The neural substrate and temporal dynamics of interference effects in working memory as revealed by event-related functional MRI
The neural substrate and temporal dynamics of interference effects in working memory as revealed by event-related functional MRI
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DOI：
10.1073/pnas.96.13.7514
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发表时间：
1999-06-22
影响因子：
11.1
通讯作者：
Smith, EE
中科院分区：
文献类型：
--
作者：
D'Esposito, M;Postle, BR;Smith, EE
对猴子和人类前额叶皮层（PFC）的研究表明，该区域支持多种多样的心理过程，这些心理过程有助于许多复杂的行为，如工作记忆。其中一些过程的解剖学证据来自使用封闭实验设计的功能性神经成像实验，这些实验平均了男性试验所有组成部分的信号，因此不能将不同时间过程的不同过程分离开来。使用事件相关的功能性核磁共振成像，我们能够暂时分离出与项目识别任务的目标呈现、延迟和探测部分有关的过程的神经关联。两种类型的试验最令人感兴趣：近期阴性试验；这些探针与前两次试验的目标集合中的一个项目相匹配，而不是现在，以及那些具有非最近阴性探针的人，他们与现在或前两次试验的目标项目都不匹配。两种试验类型在目标呈现（即编码）或延迟期（即主动维持）PFC激活方面没有差异，但在左腹侧PFC内，与探测期相关的近期阴性激活明显大于非近期阴性激活。这些发现在空间和时间上表征了一种主动干扰效应，可能反映了pfc介导的反应抑制机制的运作，该机制有助于工作记忆的表现。
Research on the prefrontal cortex (PFC) of monkey and humans indicates that this region supports a heterogeneous repertoire of mental processes that contribute to many complex behaviors, such as working memory. Anatomical evidence for some of these processes derives from functional neuroimaging experiments using blocked experimental designs, which average signal across all components of manly trials and therefore cannot dissociate distinct processes with different time courses. Using event-related functional MRI, we were able to isolate temporally the neural correlates of processes contributing to the target presentation, delay, and probe portions of an item-recognition task. Two types of trials were of greatest interest: those with Recent Negative; probes that matched an item from the target set of the previous, but not the present, two trials, and those with Nonrecent Negative probes that did not match a target item from either the present or the two previous trials. There Has no difference between the tno trial types in target presentation (i.e, encoding) or delay-period (i.e,, active maintenance) PFC activation, but there was significantly greater activation for Recent Negatives than Nonrecent Negative activation associated with the probe period within left ventrolateral PFC, These findings characterize spatially and temporally a proactive interference effect that may reflect the operation of a PFC-mediated response-inhibition mechanism that contributes to working memory performance.