A neurodevelopmental shift in reward circuitry from mother’s to nonfamilial voices in adolescence

Abstract

The social world of young children primarily revolves around parents and caregivers, who play a key role in guiding children’s social and cognitive development. However, a hallmark of adolescence is a shift in orientation towards nonfamilial social targets, an adaptive process that prepares adolescents for their independence. Little is known regarding neurobiological signatures underlying changes in adolescents’ social orientation. Using functional brain imaging of human voice processing in children and adolescents (ages 7-16), we demonstrate distinct neural signatures for mother’s voice and nonfamilial voices across child and adolescent development in reward and social valuation systems, instantiated in nucleus accumbens and ventromedial prefrontal cortex. While younger children showed increased activity in these brain systems for mother’s voice compared to nonfamilial voices, older adolescents showed the opposite effect with increased activity for nonfamilial compared to mother’s voice. Findings uncover a critical role for reward and social valuative brain systems in the pronounced changes in adolescents’ orientation towards nonfamilial social targets. Our approach provides a template for examining developmental shifts in social reward and motivation in individuals with pronounced social impairments, including adolescents with autism.

Significance Statement:

Children’s social worlds undergo a transformation during adolescence. While socialization in young children revolves around parents and caregivers, adolescence is characterized by a shift in social orientation towards nonfamilial social partners. Here we show that this shift is reflected in neural activity measured from reward processing regions in response to brief vocal samples. When younger children hear their mother’s voice, reward processing regions show greater activity compared to when they hear nonfamilial, unfamiliar voices. Strikingly, older adolescents show the opposite effect, with increased activity for nonfamilial compared to mother’s voice. Findings identify the brain basis of adolescents’ switch in social orientation towards nonfamilial social partners and provides a template for understanding neurodevelopment in clinical populations with social and communication difficulties.