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Wirtshafter HS, Quan M, Wilson MA. Dissociating Behavior and Spatial Working Memory Demands Using an H Maze. Bio Protoc 2021; 11:e3947. [PMID: 33796621 DOI: 10.21769/bioprotoc.3947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 11/02/2022] Open
Abstract
The development of mazes for animal experiments has allowed for the investigation of cognitive maps and place cells, spatial working memory, naturalistic navigation, perseverance, exploration, and choice and motivated behavior. However, many mazes, such as the T maze, currently developed to test learning and memory, do not distinguish temporally and spatially between the encoding and recall periods, which makes it difficult to study these stages separately when analyzing animal behavior and electrophysiology. Other mazes, such as the radial maze, rely on single visits to portions of the maze, making maze coverage sparse for place cell and electrophysiology experiments. In this protocol, we present instructions for building and training an animal on a spatial appetitive choice task on a low-cost double-sided T (or H) maze. This maze has several advantages over the traditional T maze and radial mazes. This maze is unique in that it temporally and directionally dissociates the memory encoding and retrieval periods, while requiring the same behaviors of the animal during both periods. This design allows for independent investigation of brain mechanisms, such as cross-region theta coordination, during memory encoding and retrieval, while at least partially dissociating these stages from behavior. This maze has been previously used in our laboratory to investigate cell firing, single-region local field potential (LFP) patterns, and cross region LFP coherence in the hippocampus, lateral septum, prefrontal cortex, and ventral tegmental area, as well as to investigate the effects of hippocampal theta perturbations on task performance.
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Affiliation(s)
- Hannah S Wirtshafter
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.,Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Moqing Quan
- Wellesley College, 106 Central St, Wellesley, MA 02481, USA
| | - Matthew A Wilson
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.,Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Duvelle É, Grieves RM, Hok V, Poucet B, Arleo A, Jeffery KJ, Save E. Insensitivity of Place Cells to the Value of Spatial Goals in a Two-Choice Flexible Navigation Task. J Neurosci 2019; 39:2522-2541. [PMID: 30696727 PMCID: PMC6435828 DOI: 10.1523/jneurosci.1578-18.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 01/28/2023] Open
Abstract
Hippocampal place cells show position-specific activity thought to reflect a self-localization signal. Several reports also point to some form of goal encoding by place cells. We investigated this by asking whether they also encode the value of spatial goals, which is crucial information for optimizing goal-directed navigation. We used a continuous place navigation task in which male rats navigate to one of two (freely chosen) unmarked locations and wait, triggering the release of reward, which is then located and consumed elsewhere. This allows sampling of place fields and dissociates spatial goal from reward consumption. The two goals varied in the amount of reward provided, allowing assessment of whether the rats factored goal value into their navigational choice and of possible neural correlates of this value. Rats successfully learned the task, indicating goal localization, and they preferred higher-value goals, indicating processing of goal value. Replicating previous findings, there was goal-related activity in the out-of-field firing of CA1 place cells, with a ramping-up of firing rate during the waiting period, but no general overrepresentation of goals by place fields, an observation that we extended to CA3 place cells. Importantly, place cells were not modulated by goal value. This suggests that dorsal hippocampal place cells encode space independently of its associated value despite the effect of that value on spatial behavior. Our findings are consistent with a model of place cells in which they provide a spontaneously constructed value-free spatial representation rather than encoding other navigationally relevant but nonspatial information.SIGNIFICANCE STATEMENT We investigated whether hippocampal place cells, which compute a self-localization signal, also encode the relative value of places, which is essential information for optimal navigation. When choosing between two spatial goals of different value, rats preferred the higher-value goal. We saw out-of-field goal firing in place cells, replicating previous observations that the cells are influenced by the goal, but their activity was not modulated by the value of these goals. Our results suggest that place cells do not encode all of the navigationally relevant aspects of a place, but instead form a value-free "map" that links to such aspects in other parts of the brain.
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Affiliation(s)
- Éléonore Duvelle
- Aix Marseille University, Centre National de la Recherche Scientifique (CNRS), Laboratory of Cognitive Neuroscience, Marseille, France
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France, and
- Institute of Behavioural Neuroscience, Division of Psychology and Language Sciences, University College London, London WC1H 0AP, United Kingdom
| | - Roddy M Grieves
- Institute of Behavioural Neuroscience, Division of Psychology and Language Sciences, University College London, London WC1H 0AP, United Kingdom
| | - Vincent Hok
- Aix Marseille University, Centre National de la Recherche Scientifique (CNRS), Laboratory of Cognitive Neuroscience, Marseille, France
| | - Bruno Poucet
- Aix Marseille University, Centre National de la Recherche Scientifique (CNRS), Laboratory of Cognitive Neuroscience, Marseille, France
| | - Angelo Arleo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France, and
| | - Kate J Jeffery
- Institute of Behavioural Neuroscience, Division of Psychology and Language Sciences, University College London, London WC1H 0AP, United Kingdom
| | - Etienne Save
- Aix Marseille University, Centre National de la Recherche Scientifique (CNRS), Laboratory of Cognitive Neuroscience, Marseille, France,
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