Functional coupling of human prefrontal and premotor areas during cognitive manipulation
Functional coupling of human prefrontal and premotor areas during cognitive manipulation
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DOI：
10.1523/jneurosci.4273-06.2007
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发表时间：
2007-03-28
影响因子：
5.3
通讯作者：
Fukuyama, Hidenao
中科院分区：
文献类型：
--
作者：
Abe, Mitsunari;Hanakawa, Takashi;Fukuyama, Hidenao
有证据表明，在工作记忆任务的执行过程中，背侧运动前皮层（pre-PMd）的吻侧部分参与其中。然而，目前尚不清楚pmd前的执行功能与背外侧前额叶皮层（DLPFC）的执行功能之间的关系以及这两个区域如何相互作用。使用功能性磁共振成像（fMRI），在延迟编码识别任务期间检查大脑活动。15名被试预先学习了几个四码标准序列和由两个标准序列组成的超序列（SUPs），形成长期记忆的“块”。在功能磁共振成像中，受试者记住以SUP或两个不相连的标准序列（2STs）呈现的八个编码刺激。记忆探针提示受试者识别跨两个块（across）或单个块内的代码。2 × 2因子设计用于测试两种类型的工作记忆操作：(1)从块中选择代码的简化操作（“分段”）和(2)将未链接代码转换为序列的合成操作（“绑定”）。响应时间数据支持每个操作的行为影响。事件相关fMRI显示，“分割操作”激活了双侧DLPFC，而“绑定操作”增强了左侧pmd前活动。腹外侧前额叶皮层的活动表明，它参与了从长期记忆中提取任务相关信息的过程。此外，有效连通性分析表明，左侧前pmd和同侧DLPFC在跨识别2st时特异性相互作用，这两种情况都涉及到。我们提出了工作记忆操作的特定神经基质：用于分割/注意选择的DLPFC和用于结合/测序的pre-PMd。DLPFC和pre-PMd之间的功能耦合似乎在结合这些不同的操作中起作用。
Evidence indicates the involvement of the rostral part of the dorsal premotor cortex (pre-PMd) in executive processes during working memory tasks. However, it remains unclear what the executive function of pre-PMd is in relation to that of the dorsolateral prefrontal cortex (DLPFC) and how these two areas interact. Using functional magnetic resonance imaging (fMRI), brain activity was examined during a delayed-encoding recognition task. Fifteen subjects had prelearned several four-code standard sequences and super sequences (SUPs) consisting of a train of two standard sequences to form "chunks" in long-term memory. During fMRI, subjects remembered eight-code encoding stimuli presented as an SUP or two unlinked standard sequences (2STs). A memory probe prompted the subjects to recognize codes across two chunks (ACROSS) or within a single chunk. A 2 x 2 factorial design was used to test two types of working memory manipulation: (1) a reductive operation selecting codes from chunks ("segmenting") and (2) a synthetic operation converting unlinked codes into a sequence ("binding"). Response time data supported the behavioral effects of each operation. Event-related fMRI showed that the "segmenting operation" activated the DLPFC bilaterally, whereas the " binding operation" enhanced the left pre-PMd activity. Activity in the ventrolateral prefrontal cortex suggested its involvement in the retrieval of task-relevant information from long-term memory. Furthermore, effective connectivity analysis indicated that the left pre-PMd and ipsilateral DLPFC interacted specifically during the ACROSS recognition of 2STs, the condition that involved both operations. We propose specific neural substrates for working memory manipulation: the DLPFC for segmenting/attentional selection and the pre-PMd for binding/sequencing. The functional coupling between the DLPFC and pre-PMd appears to play a role in combining these distinct operations.