Smith Bruce W, Mitchell Derek G V, Hardin Michael G, Jazbec Sandra, Fridberg Daniel, Blair R James R, Ernst Monique
Department of Psychology, University of New Mexico, USA.
Neuroimage. 2009 Jan 15;44(2):600-9. doi: 10.1016/j.neuroimage.2008.08.016. Epub 2008 Aug 27.
Economic decision-making involves the weighting of magnitude and probability of potential gains/losses. While previous work has examined the neural systems involved in decision-making, there is a need to understand how the parameters associated with decision-making (e.g., magnitude of expected reward, probability of expected reward and risk) modulate activation within these neural systems. In the current fMRI study, we modified the monetary wheel of fortune (WOF) task [Ernst, M., Nelson, E.E., McClure, E.B., Monk, C.S., Munson, S., Eshel, N., et al. (2004). Choice selection and reward anticipation: an fMRI study. Neuropsychologia 42(12), 1585-1597.] to examine in 25 healthy young adults the neural responses to selections of different reward magnitudes, probabilities, or risks. Selection of high, relative to low, reward magnitude increased activity in insula, amygdala, middle and posterior cingulate cortex, and basal ganglia. Selection of low-probability, as opposed to high-probability reward, increased activity in anterior cingulate cortex, as did selection of risky, relative to safe reward. In summary, decision-making that did not involve conflict, as in the magnitude contrast, recruited structures known to support the coding of reward values, and those that integrate motivational and perceptual information for behavioral responses. In contrast, decision-making under conflict, as in the probability and risk contrasts, engaged the dorsal anterior cingulate cortex whose role in conflict monitoring is well established. However, decision-making under conflict failed to activate the structures that track reward values per se. Thus, the presence of conflict in decision-making seemed to significantly alter the pattern of neural responses to simple rewards. In addition, this paradigm further clarifies the functional specialization of the cingulate cortex in processes of decision-making.
经济决策涉及对潜在收益/损失的大小和概率进行权衡。虽然先前的研究已经考察了参与决策的神经系统,但仍有必要了解与决策相关的参数(如预期奖励的大小、预期奖励的概率和风险)如何调节这些神经系统内的激活情况。在当前的功能磁共振成像(fMRI)研究中,我们修改了货币幸运轮(WOF)任务[恩斯特,M.,尼尔森,E.E.,麦克卢尔,E.B.,蒙克,C.S.,芒森,S.,埃舍尔,N.等(2004年)。选择与奖励预期:一项fMRI研究。《神经心理学》42(12),1585 - 1597。],以研究25名健康年轻成年人对不同奖励大小、概率或风险选择的神经反应。相对于低奖励大小,选择高奖励大小会增加脑岛、杏仁核、中扣带回和后扣带回皮质以及基底神经节的活动。与高概率奖励相反,选择低概率奖励会增加前扣带回皮质的活动,选择有风险的奖励(相对于安全奖励)时也是如此。总之,在不涉及冲突的决策中,如大小对比,会激活已知支持奖励值编码的结构,以及那些整合动机和感知信息以产生行为反应的结构。相比之下,在冲突情况下的决策,如概率和风险对比,会激活背侧前扣带回皮质,其在冲突监测中的作用已得到充分证实。然而,冲突情况下的决策未能激活本身追踪奖励值的结构。因此,决策中冲突的存在似乎显著改变了对简单奖励的神经反应模式。此外,该范式进一步阐明了扣带回皮质在决策过程中的功能特化。