The social brain undergoes developmental change during adolescence, and pubertal hormones are hypothesized to contribute to this development. We used fMRI to explore how pubertal indicators (salivary concentrations of testosterone, oestradiol and DHEA; pubertal stage; menarcheal status) relate to brain activity during a social emotion task. Forty-two females aged 11.1 to 13.7 years underwent fMRI scanning while reading scenarios pertaining either to social emotions, which require the representation of another person's mental states, or to basic emotions, which do not. Pubertal stage and menarcheal status were used to assign girls to early or late puberty groups. Across the entire sample, the contrast between social versus basic emotion resulted in activity within the social brain network, including dorsomedial prefrontal cortex (DMPFC), the posterior superior temporal sulcus, and the anterior temporal cortex (ATC) in both hemispheres. Increased hormone levels (independent of age) were associated with higher left ATC activity during social emotion processing. More advanced age (independent of hormone levels) was associated with lower DMPFC activity during social emotion processing. Our results suggest functionally dissociable effects of pubertal hormones and age on the adolescent social brain.

During adolescence, risk-taking emerges as an important behaviour. One prominent theory proposes that this increased risk-taking results from a dissociation in the maturational timing of the brain regions involved in reward processing and cognitive control. It is hypothesised that the regions involved in reward processing, particularly the limbic system, mature relatively early in adolescence, in tandem with pubertal maturation. In contrast, the cognitive control regions of the brain, found principally within the prefrontal cortex, are proposed to undergo protracted development throughout adolescence. The goal of this functional Magnetic Resonance Imaging (fMRI) study was to explore how developmental changes in brain function when performing a risk-taking task were related to puberty, independently of chronological age. Fifty male participants aged 12–14 years underwent fMRI scanning whilst performing a risk-taking task (the BART task). Indicators of pubertal development were collected, including self-reported pubertal status using Tanner stage diagrams and salivary hormone levels for testosterone, oestradiol and dehydroepiandrosterone (DHEA). Participants were grouped by pubertal status into early-mid puberty (≤Tanner Stage 3 in pubic hair and gonadal development; n = 23) and late-post puberty (≥Tanner Stage 4 in either pubic hair or gonadal development; n = 26). General linear modelling was used to investigate whether there were differences in neural activity within the reward processing and cognitive control brain networks during the risk-taking task with pubertal development, as measured by Tanner stage puberty groups and hormonal levels. Oestradiol levels were positively correlated with neural activity in the medial prefrontal cortex and orbitofrontal cortex when deciding not to make a risky choice. Testosterone levels and puberty grouping (early-mid vs. late-post) were correlated with prefrontal cortex activation during the processing of outcomes of a risky decision. This study highlights the complexity of the decision-making process, and the extensive network of brain regions involved. It suggests that various aspects of the process of deciding to make a risky decision are related to distinct elements of pubertal development.

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