一项刊登在PNAS杂志上的研究"Striatum processes reward differently in adolescents versus adults"发现，青少年和成年的大脑在奖赏激励的行为方面的机能具有差别。David Sturman 和Bita Moghaddam比较了青少年和成年大鼠在执行一项有奖赏的任务的时候的大脑活动，包括单个神经元的活动。
这组科研人员训练大鼠把它们的头探进一个洞中从而获得食物颗粒的奖赏，同时记录伏隔核以及背侧纹状体的大脑电活动。这两个大脑区域都与动机性学习有关，但是伏隔核在奖赏过程中起到了更大的作用，而背侧纹状体调控行动选择和习惯的形成。在这些啮齿动物预计到它们的食物奖赏的时候，青少年和成年的这些行为和一般化的大脑活动看上去相同；然而，青少年比成年的背侧纹状体的激活的神经元更多。
这些发现提出，在青少年的大鼠身上，背侧纹状体调控着奖赏对调节行动选择和习惯养成的神经元的直接影响。这组作者说，这项研究可能有助于揭示为什么哺乳动物的青少年比成年表现出了更高的冒险行为以及出现诸如成瘾、抑郁和精神分裂症的趋势增加。这组作者提出，需要进行进一步的研究从而发现这两个年龄组的其他有运作差异的大脑区域，并且确定这类差异如何能够影响行为和精神病问题。（生物谷Bioon.com）
doi:10.1073/pnas.1114137109
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Striatum processes reward differently in adolescents versus adults
David A. Sturman and Bita Moghaddam1
Adolescents often respond differently than adults to the same salient motivating contexts, such as peer interactions and pleasurable stimuli. Delineating the neural processing differences of adolescents is critical to understanding this phenomenon, as well as the bases of serious behavioral and psychiatric vulnerabilities, such as drug abuse, mood disorders, and schizophrenia. We believe that age-related changes in the ways salient stimuli are processed in key brain regions could underlie the unique predilections and vulnerabilities of adolescence. Because motivated behavior is the central issue, it is critical that age-related comparisons of brain activity be undertaken during motivational contexts. We compared single-unit activity and local field potentials in the nucleus accumbens (NAc) and dorsal striatum (DS) of adolescent and adult rats during a reward-motivated instrumental task. These regions are involved in motivated learning, reward processing, and action selection. We report adolescent neural processing differences in the DS, a region generally associated more with learning than reward processing in adults. Specifically, adolescents, but not adults, had a large proportion of neurons in the DS that activated in anticipation of reward. More similar response patterns were observed in NAc of the two age groups. DS single-unit activity differences were found despite similar local field potential oscillations. This study demonstrates that in adolescents, a region critically involved in learning and habit formation is highly responsive to reward. It thus suggests a mechanism for how rewards might shape adolescent behavior differently, and for their increased vulnerabilities to affective disorders.
