Interference with performance of a response selection task that has no working memory component: An rTMS comparison of the dorsolateral prefrontal and medial frontal cortex
Interference with performance of a response selection task that has no working memory component: An rTMS comparison of the dorsolateral prefrontal and medial frontal cortex
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DOI：
10.1162/089892901753294392
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发表时间：
2001-11-15
影响因子：
3.2
通讯作者：
Rothwell, JC
中科院分区：
文献类型：
--
作者：
Hadland, KA;Rushworth, MFS;Rothwell, JC
有人认为，背外侧前额叶皮层（DLPFC）参与自由选择（FS），即受试者自己决定要做什么动作的过程。成像研究表明，当受试者随机产生反应时，DLPFC会被激活，这为这一建议提供了证据。然而，这些反应、选择任务具有隐藏的工作记忆元素，并且已经广泛报道了当受试者执行涉及工作记忆的任务时，DLPFC被激活。本实验的主要目的是确定DLPFC是否真正参与反应选择。我们使用重复经颅磁刺激（rTMS）来研究暂时干扰DLPFC是否会破坏没有工作记忆成分的反应选择任务的表现。受试者完成的任务是用双手连续做八个不重复的手指动作。在FS任务中，受试者随机选择他们的动作，而计算机显示器显示这些动作。这种视觉反馈消除了受试者“在线”保持先前动作的需要。两个控制任务不需要选择，因为反应是由视觉显示提示的。在高负荷（HL）任务中，被试需要在整个过程中保持注意力，但在低负荷（LL）任务中不存在这种要求，在DLPFC上的rTMS减慢了FS任务和HL任务序列结束时的反应时间，但对LL任务没有影响。内侧额叶皮层（MFC）的rTMS减慢了FS任务的反应时间，但对HL任务没有影响。这表明，没有工作记忆负荷的响应选择任务将取决于DLPFC和MFC。不同之处在于，DLPFC在选择竞争反应或集中注意力时很重要，但MFC只在反应选择任务中很重要。
It has been suggested that the dorsolateral prefrontal cortex (DLPFC) is involved in free selection (FS), the process by which subjects themselves decide what action to perform. Evidence for this proposal has been provided by imaging studies showing activation of the DLPFC when subjects randomly generate responses. However, these response,selection tasks have a hidden working memory element and it has been widely reported that the DLPFC is activated when subjects perform tasks which involve working memory. The primary aim of this experiment was to establish if the DLPFC is genuinely involved in response selection. We used repetitive transcranial magnetic stimulation (rTMS`) to investigate whether temporary interference of the DLPFC could disrupt performance of a response selection task that had no working memory component. Subjects performed tasks in which they made bimanual sequences of eight nonrepeating finger movements. In the FS task, subjects chose their movements at random while a computer monitor displayed these moves. This visual feedback obviated the need for subjects to maintain their previous moves "on-line." No selection was required for the two control tasks as responses were cued by the visual display. The attentional demands of the control tasks varied, In the high load (HL) version, subjects had to maintain their attention throughout the sequence, but this requirement was absent in the low load (LL) task, rTMS over the DLPFC slowed response times on the FS task and at the end of the sequence on the HL task, but had no effect on the LL task. rTMS over the medial frontal cortex (MFC) slowed response times on the FS task but had no effect on the HL task. This suggests that a response selection task without a working memory load will depend on the DLPFC and the MFC. The difference appears to be that the DLPFC is important when selecting between competing responses or when concentrating if there is a high attentional demand, but that the MFC is only important during the response selection task.