Investigating the entorhinal code for spatial navigation
Abstract/Contents
- Abstract
- Navigation through an environment to a remembered location is a critical skill we use every day, and accurate navigation is necessary for survival for many animals. How do neural cir-cuits accomplish such a task? Over the last few decades, several lines of evidence have suggested that a brain region called medial entorhinal cortex (MEC) supports navigation by encoding information about location and movement within an environment. In particular, MEC contains grid cells, which are cells that encode current position by firing in specific loca-tions that tessellate an environment. Beyond grid cells, MEC has also been found to contain a variety of direction, speed, and position-modulated cells, which encode navigational variables in dynamic and heterogeneous ways. Despite the wealth of knowledge quickly amassing re-garding the role of this region in navigation, several key questions have arisen regarding the degree to which external or internal variates (e.g. landmarks or animal state) can influence entorhinal coding properties, how these properties influence downstream regions, and how we can statistically capture the wide diversity of coding properties found in MEC. Over the course of my PhD work, I used a combination of rodent in vivo electrophysiology, behavioral exper-iments, and computational and statistical modeling to address these questions. In this dissertation, I first present evidence supporting a model in which grid cells use input from en-vironmental landmarks to update their position code. Second, I employ computational models that reveal how changes to grid cell patterns alter the stability of downstream codes for space in the hippocampus. Third, I apply a statistical modeling framework that uncovers heteroge-neous entorhinal coding for navigational variables in an unbiased manner, and reveals more mixed selectivity, heterogeneity, and adaptivity based on running speed than previously thought. Finally, by recording entorhinal activity during tasks with different reward structure, I reveal that grid and other spatial-coding cells modulate their activity with reward. Combined, my thesis work probes how external variates, like boundaries or reward, or internal variates, like animal state, influence entorhinal coding properties, and suggests that entorhinal cortex uses flexible representations of navigationally-relevant information to support spatial naviga-tion.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Hardcastle, Kiah |
|---|---|
| Degree supervisor | Ganguli, Surya, 1977- |
| Degree supervisor | Giocomo, Lisa |
| Thesis advisor | Ganguli, Surya, 1977- |
| Thesis advisor | Giocomo, Lisa |
| Thesis advisor | Baccus, Stephen A |
| Thesis advisor | McClelland, James L |
| Thesis advisor | Raymond, Jennifer L |
| Degree committee member | Baccus, Stephen A |
| Degree committee member | McClelland, James L |
| Degree committee member | Raymond, Jennifer L |
| Associated with | Stanford University, Neurosciences Program. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Kiah Hardcastle. |
|---|---|
| Note | Submitted to the Neurosciences Program. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Kiah Hardcastle
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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