Ueno Aya, Abe Nobuhito, Suzuki Maki, Hirayama Kazumi, Mori Etsuro, Tashiro Manabu, Itoh Masatoshi, Fujii Toshikatsu
Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Sendai 980-8575, Japan.
Neuroimage. 2007 Feb 1;34(3):1292-8. doi: 10.1016/j.neuroimage.2006.10.022. Epub 2006 Dec 5.
It is widely accepted that memory traces of an event include various types of information about the content of the event and about the circumstances in which the individual experienced it. However, how these various types of information are stored and later retrieved is poorly understood. One hypothesis postulates that the retrieval of specific event information reactivates regions that were active during the encoding of this information, with the aid of binding functions of the medial temporal lobe (MTL) structures. We used positron emission tomography to identify the brain regions related to the encoding and retrieval of color information. Specifically, we assessed whether overlapping activity was found in both the MTL structures and color-related cortical regions during the encoding and retrieval of color information attached with meaningless shapes. During the study, subjects were asked to encode colored (red or green) and achromatic random shapes. At subsequent testing, subjects were presented with only achromatic shapes, which had been presented with or without colors during encoding, and were engaged in retrieval tasks of shapes and colors. Overlapping activity was found in the MTL and occipital lobe (the lingual and inferior occipital gyri) in the right hemisphere during the encoding and retrieval of meaningless shapes with color information compared with those without color information. Although there are some limitations to be considered, the present findings seem to support the view that the retrieval of specific event information is associated with reactivation of both the MTL structures and the regions involved during encoding of the information.
人们普遍认为，事件的记忆痕迹包括有关该事件内容以及个体经历该事件时所处环境的各种信息。然而，对于这些不同类型的信息是如何存储以及随后如何检索的，我们却知之甚少。一种假说假定，特定事件信息的检索会借助内侧颞叶（MTL）结构的绑定功能，重新激活在该信息编码过程中活跃的区域。我们使用正电子发射断层扫描来识别与颜色信息编码和检索相关的脑区。具体而言，我们评估了在附带无意义形状的颜色信息的编码和检索过程中，MTL结构和与颜色相关的皮质区域是否存在重叠活动。在研究过程中，要求受试者对彩色（红色或绿色）和无彩色的随机形状进行编码。在随后的测试中，仅向受试者呈现无彩色形状，这些形状在编码时曾呈现过或未呈现过颜色，受试者参与形状和颜色的检索任务。与无颜色信息的无意义形状相比，在对带有颜色信息的无意义形状进行编码和检索时，右侧半球的MTL和枕叶（舌回和枕下回）发现了重叠活动。尽管有一些局限性需要考虑，但目前的研究结果似乎支持这样一种观点，即特定事件信息的检索与MTL结构以及信息编码过程中涉及的区域的重新激活有关。
