科學(xué)家提出,，一種遺傳的神經(jīng)基因型比另外一種遺傳變異可能為一些個(gè)體帶來在學(xué)習(xí)需要迅速和靈活決策的任務(wù)方面的優(yōu)勢。此前的研究表明,，調(diào)控人腦中的多巴胺水平可能促進(jìn)或妨礙學(xué)習(xí),，而一種稱為COMT的神經(jīng)遞質(zhì)酶可能影響決策。
Lea Krugel及其同事讓26個(gè)健康的青年成人接受了有金錢回報(bào)的決策測試,，從而檢驗(yàn)了這一假說,。這組科學(xué)家報(bào)告說，擁有被稱為“Val”的遺傳變異的個(gè)體是更靈活的決策者,，而且比擁有被稱為“Met”的另一種酶的版本的個(gè)體在吸取自己的錯(cuò)誤教訓(xùn)方面更快,。這組作者提出，擁有“Val”多態(tài)的個(gè)體在計(jì)算可能的回報(bào)的時(shí)候做出的決定更好,，而且能比他們的同事更好地執(zhí)行任務(wù),。功能磁共振成像（fMRI）標(biāo)明，這種學(xué)習(xí)優(yōu)勢反映在了受試者前額葉皮層的大腦活動(dòng)上,，該皮層被認(rèn)為受到了多巴胺代謝的影響,。這組科學(xué)家說，這些結(jié)果表明,，多巴胺調(diào)控很可能在幫助人們進(jìn)行影響未來的決策過程中考慮到過去的情況方面扮演著一個(gè)關(guān)鍵角色,。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
