Development of Multifaceted Risk Taking and the Relations to Sex Steroid Hormones: A Longitudinal Study

Risk taking is a multidimensional construct. It is currently unclear which aspects of risk‐taking change most during adolescence and if/how sex hormones contribute to risk‐taking tendencies. This study applied a longitudinal design with three time‐points, separated by 2 years, in participants aged 8–29 years (670 observations). The Balloon Analogue Risk Task, a delay discounting task, and various self‐report questionnaires were administered, to measure aspects of risk taking. Longitudinal analyses demonstrated mostly nonlinear age‐related patterns in risk‐taking behavior and approach‐related personality characteristics (peaking in late adolescence). Increased testosterone and estradiol were found to increase risk‐taking behavior and impulsive personality, but decrease avoidance‐like personality. This study demonstrates that risk taking is most pronounced in mid‐to‐late adolescence and suggests that sex hormones accelerate this maturational process.Article / Letter to editorInstituut PsychologieInstituut Pedagogische Wetenschappe

Het hoorrecht van de procespositie van minderjarigen in familie- en jeugdzaken geëvalueerd

Coherent privaatrechtPathways through Adolescenc

Reward-related neural responses are dependent on the beneficiary

Prior studies have suggested that positive social interactions are experienced as rewarding. Yet, it is not well understood how social relationships influence neural responses to other persons gains. In this study, we investigated neural responses during a gambling task in which healthy participants (N¼31; 18 females) could win or lose money for themselves, their best friend or a disliked other (antagonist). At the moment of receiving outcome, person-related activity was observed in the dorsal medial prefrontal cortex (dmPFC), precuneus and temporal parietal junction (TPJ), showing higher activity for friends and antagonists than for self, and this activity was independent of outcome. The only region showing an interaction between the person-participants played for and outcome was the ventral striatum. Specifically, the striatum was more active following gains than losses for self and friends, whereas for the antagonist this pattern was reversed. Together, these results show that, in a context with social and reward information, social aspects are processed in brain regions associated with social cognition (mPFC, TPJ), and reward aspects are processed in primary reward areas (striatum). Furthermore, there is an interaction of social and reward information in the striatum, such that reward-related activity was dependent on social relationship.Pathways through Adolescenc

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.Pathways through Adolescenc

A multisample study of longitudinal changes in brain network architecture in 4-13-year-old children

Pathways through Adolescenc

The early puberal brain: Work in progress. A study on genetic and hormonal influences

The timing and speed of developmental processes during healthy puberty might be of critical importance to optimal adult functioning. Indeed, diseases that affect the brain at a young age, such as schizophrenia, are likely to have their origin in this period. The general aim of this thesis was to explore possible mechanisms contributing to individual variation in brain structure at the brink of puberty. Two lines of research were conducted: (1) The relative importance of genetic and environmental influences on global and regional brain volume (2) The association between hypothalamus-pituitary-gonadal (HPG)-axis hormones and brain structure. Research was based on a sample of 107 twin-families consisting of 9-year-old healthy twin pairs (45 monozygotic (MZ) and 62 dizygotic (DZ) pairs) and one of their full siblings (N=85) between 10 and 15 years of age. Results showed that in 9-year-olds, global brain volumes are already remarkably heritable, with estimates ranging from 77% (i.e., gray matter) to 94% (i.e., total brain volume). Regionally, white matter density in posterior parts of the fronto-occipital and superior longitudinal fascicles, cingulum and corpus callosum were found to be significantly heritable with estimates ranging up to 93%. Interestingly, the areas within gray matter density that were significantly heritable were substantially smaller, and included the amygdala and temporal lobes. The onset of secondary sexual characteristics (SSC) of puberty was associated with decreased frontal and parietal gray matter densities and was mainly found in girls. Nocturnal rises in luteinizing hormone (LH) levels from the pituitary mark the beginning of puberty in both boys and girls, even before SSC of puberty are visible. An increased production of LH was associated with larger global and focal white matter. This association was driven by a common genetic factor. LH-levels were however not related to global or regional gray matter. The pubertal brain might respond differentially to changing hormone levels over time, therefore the possible association between sex steroids testosterone and estradiol and brain structure was studied in a more advanced stage of puberty. Indeed in girls, a higher level of estradiol was mainly associated with decreased gray matter within the prefrontal, parietal and temporal cortices (not with white matter). At this age, testosterone levels were not associated with gray or white matter. Sex differences in brain structure were not related to sex steroid levels. The last study of this thesis describes the possible influence of the intrauterine presence of a male co-twin on masculinization of brain volume, possibly mediated by higher prenatal testosterone exposure. Results showed that, corrected for larger global brain volumes in boys, children with a male-co twin showed a larger total brain and cerebellar volume versus children with a female-co-twin. It might be suggested that prenatal testosterone plays a role in development of sex differences in the human brain. This thesis contains the first series of studies that has provided important new leads into the complex interplay between genetic and environmental factors, hormones and brain structure in this critical period of life

The influence of sex steroids on structural brain maturation in adolescence

Puberty reflects a period of hormonal changes, physical maturation and structural brain reorganization. However, little attention has been paid to what extent sex steroids and pituitary hormones are associated with the refinement of brain maturation across adolescent development. Here we used high-resolution structural MRI scans from 215 typically developing individuals between ages 8-25, to examine the association between cortical thickness, surface area and (sub)cortical brain volumes with luteinizing hormone, testosterone and estradiol, and pubertal stage based on self-reports. Our results indicate sex-specific differences in testosterone related influences on gray matter volumes of the anterior cingulate cortex after controlling for age effects. No significant associations between subcortical structures and sex hormones were found. Pubertal stage was not a stronger predictor than chronological age for brain anatomical differences. Our findings indicate that sex steroids are associated with cerebral gray matter morphology in a sex specific manner. These hormonal and morphological differences may explain in part differences in brain development between boys and girls

Development of risk-taking: contributions from adolescent testosterone and the orbito-frontal cortex

The role of puberty in the development of risk taking remains poorly understood. Here, in a normative sample of 268 participants between 8 and 25 years old, we applied a psycho-endocrine neuroimaging approach to investigate the contribution of testosterone levels and OFC morphology to individual differences in risk taking. Risk taking was measured with the balloon analogue risk-taking task. We found that, corrected for age, higher endogenous testosterone level was related to increased risk taking in boys (more explosions) and girls (more money earned). In addition, a smaller medial OFC volume in boys and larger OFC surface area in girls related to more risk taking. A mediation analysis indicated that OFC morphology partly mediates the association between testosterone level and risk taking, independent of age. Mediation was found in such a way that a smaller medial OFC in boys potentiates the association between testosterone and risk taking but suppresses the association in girls. This study provides insights into endocrinological and neural underpinnings of normative development of risk taking, by indicating that OFC morphology, at least partly, mediates the association between testosterone and risk-taking behavior