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Issa JB, Radvansky BA, Xuan F, Dombeck DA. Lateral entorhinal cortex subpopulations represent experiential epochs surrounding reward. Nat Neurosci 2024; 27:536-546. [PMID: 38272968 PMCID: PMC11097142 DOI: 10.1038/s41593-023-01557-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024]
Abstract
During goal-directed navigation, 'what' information, describing the experiences occurring in periods surrounding a reward, can be combined with spatial 'where' information to guide behavior and form episodic memories. This integrative process likely occurs in the hippocampus, which receives spatial information from the medial entorhinal cortex; however, the source of the 'what' information is largely unknown. Here, we show that mouse lateral entorhinal cortex (LEC) represents key experiential epochs during reward-based navigation tasks. We discover separate populations of neurons that signal goal approach and goal departure and a third population signaling reward consumption. When reward location is moved, these populations immediately shift their respective representations of each experiential epoch relative to reward, while optogenetic inhibition of LEC disrupts learning the new reward location. Therefore, the LEC contains a stable code of experiential epochs surrounding and including reward consumption, providing reward-centric information to contextualize the spatial information carried by the medial entorhinal cortex.
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Affiliation(s)
- John B Issa
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Brad A Radvansky
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Feng Xuan
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Daniel A Dombeck
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
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2
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Bowler JC, Losonczy A. Direct cortical inputs to hippocampal area CA1 transmit complementary signals for goal-directed navigation. Neuron 2023; 111:4071-4085.e6. [PMID: 37816349 DOI: 10.1016/j.neuron.2023.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/14/2023] [Accepted: 09/13/2023] [Indexed: 10/12/2023]
Abstract
The subregions of the entorhinal cortex (EC) are conventionally thought to compute dichotomous representations for spatial processing, with the medial EC (MEC) providing a global spatial map and the lateral EC (LEC) encoding specific sensory details of experience. Yet, little is known about the specific types of information EC transmits downstream to the hippocampus. Here, we exploit in vivo sub-cellular imaging to record from EC axons in CA1 while mice perform navigational tasks in virtual reality (VR). We uncover distinct yet overlapping representations of task, location, and context in both MEC and LEC axons. MEC transmitted highly location- and context-specific codes; LEC inputs were biased by ongoing navigational goals. However, during tasks with reliable reward locations, the animals' position could be accurately decoded from either subregion. Our results revise the prevailing dogma about EC information processing, revealing novel ways spatial and non-spatial information is routed and combined upstream of the hippocampus.
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Affiliation(s)
- John C Bowler
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Doctoral Program in Neurobiology and Behavior, Columbia University, New York, NY 10027, USA.
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.
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3
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Aru J, Drüke M, Pikamäe J, Larkum ME. Mental navigation and the neural mechanisms of insight. Trends Neurosci 2023; 46:100-109. [PMID: 36462993 DOI: 10.1016/j.tins.2022.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 12/03/2022]
Abstract
How do new ideas come about? The central hypothesis presented here states that insights might happen during mental navigation and correspond to rapid plasticity at the cellular level. We highlight the differences between neocortical and hippocampal mechanisms of insight. We argue that the suddenness of insight can be related to the sudden emergence of place fields in the hippocampus. According to our hypothesis, insights are supported by a state of mind-wandering that can be tied to the process of combining knowledge pieces during sharp-wave ripples (SWRs). Our framework connects the dots between research on creativity, mental navigation, and specific synaptic plasticity mechanisms in the hippocampus.
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Affiliation(s)
- Jaan Aru
- Institute of Computer Science, University of Tartu, Tartu, Estonia.
| | - Moritz Drüke
- Institute of Biology, Humboldt University Berlin, Berlin, Germany
| | - Juhan Pikamäe
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Matthew E Larkum
- Institute of Biology, Humboldt University Berlin, Berlin, Germany; Neurocure Center for Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
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4
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Bilash OM, Chavlis S, Johnson CD, Poirazi P, Basu J. Lateral entorhinal cortex inputs modulate hippocampal dendritic excitability by recruiting a local disinhibitory microcircuit. Cell Rep 2023; 42:111962. [PMID: 36640337 DOI: 10.1016/j.celrep.2022.111962] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 10/31/2022] [Accepted: 12/20/2022] [Indexed: 01/06/2023] Open
Abstract
The lateral entorhinal cortex (LEC) provides multisensory information to the hippocampus, directly to the distal dendrites of CA1 pyramidal neurons. LEC neurons perform important functions for episodic memory processing, coding for contextually salient elements of an environment or experience. However, we know little about the functional circuit interactions between the LEC and the hippocampus. We combine functional circuit mapping and computational modeling to examine how long-range glutamatergic LEC projections modulate compartment-specific excitation-inhibition dynamics in hippocampal area CA1. We demonstrate that glutamatergic LEC inputs can drive local dendritic spikes in CA1 pyramidal neurons, aided by the recruitment of a disinhibitory VIP interneuron microcircuit. Our circuit mapping and modeling further reveal that LEC inputs also recruit CCK interneurons that may act as strong suppressors of dendritic spikes. These results highlight a cortically driven GABAergic microcircuit mechanism that gates nonlinear dendritic computations, which may support compartment-specific coding of multisensory contextual features within the hippocampus.
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Affiliation(s)
- Olesia M Bilash
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Spyridon Chavlis
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete 70013, Greece
| | - Cara D Johnson
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete 70013, Greece.
| | - Jayeeta Basu
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA; Department of Psychiatry, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA.
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5
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Castegnaro A, Howett D, Li A, Harding E, Chan D, Burgess N, King J. Assessing mild cognitive impairment using object-location memory in immersive virtual environments. Hippocampus 2022; 32:660-678. [PMID: 35916343 PMCID: PMC9543035 DOI: 10.1002/hipo.23458] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 06/24/2022] [Accepted: 07/16/2022] [Indexed: 11/12/2022]
Abstract
Pathological changes in the medial temporal lobe (MTL) are found in the early stages of Alzheimer's disease (AD) and aging. The earliest pathological accumulation of tau colocalizes with the areas of the MTL involved in object processing as part of a wider anterolateral network. Here, we sought to assess the diagnostic potential of memory for object locations in iVR environments in individuals at high risk of AD dementia (amnestic mild cognitive impairment [aMCI] n = 23) as compared to age-related cognitive decline. Consistent with our primary hypothesis that early AD would be associated with impaired object location, aMCI patients exhibited impaired spatial feature binding. Compared to both older (n = 24) and younger (n = 53) controls, aMCI patients, recalled object locations with significantly less accuracy (p < .001), with a trend toward an impaired identification of the object's correct context (p = .05). Importantly, these findings were not explained by deficits in object recognition (p = .6). These deficits differentiated aMCI from controls with greater accuracy (AUC = 0.89) than the standard neuropsychological tests. Within the aMCI group, 16 had CSF biomarkers indicative of their likely AD status (MCI+ n = 9 vs. MCI- n = 7). MCI+ showed lower accuracy in the object-context association than MCI- (p = .03) suggesting a selective deficit in object-context binding postulated to be associated with anterior-temporal areas. MRI volumetric analysis across healthy older participants and aMCI revealed that test performance positively correlates with lateral entorhinal cortex volumes (p < .05) and hippocampus volumes (p < .01), consistent with their hypothesized role in binding contextual and spatial information with object identity. Our results indicate that tests relying on the anterolateral object processing stream, and in particular requiring successful binding of an object with spatial information, may aid detection of pre-dementia AD due to the underlying early spread of tau pathology.
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Affiliation(s)
- Andrea Castegnaro
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
| | - David Howett
- School of Psychological ScienceUniversity of BristolBristolUK
| | - Adrienne Li
- Department of PsychologyYork UniversityTorontoOntarioCanada
| | - Elizabeth Harding
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
| | - Dennis Chan
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
| | - Neil Burgess
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
| | - John King
- Department of Clinical, Educational and Health PsychologyUniversity College LondonLondonUK
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Laczó M, Martinkovic L, Lerch O, Wiener JM, Kalinova J, Matuskova V, Nedelska Z, Vyhnalek M, Hort J, Laczó J. Different Profiles of Spatial Navigation Deficits In Alzheimer’s Disease Biomarker-Positive Versus Biomarker-Negative Older Adults With Amnestic Mild Cognitive Impairment. Front Aging Neurosci 2022; 14:886778. [PMID: 35721017 PMCID: PMC9201637 DOI: 10.3389/fnagi.2022.886778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/29/2022] [Indexed: 12/22/2022] Open
Abstract
BackgroundSpatial navigation impairment is a promising cognitive marker of Alzheimer’s disease (AD) that can reflect the underlying pathology.ObjectivesWe assessed spatial navigation performance in AD biomarker positive older adults with amnestic mild cognitive impairment (AD aMCI) vs. those AD biomarker negative (non-AD aMCI), and examined associations between navigation performance, MRI measures of brain atrophy, and cerebrospinal fluid (CSF) biomarkers.MethodsA total of 122 participants with AD aMCI (n = 33), non-AD aMCI (n = 31), mild AD dementia (n = 28), and 30 cognitively normal older adults (CN) underwent cognitive assessment, brain MRI (n = 100 had high-quality images for volumetric analysis) and three virtual navigation tasks focused on route learning (body-centered navigation), wayfinding (world-centered navigation) and perspective taking/wayfinding. Cognitively impaired participants underwent CSF biomarker assessment [amyloid-β1–42, total tau, and phosphorylated tau181 (p-tau181)] and amyloid PET imaging (n = 47 and n = 45, respectively), with a subset having both (n = 19).ResultsIn route learning, AD aMCI performed worse than non-AD aMCI (p < 0.001), who performed similarly to CN. In wayfinding, aMCI participants performed worse than CN (both p ≤ 0.009) and AD aMCI performed worse than non-AD aMCI in the second task session (p = 0.032). In perspective taking/wayfinding, aMCI participants performed worse than CN (both p ≤ 0.001). AD aMCI and non-AD aMCI did not differ in conventional cognitive tests. Route learning was associated with parietal thickness and amyloid-β1–42, wayfinding was associated with posterior medial temporal lobe (MTL) volume and p-tau181 and perspective taking/wayfinding was correlated with MRI measures of several brain regions and all CSF biomarkers.ConclusionAD biomarker positive and negative older adults with aMCI had different profiles of spatial navigation deficits that were associated with posterior MTL and parietal atrophy and reflected AD pathology.
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Affiliation(s)
- Martina Laczó
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
| | - Lukas Martinkovic
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
| | - Ondrej Lerch
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
- International Clinical Research Center, St. Anne’s University Hospital Brno, Brno, Czechia
| | - Jan M. Wiener
- Department of Psychology, Ageing and Dementia Research Centre, Bournemouth University, Poole, United Kingdom
| | - Jana Kalinova
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
| | - Veronika Matuskova
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
- International Clinical Research Center, St. Anne’s University Hospital Brno, Brno, Czechia
| | - Zuzana Nedelska
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
- International Clinical Research Center, St. Anne’s University Hospital Brno, Brno, Czechia
| | - Martin Vyhnalek
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
- International Clinical Research Center, St. Anne’s University Hospital Brno, Brno, Czechia
| | - Jakub Hort
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
- International Clinical Research Center, St. Anne’s University Hospital Brno, Brno, Czechia
| | - Jan Laczó
- Memory Clinic, Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czechia
- International Clinical Research Center, St. Anne’s University Hospital Brno, Brno, Czechia
- *Correspondence: Jan Laczó
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Persson BM, Ambrozova V, Duncan S, Wood ER, O’Connor AR, Ainge JA. Lateral entorhinal cortex lesions impair odor-context associative memory in male rats. J Neurosci Res 2022; 100:1030-1046. [PMID: 35187710 PMCID: PMC9302644 DOI: 10.1002/jnr.25027] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/14/2023]
Abstract
Lateral entorhinal cortex (LEC) has been hypothesized to process nonspatial, item information that is combined with spatial information from medial entorhinal cortex to form episodic memories within the hippocampus. Recent studies, however, have demonstrated that LEC has a role in integrating features of episodic memory prior to the hippocampus. While the precise role of LEC is still unclear, anatomical studies show that LEC is ideally placed to be a hub integrating multisensory information. The current study tests whether the role of LEC in integrating information extends to long-term multimodal item-context associations. In Experiment 1, male rats were trained on a context-dependent odor discrimination task, where two different contexts served as the cue to the correct odor. Rats were pretrained on the task and then received either bilateral excitotoxic LEC or sham lesions. Following surgery, rats were tested on the previously learned odor-context associations. Control rats showed good memory for the previously learned association but rats with LEC lesions showed significantly impaired performance relative to both their own presurgery performance and to control rats. Experiment 2 went on to test whether impairments in Experiment 1 were the result of LEC lesions impairing either odor or context memory retention alone. Male rats were trained on simple odor and context discrimination tasks that did not require integration of features to solve. Following surgery, both LEC and control rats showed good memory for previously learned odors and contexts. These data show that LEC is critical for long-term odor-context associative memory.
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Affiliation(s)
- Bjorn M. Persson
- School of Psychology & NeuroscienceUniversity of St AndrewsSt AndrewsUK
| | | | - Stephen Duncan
- School of Psychology & NeuroscienceUniversity of St AndrewsSt AndrewsUK
| | - Emma R. Wood
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
| | - Akira R. O’Connor
- School of Psychology & NeuroscienceUniversity of St AndrewsSt AndrewsUK
| | - James A. Ainge
- School of Psychology & NeuroscienceUniversity of St AndrewsSt AndrewsUK
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8
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Taniguchi A, Fukawa A, Yamakawa H. Hippocampal formation-inspired probabilistic generative model. Neural Netw 2022; 151:317-335. [DOI: 10.1016/j.neunet.2022.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 03/09/2022] [Accepted: 04/03/2022] [Indexed: 11/25/2022]
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9
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Borcuk C, Héraud C, Herbeaux K, Diringer M, Panzer É, Scuto J, Hashimoto S, Saido TC, Saito T, Goutagny R, Battaglia D, Mathis C. Early memory deficits and extensive brain network disorganization in the AppNL-F/MAPT double knock-in mouse model of familial Alzheimer's disease. AGING BRAIN 2022; 2:100042. [PMID: 36908877 PMCID: PMC9997176 DOI: 10.1016/j.nbas.2022.100042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 10/18/2022] Open
Abstract
A critical challenge in current research on Alzheimer's disease (AD) is to clarify the relationship between network dysfunction and the emergence of subtle memory deficits in itspreclinical stage. The AppNL-F/MAPT double knock-in (dKI) model with humanized β-amyloid peptide (Aβ) and tau was used to investigate both memory and network dysfunctions at an early stage. Young male dKI mice (2 to 6 months) were tested in three tasks taxing different aspects of recognition memory affected in preclinical AD. An early deficit first appeared in the object-place association task at the age of 4 months, when increased levels of β-CTF and Aβ were detected in both the hippocampus and the medial temporal cortex, and tau pathology was found only in the medial temporal cortex. Object-place task-dependent c-Fos activation was then analyzed in 22 subregions across the medial prefrontal cortex, claustrum, retrosplenial cortex, and medial temporal lobe. Increased c-Fos activation was detected in the entorhinal cortex and the claustrum of dKI mice. During recall, network efficiency was reduced across cingulate regions with a major disruption of information flow through the retrosplenial cortex. Our findings suggest that early perirhinal-entorhinal pathology is associated with abnormal activity which may spread to downstream regions such as the claustrum, the medial prefrontal cortex and ultimately the key retrosplenial hub which relays information from frontal to temporal lobes. The similarity between our findings and those reported in preclinical stages of AD suggests that the AppNL-F/MAPT dKI model has a high potential for providing key insights into preclinical AD.
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Key Words
- AD, Alzheimer’s disease
- ADAD, autosomal dominant Alzheimer’s disease
- Associative memory
- CLA, claustrum
- Claustrum
- DMN, default mode network
- EI, exploration index
- FC, functional connectivity
- Functional connectivity
- MI, Memory index
- MTC, medial temporal cortex
- MTL, medial temporal lobe
- Medial temporal cortex
- NOR, novel object recognition
- OL, Object location
- OP, object-place
- PS, Pattern Separation
- Preclinical Alzheimer disease
- Retrosplenial cortex
- aMCI, amnestic mild cognitive impairment
- amyloid beta, Aβ
- dKI, AppNL-F/MAPT double knock-in
- ptau Thr 181, Thr181phosphorylated tau protein
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Affiliation(s)
- Christopher Borcuk
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Céline Héraud
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Karine Herbeaux
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Margot Diringer
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Élodie Panzer
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Jil Scuto
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Shoko Hashimoto
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Romain Goutagny
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
| | - Demian Battaglia
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France.,University of Strasbourg Institute for Advanced Studies (USIAS), F-67000 Strasbourg, France.,Université d'Aix-Marseille, Inserm, Institut de Neurosciences des Systèmes (INS) UMR_S 1106, F-13005 Marseille, France
| | - Chantal Mathis
- Université de Strasbourg, CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA) UMR 7364, F-67000 Strasbourg, France
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Vandrey B, Duncan S, Ainge JA. Object and object-memory representations across the proximodistal axis of CA1. Hippocampus 2021; 31:881-896. [PMID: 33942429 DOI: 10.1002/hipo.23331] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 03/11/2021] [Accepted: 03/28/2021] [Indexed: 11/07/2022]
Abstract
Episodic memory requires information about objects to be integrated into a spatial framework. Place cells in the hippocampus encode spatial representations of objects that could be generated through signaling from the entorhinal cortex. Projections from lateral (LEC) and medial entorhinal cortex (MEC) to the hippocampus terminate in distal and proximal CA1, respectively. We recorded place cells in distal and proximal CA1 as rats explored an environment that contained objects. Place cells in distal CA1 demonstrated higher measures of spatial tuning, stability, and closer proximity of place fields to objects. Furthermore, remapping to object displacement was modulated by place field proximity to objects in distal, but not proximal CA1. Finally, representations of previous object locations were closer to those locations in distal CA1 than proximal CA1. Our data suggest that in cue-rich environments, LEC inputs to the hippocampus support spatial representations with higher spatial tuning, closer proximity to objects, and greater stability than those receiving inputs from MEC. This is consistent with functional segregation in the entorhinal-hippocampal circuits underlying object-place memory.
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Affiliation(s)
- Brianna Vandrey
- University of St Andrews, School of Psychology and Neuroscience, St Andrews, Fife, UK
- University of Edinburgh, Centre for Discovery Brain Sciences, Edinburgh, EH8 9XD, UK
| | - Stephen Duncan
- University of St Andrews, School of Psychology and Neuroscience, St Andrews, Fife, UK
| | - James A Ainge
- University of St Andrews, School of Psychology and Neuroscience, St Andrews, Fife, UK
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