Neurobiology of the development of motivated behaviors in adolescence: A window into a neural systems model

Adaptive motivated behaviors are at the core of a successful life. Conversely, perturbed motivated behaviors are the hallmark of psychiatric disorders. Based on the notion that most psychopathology is developmental in nature, understanding the neural mechanisms that control motivated behavior across development and in psychopathology is a critical step for preventing and treating psychiatric diseases. This review focuses on adolescence, which is the critical developmental period that determines the successful passage into adulthood. We first present a heuristic neural systems model of motivated behavior (triadic model) that integrates neuroscience theories and the emerging body of functional neuroimaging work on the neurodevelopment of motivated behavior. As a key feature of adolescence, social reorientation is particularly emphasized through the presentation of a parallel model of social integration processing network. Although not yet integrated in the triadic model, pubertal changes and their possible contribution to adolescent motivated behavior are reviewed. Similarly, given its central role in motivated actions, the dopamine system is discussed from the perspective of animal studies dedicated to changes of this system across adolescence. This review reveals vast gaps in knowledge about the neurobiology of motivated behavior in normally developing individuals, which makes the translation to psychopathology only tentative. However, it provides clear directions for future research.