Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, F-33400 Talence, France.
J Neurosci. 2012 Nov 14;32(46):16223-32. doi: 10.1523/JNEUROSCI.3080-12.2012.
Adolescence is a crucial developmental period characterized by specific behaviors reflecting the immaturity of decision-making abilities. However, the maturation of precise cognitive processes and their neurobiological correlates at this period remain poorly understood. Here, we investigate whether a differential developmental time course of dopamine (DA) pathways during late adolescence could explain the emergence of particular executive and motivational components of goal-directed behavior. First, using a contingency degradation protocol, we demonstrate that adolescent rats display a specific deficit when the causal relationship between their actions and their consequences is changed. When the rats become adults, this deficit disappears. In contrast, actions of adolescents remain sensitive to outcome devaluation or to the influence of a pavlovian-conditioned stimulus. This aspect of cognitive maturation parallels a delayed development of the DA system, especially the mesocortical pathway involved in action adaptation to rule changes. Unlike in striatal and nucleus accumbens regions, DA fibers and DA tissue content continue to increase in the medial prefrontal cortex from juvenile to adult age. Moreover, a sustained overexpression of DA receptors is observed in the prefrontal region until the end of adolescence. These findings highlight the relationship between the emergence of specific cognitive processes, in particular the adaptation to changes in action consequences, and the delayed maturation of the mesocortical DA pathway. Similar developmental processes in humans could contribute to the adolescent vulnerability to the emergence of several psychiatric disorders characterized by decision-making deficits.
青春期是一个关键的发展阶段，其特征是反映决策能力不成熟的特定行为。然而，在此期间，精确认知过程及其神经生物学相关性的成熟仍知之甚少。在这里，我们研究了在青春期晚期多巴胺（DA）途径的不同发育时间过程是否可以解释目标导向行为的特定执行和动机成分的出现。首先，我们使用条件性消退协议表明，青少年大鼠在其行为与其后果之间的因果关系发生变化时会表现出特定的缺陷。当大鼠成年后，这种缺陷就会消失。相比之下，青少年的行为仍然对结果的贬值或条件反射性刺激的影响敏感。这种认知成熟的方面与 DA 系统的延迟发育相平行，特别是涉及到适应规则变化的行为的中脑皮质途径。与纹状体和伏隔核区域不同，从中年到成年，DA 纤维和 DA 组织含量在大脑前额叶皮层中继续增加。此外，在青春期结束之前，在大脑前额叶区域持续观察到 DA 受体的过度表达。这些发现强调了特定认知过程的出现之间的关系，特别是对行为后果变化的适应，以及中脑皮质 DA 途径的延迟成熟。人类中类似的发育过程可能导致青少年易患几种以决策缺陷为特征的精神疾病。
