Modulation of ventral striatal activity by cognitive effort.
Modulation of ventral striatal activity by cognitive effort.
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DOI：
10.1016/j.neuroimage.2016.12.029
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发表时间：
2017-02-15
期刊：
影响因子：
5.7
通讯作者：
Tricomi E
中科院分区：
文献类型：
--
作者：
Dobryakova E;Jessup RK;Tricomi E
努力折扣理论认为，如果一个奖励是努力获得的，那么它的价值应该更低，而对比理论则认为，代价高昂的努力和奖励之间的对比使奖励看起来更有价值。为了验证这些假设，我们使用了功能性磁共振成像（fMRI），当参与者参与基于反馈的学习时，他们需要低或高的认知努力来获得积极的反馈，而反馈提供的客观信息量保持不变。在低努力条件下，单个图像有四个回答选项。在高努力条件下，呈现两幅图像，每幅图像有两个反应选项，只有当参与者对两幅图像都做出正确反应时，才会呈现正确的反馈。在高努力条件下，准确率明显较低，所有参与者都报告说高努力条件更难。对反馈值敏感的腹侧纹状体区域在控制随机反馈的相应控制条件的激活时，也显示出与低努力条件相关的高努力条件的反馈呈现的激活增加。这些结果表明，认知努力的增加会导致与正反馈相关的腹侧纹状体活动相应增加，这与对比理论的预测一致。获得来之不易的内在奖励，如积极反馈，可能特别有可能促进与奖励相关的大脑活动。
Effort discounting theory suggests that the value of a reward should be lower if it was effortful to obtain, whereas contrast theory suggests that the contrast between the costly effort and the reward makes the reward seem more valuable. To test these alternative hypotheses, we used functional magnetic resonance imaging (fMRI) as participants engaged in feedback-based learning that required low or high cognitive effort to obtain positive feedback, while the objective amount of information provided by feedback remained constant. In the low effort condition, a single image was presented with four response options. In the high effort condition, two images were presented, each with two response options, and correct feedback was presented only when participants responded correctly to both of the images. Accuracy was significantly lower for the high effort condition, and all participants reported that the high effort condition was more difficult. A region of the ventral striatum selected for sensitivity to feedback value also showed increased activation to feedback presentation associated with the high effort condition relative to the low effort condition, when controlling for activation from corresponding control conditions where feedback was random. These results suggest that increased cognitive effort produces corresponding increases in positive feedback-related ventral striatum activity, in line with the predictions made by contrast theory. The accomplishment of obtaining a hard-earned intrinsic reward, such as positive feedback, may be particularly likely to promote reward-related brain activity.