一項刊登在PNAS雜志上的研究"Striatum processes reward differently in adolescents versus adults"發(fā)現(xiàn),，青少年和成年的大腦在獎賞激勵的行為方面的機(jī)能具有差別。David Sturman 和Bita Moghaddam比較了青少年和成年大鼠在執(zhí)行一項有獎賞的任務(wù)的時候的大腦活動,，包括單個神經(jīng)元的活動,。
這組科研人員訓(xùn)練大鼠把它們的頭探進(jìn)一個洞中從而獲得食物顆粒的獎賞，同時記錄伏隔核以及背側(cè)紋狀體的大腦電活動,。這兩個大腦區(qū)域都與動機(jī)性學(xué)習(xí)有關(guān),，但是伏隔核在獎賞過程中起到了更大的作用，而背側(cè)紋狀體調(diào)控行動選擇和習(xí)慣的形成,。在這些嚙齒動物預(yù)計到它們的食物獎賞的時候,，青少年和成年的這些行為和一般化的大腦活動看上去相同；然而,，青少年比成年的背側(cè)紋狀體的激活的神經(jīng)元更多,。
這些發(fā)現(xiàn)提出，在青少年的大鼠身上,，背側(cè)紋狀體調(diào)控著獎賞對調(diào)節(jié)行動選擇和習(xí)慣養(yǎng)成的神經(jīng)元的直接影響,。這組作者說，這項研究可能有助于揭示為什么哺乳動物的青少年比成年表現(xiàn)出了更高的冒險行為以及出現(xiàn)諸如成癮,、抑郁和精神分裂癥的趨勢增加。這組作者提出,，需要進(jìn)行進(jìn)一步的研究從而發(fā)現(xiàn)這兩個年齡組的其他有運(yùn)作差異的大腦區(qū)域,，并且確定這類差異如何能夠影響行為和精神病問題。（生物谷Bioon.com）
doi:10.1073/pnas.1114137109
PMC:
PMID:
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.
