根据一项新的报告,一个人对于预料到和收到一份奖赏的反应可能受到遗传因素的影响。这些结果提示,遗传变异可能对寻求奖赏行为的个体差异有贡献,而且可能对一个人的神经精神疾病易感性有贡献。
利用功能磁共振成像(fMRI)技术,Karen Berman及其同事发现,多巴胺传递的差异很可能调控着涉及到奖赏的预期与接受的人类大脑区域的反应。在fMRI大脑扫描中,这组科学家发现携带导致突触中有更多多巴胺的特定多巴胺变异的人们在预料到奖赏以及获得奖赏的时候表现出了神经活化增加。各种神经精神疾病,例如帕金森氏症、精神分裂症、毒品成瘾以及抑郁症也与多巴胺系统的功能障碍有联系。这组作者提出,多巴胺转运体类型的遗传变异可能导致多巴胺再吸收的下降,并最终导致大脑神经突触有更多的多巴胺。(生物谷Bioon.com)
生物谷推荐原始出处:
PNAS December 22, 2008, doi: 10.1073/pnas.0805517106
Variation in dopamine genes influences responsivity of the human reward system
Jean-Claude Drehera,1,2, Philip Kohna,b, Bhaskar Kolachanab, Daniel R. Weinbergerb, and Karen Faith Bermana,b,2
aSection on Integrative Neuroimaging,
bGenes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD 20892-1365
In humans, dopamine neurotransmission is influenced by functional polymorphisms in the dopamine transporter (DAT1) and catechol-O-methyltransferase (COMT) genes. Here, we used event-related functional magnetic resonance imaging to directly investigate the neurofunctional effects of the Val158Met COMT and variable number of tandem repeat DAT1 polymorphisms on distinct components of the reward system in humans. The results revealed a main effect of COMT genotype in the ventral striatum and lateral prefrontal cortex during reward anticipation (P < 0.001, uncorrected) and in the orbitofrontal cortex at the time of reward delivery (P < 0.005), met/met individuals exhibiting the highest activation. The main effect of DAT1 genotype was seen in robust blood-oxygen-level-dependent response differences in the caudate nucleus and ventral striatum during reward anticipation (P < 0.001) and in the lateral prefrontal cortex and midbrain at the time of reward delivery, with carriers of the DAT1 9-repeat allele showing the highest activity. Moreover, an interaction between the COMT and DAT1 genes was found in the ventral striatum and lateral prefrontal cortex during reward anticipation and in the lateral prefrontal and orbitofrontal cortices as well as in the midbrain at the time of reward delivery, with carriers of the DAT1 9-repeat allele and COMT met/met allele exhibiting the highest activation, presumably reflecting functional change consequent to higher synaptic dopamine availability. Taken together, these results indicate that genetically influenced variations in dopamine transmission modulate the response of brain regions involved in anticipation and reception of rewards and suggest that these responses may contribute to individual differences in reward-seeking behavior and in predisposition to neuropsychiatric disorders.