Testosterone levels correspond with increased ventral striatum activation in response to monetary rewards in adolescents

Abstract

Risk taking is an integral part of learning and development, particularly during adolescence the prevalence of risky behaviors peak. It is hypothesized that the tendency to take risks is related to pubertal maturation, where there is interplay between gonadal hormones, the neural mechanisms that underlie affective (e.g., reward) processing, and risky behavior. To test this hypothesis, fifty healthy adolescents (aged 10-16 years; 33 girls, 17 boys) at different stages of puberty performed a gambling task while lying in the MRI scanner, and provided saliva samples for hormone assessment. Gonadal hormone levels were correlated with the neural response to receiving a monetary reward. Results showed that testosterone level correlated positively with activation in the striatum for both boys and girls, suggesting that individual differences in hormones at puberty are related to the way adolescents respond to reward, which can ultimately affect risk-taking behavior.

Fig. 1

The Jackpot gambling task. Example of a high-risk trial in which the participant chooses to spin (by a right button press) and wins (i.e., receives a monetary reward).

Fig. 2

Risk-taking behavior. Percentage of “spinning” trials in both low-risk (LR) and high-risk (HR) conditions, plotted for boys and girls separately.

Fig. 3

Whole-brain results for the contrast reward > loss. (A) Regions of activation for all participants included the dorsal and ventral striatum, and the medial orbitofrontal cortex. (B) Regions of activation for boys and girls separately included the bilateral striatum in both groups.

Fig. 4

Results for the regression analyses with gonadal hormones. (A) Regions of activation for reward > loss with testosterone as predictor included the bilateral ventral striatum in boys (left), and left ventral striatum in girls (right), at a threshold of p < .005. (B) Regions of activation for reward > loss with estradiol as predictor included dorsal striatum, DLPFC, and medial PFC in girls only, at a threshold of p < .005.

Fig. 5

Results of sphere ROIs (radius 6 mm) based on the peak voxel of reward-related activation that correlates positively with testosterone level for boys in (A) left putamen, for girls in (B) left caudate, and for boys and girls (i.e., overlap in activation) in (C) left putamen.