# Spatial Codes Across the Medial Entorhinal Cortex for Memory and Navigation

> **NIH NIH R56** · STANFORD UNIVERSITY · 2020 · $398,149

## Abstract

A central function of the brain is to create internal representations of stimuli and experiences from the outside
world to guide behavior. Here, we examine the circuit mechanisms underlying the neural representation of
external space, a representation essential to spatial memory and navigation, and impacted by neurodegenerative
and psychiatric diseases. The neural basis for the representation of space depends, in part, on circuits in the
medial entorhinal cortex, which translate the external environment into an internal map of space. The resolution
of the entorhinal neural map of space is topographically organized, with the firing rate tuning curves of spatial
and directional neurons progressively increasing along the dorsal to ventral entorhinal axis. This topography has
been proposed to allow dorsal versus ventral entorhinal neural codes to support different behaviors, with dorsal
regions playing a larger role in spatial learning. While our previous work revealed that the dorsal to ventral
gradient in the spatial scale of entorhinal representations impacts spatial memory, the degree to which dorsal
versus ventral neural codes for spatial position act as discrete or coordinated circuits to support spatial memory
or navigation remains incompletely understood. Here, we propose to combine electrophysiology using silicon
probes with spatial and memory tasks in behaving mice. Until now, electrophysiological approaches had to
contend with the difficulty of accessing ventral cortical regions and limited recording channel counts, resulting in
a lack of studies in which the activity of entorhinal neurons were simultaneously considered across the dorsal-
ventral axis. However, new versions of silicon probes have allowed us to record hundreds (>500) of neurons
simultaneously along nearly the entire length of mouse entorhinal cortex. This, combined with virtual reality tasks
that can rapidly incorporate a diverse set of sensory and non-metric (positive or negative stimuli) cues, will enable
us to reveal how neural activity across the dorsal-ventral entorhinal axis is restructured after learning about
important environmental features and how this information is then communicated across the entorhinal structure
to drive behavior. Achieving significant insight along these fonts will provide a novel understanding of how
entorhinal maps of space support spatial memory and navigation.

## Key facts

- **NIH application ID:** 10120754
- **Project number:** 2R56MH106475-06
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Lisa Giocomo
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $398,149
- **Award type:** 2
- **Project period:** 2015-09-25 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10120754

## Citation

> US National Institutes of Health, RePORTER application 10120754, Spatial Codes Across the Medial Entorhinal Cortex for Memory and Navigation (2R56MH106475-06). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10120754. Licensed CC0.

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