Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
Cereb Cortex. 2022 Aug 22;32(17):3602-3610. doi: 10.1093/cercor/bhab436.
The rat retrosplenial cortex (RSC) makes critical contributions to learning and memory but these contributions may not be uniform along its rostro-caudal axis. Previous work suggests that event-related and context-related information are differentially encoded by anterior and posterior RSC subregions. Here, we further test this idea using a procedure in which spatial/environmental cues (context) and discrete event memories are acquired separately. All animals received a 5-min pre-exposure to the training context 24 h before contextual fear conditioning where shock was delivered immediately upon being placed in the chamber. Rats were tested for memory for the context the next day. We found that optogenetic inhibition of cells in only the posterior RSC during the pre-exposure phase, when spatial information is encoded, reduced behavioral responding during the subsequent memory test. However, similar inhibition of either the anterior or posterior RSC during shock delivery, when information about both the context and the shock become integrated, impaired memory. Finally, inhibiting cellular activity in only the posterior RSC during memory retrieval during testing reduced responding. Together, these results suggest that while activity in both subregions is needed during the period in which the event-related information becomes integrated with the context representation, the posterior RSC is important for both memory formation and retrieval or expression of memory for information about the context. These results add to a growing literature demonstrating a role for the RSC in integration of multiple aspects of memory, and provide information on how spatial representations reliant on the retrosplenial cortex interact with associative learning.
大鼠后隔区（RSC）对学习和记忆有重要贡献，但这些贡献在其头尾部可能并不均匀。以前的工作表明，事件相关和上下文相关的信息由 RSC 的前、后区域以不同的方式编码。在这里，我们使用一种程序进一步测试了这个想法，该程序中空间/环境线索（上下文）和离散事件记忆分别被获取。所有动物在进行情境恐惧条件反射之前 24 小时接受 5 分钟的训练环境预暴露，即在进入室时立即给予电击。第二天，对大鼠进行记忆测试。我们发现，在预暴露阶段，即空间信息被编码时，仅在后 RSC 中进行光遗传学抑制细胞，会减少随后的记忆测试中的行为反应。然而，在电击传递期间，即当环境和电击的信息被整合时，无论是在前 RSC 还是后 RSC 中进行类似的抑制，都会损害记忆。最后，在测试期间仅在记忆检索过程中抑制后 RSC 中的细胞活动会减少反应。这些结果表明，虽然两个区域的活动在事件相关信息与环境表示整合的时期是必要的，但后 RSC 对于记忆形成和检索或表达关于环境的信息的记忆都很重要。这些结果增加了越来越多的文献，证明了 RSC 在整合记忆的多个方面的作用，并提供了关于依赖后隔区的空间表示如何与联想学习相互作用的信息。
