As we have learned more about the specific brain and behavioral changes of adolescence several neurobehavioral models have been proposed. Central to most of these is the notion that immature neuronal processing in the prefrontal cortex and other cortical and subcortical regions, along with their interaction, leads to behavior that is biased towards risk, reward, and emotional reactivity during the adolescent period. Recent work on the development of inhibitory interneuron circuits and their changing interaction with neuromodulatory systems during adolescence may also shed light on why illnesses like schizophrenia typically manifest at this time. Using techniques like fMRI in humans and electrophysiological recordings in laboratory animals, we are beginning to identify more precisely how adolescents process reward and other aspects of motivated behavior differently from adults. Doing so is a critical step toward ascertaining the brain-based vulnerabilities of normal adolescent behavior and in understanding the pathophysiology of the psychiatric illnesses that develop during this period.
