Role of medial cortical, hippocampal and striatal interactions during cognitive set-shifting
Role of medial cortical, hippocampal and striatal interactions during cognitive set-shifting
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DOI：
10.1016/j.neuroimage.2008.12.040
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发表时间：
2009-05-01
期刊：
影响因子：
5.7
通讯作者：
Yeh, Ing Berne
中科院分区：
文献类型：
--
作者：
Graham, Steven;Phua, Elaine;Yeh, Ing Berne
到目前为止，很少有研究研究涉及复杂的执行功能任务，如认知定势转换的大脑区域的功能连接。在这项研究中，18名健康志愿者在接受功能性磁共振成像的同时进行了一项认知定势转换任务，该任务是从威斯康星州卡片分类测试中修改而来的。这些modi。阳离子允许更好地消除认知过程之间的歧义，并揭示了几个新的发现：1）在发信号通知规则改变的负反馈的第一个实例中尾状核中的峰值激活，2）一旦规则已经被识别，尾状核激活最低，3）一旦规则的身份已经被建立，海马激活峰值，以及4）在新规则候选的生成期间减少海马激活。这种认知定势转换事件的激活模式表明，当新规则的身份未知时，尾状核在反应生成中发挥作用。相反，海马激活的相互模式表明，海马有助于巩固关于正确的刺激-刺激关联的知识，一旦规则改变，这些关联就变得不合适了。使用格兰杰因果映射的功能连接分析显示，尾状核和海马区通过涉及内侧眶额和后扣带回区的回路间接相互作用，已知这些回路基于从任务相关反馈建立的期望将注意力偏向刺激。两者合计，证据表明，这些内侧区域可能介导纹状体-海马的相互作用，从而影响目标导向的注意力从基于刺激-奖励策略（尾状核依赖）的反应策略转变为基于刺激-刺激关联（尾状核依赖）的反应策略。(C)2008年爱思唯尔公司All rights reserved.
To date, few studies have examined the functional connectivity of brain regions involved in complex executive function tasks, such as cognitive set-shifting. In this study, eighteen healthy volunteers performed a cognitive set-shifting task modified from the Wisconsin card sort test while undergoing functional magnetic resonance imaging. These modi. cations allowed better disambiguation between cognitive processes and revealed several novel findings: 1) peak activation in the caudate nuclei in the first instance of negative feedback signaling a shift in rule, 2) lowest caudate activation once the rule had been identified, 3) peak hippocampal activation once the identity of the rule had been established, and 4) decreased hippocampal activation during the generation of new rule candidates. This pattern of activation across cognitive set-shifting events suggests that the caudate nuclei play a role in response generation when the identity of the new rule is unknown. In contrast, the reciprocal pattern of hippocampal activation suggests that the hippocampi help consolidate knowledge about the correct stimulus-stimulus associations, associations that become inappropriate once the rule has changed. Functional connectivity analysis using Granger Causality Mapping revealed that caudate and hippocampal regions interacted indirectly via a circuit involving the medial orbitofrontal and posterior cingulate regions, which are known to bias attention towards stimuli based on expectations built up from task-related feedback. Taken together, the evidence suggests that these medial regions may mediate striato-hippocampal interactions and hence affect goal-directed attentional transitions from a response strategy based on stimulus-reward heuristics (caudate-dependent) to one based on stimulus-stimulus associations (hippocampus-dependent). (C) 2008 Elsevier Inc. All rights reserved.