Charting the hippocampal cognitive map: Investigating the emergence of grid cell and place cell firing patterns in novel and familiar environments

Hippocampal place cells comprise the main building blocks of the cognitive map which is used to encode our surroundings quickly and rapidly. Prominent theoretical models argue that place cells emerge via a linear summation of different grid cells from the medial entorhinal cortex. However, recent experimental evidence shows place cells emerging in novel environments without grid cells. The experimental framework of this thesis is guided by the Field-boundary interaction model which argues that place cells may play a more fundamental role in shaping the emerging grid cell spatial pattern in novel environments. We show that over a three-hour novel environment trial place and size-matched grid fields display similar field size convergence dynamics. This is to be expected if place cells contribute to grid cell formation. However, grid cells also show an initial grid-like spatial pattern, as well as similar convergence rates across modules, indicating that their convergence is governed by internal entorhinal neural network properties. Overall, it can be hypothesized that the influence of place cells on the emerging grid cell pattern has been underestimated. Field-boundary interaction model also predicts that boundaries will influence nearby emerging grid and place fields. In large familiar environments with different western boundary configurations, we establish that Compression has a limited range, while Expansion has a more global effect on the grid cell spatial pattern. In both configurations place cells form multiple fields which show large and heterogeneous shifts throughout the environment. Lastly, we explore how multi-field place cells emerge in familiar and novel virtual reality 1D tracks. Comparable to real environment studies, on shorter tracks place cells mostly from single fields, while on longer tracks majority of place cells produce multiple fields. On a novel track single field cells gradually converge until stability, in contrast to multi-field cells which display non-monotonic convergence dynamics. Overall, the results of this thesis further our understanding of the emergence of the hippocampal cognitive map.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2023

Author dc:creator

• Krstulovic, Marino

Advisor dc:contributor.advisor

• Krupic, Julija

• Cognitive Map
• Grid Cells
• Hippocampus
• Place cells
• Split 3

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/cd5e12bd-64fc-4df5-be75-fe2c80299f44/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.111377

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/372508