Coordinates activities of retrosplenial ensembles during resting-state encode spatial landmarks. Part 1 of 2

The brain likely uses off-line periods to consolidate recent memories. One hypothesis holds that the hippocampal output provides a unique, global linking or 'index' code for each memory, and that this code is stored in the cortex in association with locally encoded attributes of each memory. Activation of the index code is hypothesized to evoke coordinated memory trace reactivation thus facilitating consolidation. Retrosplenial cortex (RSC) is a major recipient of hippocampal outflow and we have described populations of neurons there with sparse and orthogonal coding characteristics that resemble hippocampal 'place' cells, and whose expression depends on an intact hippocampus. Using two-photon Ca2+ imaging, we recorded ensembles of neurons in the RSC during periods of immobility before and after active running on a familiar linear treadmill track. Synchronous bursting of distinct groups of neurons occurred during rest both prior to and after running. In the second rest epoch, these patt...

大脑大概率会借助离线时段巩固新近形成的记忆。有假说认为，海马体的输出会为每一段记忆提供一种独特的全局性联结编码，或称“索引编码（index code）”，该编码会与记忆的局部编码属性一同储存在大脑皮层中。激活该索引编码被推测可唤起协调一致的记忆痕迹（memory trace）再激活过程，从而促进记忆巩固。压后皮层（retrosplenial cortex, RSC）是海马体输出信号的主要接收脑区，我们此前已描述过该脑区内的神经元群体：它们具备稀疏且正交的编码特征，类似海马体的位置细胞（place cells），且其表达依赖于完整的海马体结构。我们借助双光子钙离子（Ca²+）成像技术，在熟悉的线性跑步机跑道上进行主动奔跑的前后静息时段内，记录了压后皮层内的神经元集群活动。奔跑前后的静息阶段均出现了不同神经元集群的同步爆发式放电活动。在第二个静息时段中，这些模式……