Correlation Across Environments Encoded by Hippocampal Place Cells

TL;DR

This paper demonstrates that hippocampal CA3 place cells encode environment correlations with representations resistant to noise, supporting the large capacity of hippocampal spatial memory networks.

Contribution

We replicate and extend prior findings by analyzing the robustness of hippocampal representations to noise and their similarity across environments.

Findings

Correlations between firing rates are partially resistant to noise.

Spatial representations show similar patterns across different environments.

Results support the large capacity of hippocampal CA3 network.

Abstract

The hippocampus is often attributed to episodic memory formation and storage in the mammalian brain; in particular, Alme et al. showed that hippocampal area CA3 forms statistically independent representations across a large number of environments, even if the environments share highly similar features. This lack of overlap between spatial maps indicates the large capacity of the CA3 circuitry. In this paper, we support the argument for the large capacity of the CA3 network. To do so, we replicate the key findings of Alme et al. and extend the results by perturbing the neural activity encodings with noise and conducting representation similarity analysis (RSA). We find that the correlations between firing rates are partially resistant to noise, and that the spatial representations across cells show similar patterns, even across different environments. Finally, we discuss some theoretical and practical implications of our results.