Social and novel contexts modify hippocampal CA2 representations of space.

Georgia M Alexander,Chenguang Zheng,Serena M Dudek,Shannon Farris,Jason R Pirone,Laura L Colgin

doi:10.1038/ncomms10300

Abstract

The hippocampus supports a cognitive map of space and is critical for encoding declarative memory (who, what, when and where). Recent studies have implicated hippocampal subfield CA2 in social and contextual memory but how it does so remains unknown. Here we find that in adult male rats, presentation of a social stimulus (novel or familiar rat) or a novel object induces global remapping of place fields in CA2 with no effect on neuronal firing rate or immediate early gene expression. This remapping did not occur in CA1, suggesting this effect is specific for CA2. Thus, modification of existing spatial representations might be a potential mechanism by which CA2 encodes social and novel contextual information.

Highlights

The hippocampus supports a cognitive map of space and is critical for encoding declarative memory
We use in vivo single neuron recording and immediate early gene (IEG) mapping in male rats to determine how CA2 neurons respond to social and contextual experiences
CA2 neurons have the capacity to update their spatial representations online in response to social or contextual changes in the environment, possibly as a means to encode social and novel contextual information. These results suggest that CA2 place cells may link social and novel contextual information with representations of space

Summary

Introduction

The hippocampus supports a cognitive map of space and is critical for encoding declarative memory (who, what, when and where). We find that in adult male rats, presentation of a social stimulus (novel or familiar rat) or a novel object induces global remapping of place fields in CA2 with no effect on neuronal firing rate or immediate early gene expression. This remapping did not occur in CA1, suggesting this effect is specific for CA2. CA2 neurons have the capacity to update their spatial representations online in response to social or contextual changes in the environment, possibly as a means to encode social and novel contextual information These results suggest that CA2 place cells may link social and novel contextual information with representations of space

Methods

Results

Conclusion