Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1

The hippocampus is believed to encode episodic memory by binding information about the content of experience within a spatiotemporal framework encoding the location and temporal context of that experience. Previous work implies a distinction between positional inputs to the hippocampus from upstream...

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Main Authors: William Hockeimer, Ruo-Yah Lai, Maanasa Natrajan, William Snider, James J Knierim
Format: Article
Language:English
Published: eLife Sciences Publications Ltd 2025-04-01
Series:eLife
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Online Access:https://elifesciences.org/articles/85599
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author William Hockeimer
Ruo-Yah Lai
Maanasa Natrajan
William Snider
James J Knierim
author_facet William Hockeimer
Ruo-Yah Lai
Maanasa Natrajan
William Snider
James J Knierim
author_sort William Hockeimer
collection DOAJ
description The hippocampus is believed to encode episodic memory by binding information about the content of experience within a spatiotemporal framework encoding the location and temporal context of that experience. Previous work implies a distinction between positional inputs to the hippocampus from upstream brain regions that provide information about an animal’s location and nonpositional inputs which provide information about the content of experience, both sensory and navigational. Here, we leverage the phenomenon of ‘place field repetition’ to better understand the functional dissociation between positional and nonpositional information encoded in CA1. Rats navigated freely on a novel maze consisting of linear segments arranged in a rectilinear, city-block configuration, which combined elements of open-field foraging and linear-track tasks. Unlike typical results in open-field foraging, place fields were directionally tuned on the maze, even though the animal’s behavior was not constrained to extended, one-dimensional (1D) trajectories. Repeating fields from the same cell tended to have the same directional preference when the fields were aligned along a linear corridor of the maze, but they showed uncorrelated directional preferences when they were unaligned across different corridors. Lastly, individual fields displayed complex time dynamics which resulted in the population activity changing gradually over the course of minutes. These temporal dynamics were evident across repeating fields of the same cell. These results demonstrate that the positional inputs that drive a cell to fire in similar locations across the maze can be behaviorally and temporally dissociated from the nonpositional inputs that alter the firing rates of the cell within its place fields, offering a potential mechanism to increase the flexibility of the system to encode episodic variables within a spatiotemporal framework provided by place cells.
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spelling doaj-art-580eeca7543c4b168bcf941d33946fbb2025-08-20T03:53:23ZengeLife Sciences Publications LtdeLife2050-084X2025-04-011410.7554/eLife.85599Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1William Hockeimer0https://orcid.org/0000-0002-2619-2528Ruo-Yah Lai1Maanasa Natrajan2William Snider3James J Knierim4https://orcid.org/0000-0002-1796-2930Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, United States; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United StatesKrieger Mind/Brain Institute, Johns Hopkins University, Baltimore, United StatesSolomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United StatesKrieger Mind/Brain Institute, Johns Hopkins University, Baltimore, United States; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United StatesKrieger Mind/Brain Institute, Johns Hopkins University, Baltimore, United States; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, United StatesThe hippocampus is believed to encode episodic memory by binding information about the content of experience within a spatiotemporal framework encoding the location and temporal context of that experience. Previous work implies a distinction between positional inputs to the hippocampus from upstream brain regions that provide information about an animal’s location and nonpositional inputs which provide information about the content of experience, both sensory and navigational. Here, we leverage the phenomenon of ‘place field repetition’ to better understand the functional dissociation between positional and nonpositional information encoded in CA1. Rats navigated freely on a novel maze consisting of linear segments arranged in a rectilinear, city-block configuration, which combined elements of open-field foraging and linear-track tasks. Unlike typical results in open-field foraging, place fields were directionally tuned on the maze, even though the animal’s behavior was not constrained to extended, one-dimensional (1D) trajectories. Repeating fields from the same cell tended to have the same directional preference when the fields were aligned along a linear corridor of the maze, but they showed uncorrelated directional preferences when they were unaligned across different corridors. Lastly, individual fields displayed complex time dynamics which resulted in the population activity changing gradually over the course of minutes. These temporal dynamics were evident across repeating fields of the same cell. These results demonstrate that the positional inputs that drive a cell to fire in similar locations across the maze can be behaviorally and temporally dissociated from the nonpositional inputs that alter the firing rates of the cell within its place fields, offering a potential mechanism to increase the flexibility of the system to encode episodic variables within a spatiotemporal framework provided by place cells.https://elifesciences.org/articles/85599hippocampusplace cellsepisodic-like memory
spellingShingle William Hockeimer
Ruo-Yah Lai
Maanasa Natrajan
William Snider
James J Knierim
Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1
eLife
hippocampus
place cells
episodic-like memory
title Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1
title_full Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1
title_fullStr Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1
title_full_unstemmed Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1
title_short Leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field CA1
title_sort leveraging place field repetition to understand positional versus nonpositional inputs to hippocampal field ca1
topic hippocampus
place cells
episodic-like memory
url https://elifesciences.org/articles/85599
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AT maanasanatrajan leveragingplacefieldrepetitiontounderstandpositionalversusnonpositionalinputstohippocampalfieldca1
AT williamsnider leveragingplacefieldrepetitiontounderstandpositionalversusnonpositionalinputstohippocampalfieldca1
AT jamesjknierim leveragingplacefieldrepetitiontounderstandpositionalversusnonpositionalinputstohippocampalfieldca1