大多数人曾有过“似曾相识”的经历。美国研究人员已经确定导致这一感觉发生的大脑区域，并认为这一发现有助于治疗与记忆力相关的疾病。
据路透社８日报道，麻省理工学院生物学和神经科学教授利根川进和同事在《科学》杂志上发表了这一研究结果。
研究人员说，大脑记忆中心有一部分神经细胞被称作海马状突起。当人来到新地方、有新经历时，这部分神经细胞会就此“画”出一份记忆“地图”，然后把这些记忆藏起来，以备后用。
然而如果有两次经历非常相似，它们的“地图”会重合，变得不清楚。
利根川进说，这一情况发生时，大脑就会出现似曾相识的感觉。实际上，这只是因为大脑对新信息，也就是情景记忆，进行分类时发生了功能故障。
利根川进说：“这种功能对像人类这样的智慧生物而言非常重要。有了它，你知道身边发生了什么事，并能在稍后回想起来。”
他还说，大脑的这种功能随着年龄增长而逐渐衰退，这在老年痴呆症患者身上尤为明显。根据他们的研究结果，人们有希望开发出药物改进这一功能。（生物谷援引新华网）
原始出处:
Published Online June 7, 2007
Science DOI: 10.1126/science.1140263
Research Articles
Submitted on January 23, 2007
Accepted on May 23, 2007
Dentate Gyrus NMDA Receptors Mediate Rapid Pattern Separation in the Hippocampal Network
Thomas J. McHugh 1, Matthew W. Jones 2, Jennifer J. Quinn 3, Nina Balthasar 4, Roberto Coppari 5, Joel K. Elmquist 5, Bradford B. Lowell 6, Michael S. Fanselow 7, Matthew A. Wilson 8, Susumu Tonegawa 1*
1 The Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2 The Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Present address: Department of Physiology, University of Bristol, Bristol BS8 1TD, UK.
3 Department of Psychology, University of California-Los Angeles, Los Angeles, CA 90095, USA; Present address: Division of Molecular Psychiatry, Yale University, New Haven, CT 06508, USA.
4 Division of Endocrinology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Present address: Department of Physiology, University of Bristol, Bristol BS8 1TD, UK.
5 Division of Endocrinology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Present address: Center for Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
6 Division of Endocrinology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
7 Department of Psychology, University of California-Los Angeles, Los Angeles, CA 90095, USA.
8 The Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
* To whom correspondence should be addressed.
Susumu Tonegawa , E-mail: tonegawa@mit.edu
Abstract
Forming distinct representations of multiple contexts, places and episodes is a crucial function of the hippocampus. The dentate gyrus subregion has been suggested to fulfill this role. We have tested this hypothesis by generating and analyzing a mouse strain that lacks the gene encoding the essential subunit of the N-methyl-D-aspartate (NMDA) receptor, NR1, specifically in dentate gyrus granule cells. The mutant mice performed normally in contextual fear conditioning, but were impaired in the ability to distinguish two similar contexts. A significant reduction in the context-specific modulation of firing rate was observed in the CA3 pyramidal cells when the mutant mice were transferred from one context to another. These results provide evidence that NMDA receptors in the granule cells of the dentate gyrus play a crucial role in the process of pattern separation.
