科学家提出，一种遗传的神经基因型比另外一种遗传变异可能为一些个体带来在学习需要迅速和灵活决策的任务方面的优势。此前的研究表明，调控人脑中的多巴胺水平可能促进或妨碍学习，而一种称为COMT的神经递质酶可能影响决策。
Lea Krugel及其同事让26个健康的青年成人接受了有金钱回报的决策测试，从而检验了这一假说。这组科学家报告说，拥有被称为“Val”的遗传变异的个体是更灵活的决策者，而且比拥有被称为“Met”的另一种酶的版本的个体在吸取自己的错误教训方面更快。这组作者提出，拥有“Val”多态的个体在计算可能的回报的时候做出的决定更好，而且能比他们的同事更好地执行任务。功能磁共振成像（fMRI）标明，这种学习优势反映在了受试者前额叶皮层的大脑活动上，该皮层被认为受到了多巴胺代谢的影响。这组科学家说，这些结果表明，多巴胺调控很可能在帮助人们进行影响未来的决策过程中考虑到过去的情况方面扮演着一个关键角色。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS October 12, 2009, doi: 10.1073/pnas.0905191106
Genetic variation in dopaminergic neuromodulation influences the ability to rapidly and flexibly adapt decisions
Lea K. Krugela,b,c,1, Guido Bielea,b,c, Peter N. C. Mohra,b,c, Shu-Chen Lia,c and Hauke R. Heekerena,b,c,1
aNeurocognition of Decision Making, Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany;
bMax Planck Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1a, 04103 Leipzig, Germany; and
cNeuroscience Research Center and Berlin NeuroImaging Center, Charité University Medicine Berlin, Schumannstrasse 20/21, 10117 Berlin, Germany
The ability to rapidly and flexibly adapt decisions to available rewards is crucial for survival in dynamic environments. Reward-based decisions are guided by reward expectations that are updated based on prediction errors, and processing of these errors involves dopaminergic neuromodulation in the striatum. To test the hypothesis that the COMT gene Val158Met polymorphism leads to interindividual differences in reward-based learning, we used the neuromodulatory role of dopamine in signaling prediction errors. We show a behavioral advantage for the phylogenetically ancestral Val/Val genotype in an instrumental reversal learning task that requires rapid and flexible adaptation of decisions to changing reward contingencies in a dynamic environment. Implementing a reinforcement learning model with a dynamic learning rate to estimate prediction error and learning rate for each trial, we discovered that a higher and more flexible learning rate underlies the advantage of the Val/Val genotype. Model-based fMRI analysis revealed that greater and more differentiated striatal fMRI responses to prediction errors reflect this advantage on the neurobiological level. Learning rate-dependent changes in effective connectivity between the striatum and prefrontal cortex were greater in the Val/Val than Met/Met genotype, suggesting that the advantage results from a downstream effect of the prefrontal cortex that is presumably mediated by differences in dopamine metabolism. These results show a critical role of dopamine in processing the weight a particular prediction error has on the expectation updating for the next decision, thereby providing important insights into neurobiological mechanisms underlying the ability to rapidly and flexibly adapt decisions to changing reward contingencies.
