Journal
HIPPOCAMPUS
Volume 31, Issue 3, Pages 244-260Publisher
WILEY
DOI: 10.1002/hipo.23272
Keywords
behavior; calcium imaging; memory; stability
Categories
Funding
- National Institutes of Health [MH060013, MH120073, R01 MH 051570, R01 MH052090]
- U.S. Office of Naval Research MURI [MURI N00014-16-1-2832, MURI N00014-19-1-2571]
Ask authors/readers for more resources
The study showed that hippocampal neurons in mice undergo continual replacement during task performance, leading to memory reorganization even in the absence of behavioral changes.
The population of hippocampal neurons actively coding space continually changes across days as mice repeatedly perform tasks. Many hippocampal place cells become inactive while other previously silent neurons become active, challenging the idea that stable behaviors and memory representations are supported by stable patterns of neural activity. Active cell replacement may disambiguate unique episodes that contain overlapping memory cues, and could contribute to reorganization of memory representations. How active cell replacement affects the evolution of representations of different behaviors within a single task is unknown. We trained mice to perform a delayed nonmatching to place task over multiple weeks, and performed calcium imaging in area CA1 of the dorsal hippocampus using head-mounted miniature microscopes. Cells active on the central stem of the maze split their calcium activity according to the animal's upcoming turn direction (left or right), the current task phase (study or test), or both task dimensions, even while spatial cues remained unchanged. We found that, among reliably active cells, different splitter neuron populations were replaced at unequal rates, resulting in an increasing number of cells modulated by turn direction and a decreasing number of cells with combined modulation by both turn direction and task phase. Despite continual reorganization, the ensemble code stably segregated these task dimensions. These results show that hippocampal memories can heterogeneously reorganize even while behavior is unchanging.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available