Now we know

Abstract

Background

Elucidating the neurobiology of the adolescent brain is fundamental to our understanding of the etiology of psychiatric disorders such as schizophrenia and addiction, the symptoms of which often manifest during this developmental period. Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in adolescent behavioral and psychiatric vulnerabilities, but little is known about how adolescent VTA neurons encode information during motivated behavior.

Methods

We recorded daily from VTA neurons in adolescent and adult rats during learning and maintenance of a cued, reward-motivated instrumental task, and extinction from this task.

Results

During performance of the same motivated behavior, identical events were encoded differently by adult and adolescent VTA neurons. Adolescent VTA neurons with dopamine-like characteristics lacked a reward anticipation signal and showed a smaller response to reward delivery compared to adults. After extinction, however, these neurons maintained a strong phasic response to cues formerly predictive of reward opportunity.

Conclusions

Anticipatory neuronal activity in the VTA supports preparatory attention and is implicated in error prediction signaling. Absence of this activity, combined with persistent representations of previously rewarded experiences, may provide a mechanism for rash decision making in adolescents.

See: Yunbok Kim, Nicholas W Simon, Jesse Wood, Bita Moghaddam.  Reward anticipation is encoded differently by adolescent ventral tegmental area neurons.  Biological Psychiatry.  Publication stage: In Press Accepted Manuscript