Triadic model of the neurobiology of motivated behavior in adolescence.
BACKGROUND
Risk-taking behavior is a major cause of morbidity and mortality in adolescence. In the context of decision theory and motivated (goal-directed) behavior, risk-taking reflects a pattern of decision-making that favors the selection of courses of action with uncertain and possibly harmful consequences. We present a triadic, neuroscience systems-based model of adolescent decision-making.


METHODS
We review the functional role and neurodevelopmental findings of three key structures in the control of motivated behavior, i.e. amygdala, nucleus accumbens, and medial/ventral prefrontal cortex. We adopt a cognitive neuroscience approach to motivated behavior that uses a temporal fragmentation of a generic motivated action. Predictions about the relative contributions of the triadic nodes to the three stages of a motivated action during adolescence are proposed.


RESULTS
The propensity during adolescence for reward/novelty seeking in the face of uncertainty or potential harm might be explained by a strong reward system (nucleus accumbens), a weak harm-avoidant system (amygdala), and/or an inefficient supervisory system (medial/ventral prefrontal cortex). Perturbations in these systems may contribute to the expression of psychopathology, illustrated here with depression and anxiety.


CONCLUSIONS
A triadic model, integrated in a temporally organized map of motivated behavior, can provide a helpful framework that suggests specific hypotheses of neural bases of typical and atypical adolescent behavior.
Ernst
Monique
M
Section of Developmental and Affective Neuroscience, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA. ernstm@mail.nih.gov
Pine
Daniel S
DS
Hardin
Michael
M
D000293:Adolescent; D000679:Amygdala / Q000502:physiology; D001921:Brain / Q000502:physiology*; D003657:Decision Making; D003863:Depression / Q000523:psychology; D006801:Humans; D009042:Motivation; D009714:Nucleus Accumbens / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology