Suzuki Maki, Fujii Toshikatsu, Tsukiura Takashi, Okuda Jiro, Umetsu Atsushi, Nagasaka Tatsuo, Mugikura Shunji, Yanagawa Isao, Takahashi Shoki, Yamadori Atsushi
Division of Neuropsychology, Department of Disability Medicine, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Neuroimage. 2002 Dec;17(4):1790-6. doi: 10.1006/nimg.2002.1303.
Temporal context information is crucial to understanding human episodic memory. Human lesion and neuroimaging data indicate that prefrontal regions are important for retrieving temporal context memory, although the exact nature of their involvement is still unclear. We employed functional magnetic resonance imaging (fMRI) to elucidate the neural basis of two kinds of temporal context memory: the temporal order of items between lists and within a list. On the day of the fMRI experiment, subjects memorized a list of 30 pictures in the morning and another list of 30 pictures in the afternoon. During the scanning session, the subjects performed three tasks. In a between-lists task, they were asked to judge the temporal order between two items that had been presented in different lists. In a within-list task, they were asked to judge the temporal order between two items that had been presented in a single list. We found bilateral prefrontal activities during these two temporal context memory tasks compared with a simple item-recognition task. Furthermore, in direct comparison between these two tasks, we found differential prefrontal activities. Thus, right prefrontal activity was associated with temporal order judgment of items between lists, whereas left prefrontal activity was related to temporal order judgment of items within a list. These results indicate that retrieval processes of two kinds of temporal context memory are supported by different, but overlapping, sets of cerebral regions. We speculate that this reflects different cognitive processes for retrieving temporal context memory between separate episodes and within a single episode.
时间背景信息对于理解人类情景记忆至关重要。人类损伤和神经影像学数据表明，前额叶区域对于检索时间背景记忆很重要，尽管其具体参与方式仍不清楚。我们采用功能磁共振成像（fMRI）来阐明两种时间背景记忆的神经基础：列表之间和列表内项目的时间顺序。在fMRI实验当天，受试者上午记忆了30张图片的列表，下午又记忆了另一组30张图片的列表。在扫描过程中，受试者执行了三项任务。在列表间任务中，他们被要求判断在不同列表中呈现的两个项目之间的时间顺序。在列表内任务中，他们被要求判断在单个列表中呈现的两个项目之间的时间顺序。与简单的项目识别任务相比，我们发现在这两项时间背景记忆任务中双侧前额叶有活动。此外，在这两项任务的直接比较中，我们发现了前额叶活动的差异。因此，右侧前额叶活动与列表间项目的时间顺序判断相关，而左侧前额叶活动与列表内项目的时间顺序判断相关。这些结果表明，两种时间背景记忆的检索过程由不同但重叠的脑区集合支持。我们推测，这反映了在不同情节之间和单个情节内检索时间背景记忆的不同认知过程。
