Integrating rewards and cognition in the frontal cortex
Integrating rewards and cognition in the frontal cortex
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DOI：
10.3758/cabn.4.4.540
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发表时间：
2004-12-04
影响因子：
2.9
通讯作者：
Fiez, Julie A.
中科院分区：
文献类型：
--
作者：
Gilbert, Alison M.;Fiez, Julie A.
研究表明，背外侧前额叶皮层（DLPFC）负责工作记忆和执行控制，而腹侧前额叶皮层（VFC）负责情感和动机处理。很少有研究同时考察这些区域的功能特异性和整合性。我们使用功能磁共振成像和口头工作记忆任务来做到这一点，在这项任务中，视觉线索表明在即将到来的试验中的回忆表现是否与金钱奖励有关。基于先前在非人类灵长类动物延迟反应任务中获得的发现，我们假设(1)VFC只会在暗示可能获得金钱奖励的提示下表现出增加；(2) DLPFC在所有试验中都表现出持续的活动，但在奖励试验中活动会增强；(3)以语音为基础的排练区域对金钱激励相对不敏感。我们关于DLPFC和排练相关区域的假设得到了证实。在VFC区域，我们没有观察到当任务的提示或延迟时期被单独检查时，奖励的统计显著影响。然而，在延迟时期，VFC出现了意想不到的显著失活；此外，事后体素分析表明：(1)任务的提示和延迟时期和(2)试验的奖励价值之间存在复杂的相互作用。不同试验类型的激活和失活模式表明VFC对奖励线索敏感，并且在工作记忆任务的延迟时期，DLPFC和VFC的部分可能相反，以促进任务的执行。
Research indicates that the dorsolateral prefrontal cortex (DLPFC) contributes to working memory and executive control, whereas the ventral frontal cortex (VFC) contributes to affective and motivational processing. Few studies have examined both the functional specificity and the integration of these regions. We did so using fMRI and a verbal working memory task in which visual cues indicated whether recall performance on an upcoming trial would be linked to a monetary reward. On the basis of prior findings obtained in delayed response tasks performed by nonhuman primates, we hypothesized that (1) VFC would show an increase only in response to a cue indicating potential for a monetary reward; (2) DLPFC would show sustained activity across a delay interval for all trials, though activity in rewarded trials would be enhanced; and (3) regions engaged in speech-based rehearsal would be relatively insensitive to monetary incentive. Our hypotheses about DLPFC and rehearsal-related regions were confirmed. In VFC regions, we failed to observe statistically significant effects of reward when the cue or delay epochs of the task were examined in isolation. However, an unexpected and significant deactivation was observed in VFC during the delay epoch; furthermore, a post hoc voxelwise analysis indicated a complex interaction between (1) the cue and delay epochs of the task and (2) the reward value of the trials. The pattern of activation and deactivation across trial types suggests that VFC is sensitive to reward cues, and that portions of DLPFC and VFC may work in opposition during the delay epoch of a working memory task in order to facilitate task performance.