School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom.
J Neurosci. 2011 May 11;31(19):7156-62. doi: 10.1523/JNEUROSCI.0295-11.2011.
A novel association can form between two memories even when the events to which they correspond are not physically present. For example, once an integrated memory has formed that binds the (when, where, and what) components of an event together, this memory can be triggered by one of its components, and updated with coincident information in the environment. The neural basis of this form of retrieval-mediated learning is unknown. Here, we show, for the first time, that NMDA receptors in the rat hippocampus are required for retrieval-mediated learning involving episodes, but not for the expression of such learning or for retrieval-mediated learning involving simple associations between the components of episodes. These findings provide a novel insight into learning processes that serve the desirable function of integrating stored information with new information, but whose operation might also provide a substrate for some of the cognitive symptoms of schizophrenia and Alzheimer's disease.
即使两个对应的事件没有同时出现，它们之间也可以形成新的联系。例如，一旦形成了将事件的（何时、何地、何物）组成部分结合在一起的整合记忆，该记忆就可以被其中一个组成部分触发，并与环境中的相关信息更新。这种检索介导的学习形式的神经基础尚不清楚。在这里，我们首次表明，大鼠海马中的 NMDA 受体对于涉及情节的检索介导学习是必需的，但对于这种学习的表达或对于涉及情节组成部分之间简单关联的检索介导学习则不是必需的。这些发现为学习过程提供了新的见解，这些学习过程有助于将存储的信息与新信息整合，但它们的运作也可能为精神分裂症和阿尔茨海默病的一些认知症状提供基础。
