubertal changes may have organizing effects on the brain beyond chronological age, as reported in animal studies. The present longitudinal study aimed to characterize the unique effects of age and puberty on subcortical brain volumes and included three waves of data collection at two-year intervals and 680 T1-weighted MRI scans of 271 participants (54% females) aged between 8 and 29 years old. Generalized additive mixed model procedures were used to assess the effects of age, self-report pubertal status and testosterone level on basal ganglia, thalamus, hippocampus, amygdala and cerebellum gray matter volumes. We observed age-related increases in putamen and pallidum volumes, and decreases in accumbens and thalamus volumes, all show larger volumes in boys than girls. Only the cerebellum showed an interaction effect of age by sex, such that males showed prolonged increases in cerebellar volume than females. Next, we showed that changes in self-report puberty status better described developmental change than chronological age for most structures in males, and for caudate, pallidum and hippocampal volumes in females. Furthermore, changes in testosterone level were related to development of pallidum, accumbens, hippocampus and amygdala volumes in males and caudate and hippocampal volumes in females. The modeling approach of the present study allowed us to characterize the complex interactions between chronological age and pubertal maturational changes, and the findings indicate puberty unique changes in brain structure that are sex specific.

Longitudinal Associations between Bullying and Emotions in Deaf and Hard of Hearing Adolescents.

In hearing adolescents, emotions play important roles in the development of bullying and victimization. Yet, it is unclear whether this also applies to adolescents who are deaf or hard of hearing (DHH). The present study examines the longitudinal associations of anger, fear, guilt, and shame with bullying/victimization in DHH adolescents. Overall, 80 DHH and 227 hearing adolescents (Mage = 11.7; 103 males) completed self-reports on two occasions with a 9-month interval. Outcomes show that DHH adolescents reported fewer bullying behaviors, but more victimization compared to hearing adolescents. Longitudinal relations between emotions and bullying/victimization did not differ between DHH and hearing adolescents. More anger and less guilt predicted increased bullying, and more bullying predicted increased anger and decreased guilt. Higher levels of anger, fear, and shame predicted increased victimization, and more victimization predicted increased anger, fear, and shame. These findings emphasize that emotions are involved in both the emergence and maintenance of bullying and victimization. These outcomes have clinical implications for the prevention of bullying.

Longitudinal structural brain development and externalizing behavior in adolescence

Background Cross‐sectional studies report relations between externalizing behavior and structural abnormalities in cortical thickness of prefrontal regions and volume reductions in subcortical regions. To understand how these associations emerge and develop, longitudinal designs are pivotal. Method In the current longitudinal study, a community sample of children, adolescents and young adults (N = 271) underwent magnetic resonance imaging (MRI) in three biennial waves (680 scans). At each wave, aspects of externalizing behavior were assessed with parent‐reported aggression and rule‐breaking scores (Child Behavior Checklist), and self‐reported aggression scores (Buss‐Perry Aggression Questionnaire). Regions of interest (ROIs) were selected based on prior research: dorsolateral prefrontal (dlPFC), orbitofrontal (OFC), anterior cingulate cortex (ACC), insula, and parahippocampal cortex, as well as subcortical regions. Linear mixed models were used to assess the longitudinal relation between externalizing behavior and structural brain development. Structural covariance analyses were employed to identify whether longitudinal relations between ROIs (maturational coupling) were associated with externalizing behavior. Results Linear mixed model analyses showed a negative relation between parent‐reported aggression and right hippocampal volume. Moreover, this longitudinal relation was driven by change in hippocampal volume and not initial volume of hippocampus at time point 1. Exploratory analyses showed that stronger maturational coupling between prefrontal regions, the limbic system, and striatum was associated with both low and high externalizing behavior. Conclusions Together, these findings reinforce the hypothesis that altered structural brain development coincides with development of more externalizing behavior. These findings may guide future research on normative and deviant development of externalizing behavior.