Sava Simona, Markus Etan J
Behavioral Neuroscience Division, Department of Psychology, University of Connecticut, Storrs, Connecticut 06269, USA.
J Neurosci. 2008 Feb 20;28(8):1841-53. doi: 10.1523/JNEUROSCI.4629-07.2008.
When a rat runs through a familiar environment, the hippocampus retrieves a previously stored spatial representation of the environment. When the environment is modified a new representation is seen, presumably corresponding to the hippocampus encoding the new information. The medial septum is hypothesized to modulate whether the hippocampus engages in retrieval or encoding. The cholinergic agonist carbachol was infused into the medial septum, and hippocampal CA1 place cells were recorded in freely moving rats. In a familiar environment, septal activation impaired the retrieval of a previously stored hippocampal place cell representation regardless of age. When the environment was changed, medial septal activation impaired the encoding process in young, but facilitated the encoding of the new information in aged rats. Moreover, the improved encoding was evident during a subsequent exposure to the modified environment 24 h later. The findings support the role the septum plays in modulating hippocampal retrieval/encoding states. Furthermore, our data indicate a mechanism of age-related cognitive impairment.
当一只大鼠在熟悉的环境中奔跑时，海马体会检索先前存储的该环境的空间表征。当环境发生改变时，会出现一种新的表征，推测这对应着海马体对新信息的编码。内侧隔区被认为可以调节海马体是进行检索还是编码。将胆碱能激动剂卡巴胆碱注入内侧隔区，并在自由活动的大鼠中记录海马CA1区位置细胞的活动。在熟悉的环境中，无论年龄大小，隔区激活都会损害先前存储的海马体位置细胞表征的检索。当环境发生变化时，内侧隔区激活会损害年轻大鼠的编码过程，但促进老年大鼠对新信息的编码。此外，在24小时后再次接触改变后的环境时，编码能力的提高很明显。这些发现支持了隔区在调节海马体检索/编码状态中所起的作用。此外，我们的数据表明了一种与年龄相关的认知障碍机制。
