The hippocampus converts dynamic entorhinal inputs into stable spatial maps

Cholvin, Thibault; Hainmueller, Thomas; Bartos, Marlene

doi:10.1016/j.neuron.2021.09.019

Cited by 37 publications

(72 citation statements)

References 101 publications

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“…One recent study used calcium imaging to examine the dynamics of DG granule cells during learning of a sensory-guided T-maze task, and found that place field stability correlated with behavioral performance (Shen et al, 2021). Alongside other DG imaging studies showing high cross-day similarity of spatial representations in well-trained animals (Hainmueller & Bartos, 2018; Cholvin et al, 2021), we can speculate about the mechanisms underlying the observed 7.8% reactivation in the Full-T group relative to Day 1. While the mice generalized learning well (Fig.…”

Section: Discussionsupporting

confidence: 55%

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Route-dependent spatial engram tagging in mouse dentate gyrus

Wilmerding

Kondratyev

Ramirez

et al. 2022

Preprint

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The dentate gyrus (DG) of hippocampus is hypothesized to act as a pattern separator that distinguishes between similar input patterns during memory formation and retrieval. Sparse ensembles of DG cells associated with learning and memory, i.e. engrams, have been labeled and manipulated to recall novel context memories. Functional studies of DG cell activity have demonstrated the spatial specificity and stability of DG cells during navigation. To reconcile how the DG contributes to separating global context as well as individual navigational routes, we trained mice to perform a delayed-non-match-to-position (DNMP) T-maze task and tagged DG neurons during performance of this task on a novel T-maze. The following day, mice navigated a second environment: the same T-maze, the same T-maze with one route permanently blocked but still visible, or a novel open field. First, we found that novelty and memory demand yielded larger engram ensemble size. Additionally, the degree of engram reactivation across days differed based on the traversal of maze routes, such that mice traversing only one arm had higher overlap than chance but less overlap than mice running the full two-route task. These differences could not be fully explained by behavioral differences across groups on the second day. Together, these results support the hypothesis that DG contributes to spatial navigation memory and that partially non-overlapping ensembles encode different routes within the context of different environments.

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Section: Discussionsupporting

confidence: 55%

“…Alongside other DG imaging studies showing high cross-day similarity of spatial representations in well-trained animals (Hainmueller & Bartos, 2018;Cholvin et al, 2021),…”

Section: Composition Of Sub-ensembles For Pattern Separationmentioning

confidence: 81%

Route-dependent spatial engram tagging in mouse dentate gyrus

Wilmerding

Kondratyev

Ramirez

et al. 2022

Preprint

View full text Add to dashboard Cite

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“…First, SST interneurons recieve strongly facilitiating excitatory synaptic input and have other membrane properties that allow these cells to be activated by a high-frequency burst from just one pre-synaptic neuron 69 , 70 . In hippocampus, gaining input from local principal neurons and losing ENTm input may help stabilize local network activity after TBI 71 . Second, muscarinic-mediated depolarization can produce prolonged spiking in SST interneurons 72 .…”

Section: Discussionmentioning

confidence: 99%

Brain-wide reconstruction of inhibitory circuits after traumatic brain injury

et al. 2022

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Despite the fundamental importance of understanding the brain’s wiring diagram, our knowledge of how neuronal connectivity is rewired by traumatic brain injury remains remarkably incomplete. Here we use cellular resolution whole-brain imaging to generate brain-wide maps of the input to inhibitory neurons in a mouse model of traumatic brain injury. We find that somatostatin interneurons are converted into hyperconnected hubs in multiple brain regions, with rich local network connections but diminished long-range inputs, even at areas not directly damaged. The loss of long-range input does not correlate with cell loss in distant brain regions. Interneurons transplanted into the injury site receive orthotopic local and long-range input, suggesting the machinery for establishing distant connections remains intact even after a severe injury. Our results uncover a potential strategy to sustain and optimize inhibition after traumatic brain injury that involves spatial reorganization of the direct inputs to inhibitory neurons across the brain.

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“…This navigation strategy is referred to as wayfinding (i.e., world-centered, allocentric navigation). The medial temporal lobe (MTL), especially the hippocampus, which is strongly interconnected with the entorhinal cortex (EC; Cholvin et al, 2021 ), is important for wayfinding (Maguire et al, 1998 ). The right hippocampus is more strongly associated with wayfinding than the left hippocampus (Maguire et al, 1998 ; Nedelska et al, 2012 ; Laczó et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Different Profiles of Spatial Navigation Deficits In Alzheimer’s Disease Biomarker-Positive Versus Biomarker-Negative Older Adults With Amnestic Mild Cognitive Impairment

Laczó

Martinkovič

Lerch

et al. 2022

Front. Aging Neurosci.

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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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The hippocampus converts dynamic entorhinal inputs into stable spatial maps

Cited by 37 publications

References 101 publications

Route-dependent spatial engram tagging in mouse dentate gyrus

Route-dependent spatial engram tagging in mouse dentate gyrus

Brain-wide reconstruction of inhibitory circuits after traumatic brain injury

Different Profiles of Spatial Navigation Deficits In Alzheimer’s Disease Biomarker-Positive Versus Biomarker-Negative Older Adults With Amnestic Mild Cognitive Impairment

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