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Alfaro-Ruiz R, Martín-Belmonte A, Aguado C, Moreno-Martínez AE, Fukazawa Y, Luján R. Selective disruption of synaptic NMDA receptors of the hippocampal trisynaptic circuit in Aβ pathology. Biol Res 2024; 57:56. [PMID: 39175009 PMCID: PMC11340147 DOI: 10.1186/s40659-024-00537-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 08/06/2024] [Indexed: 08/24/2024] Open
Abstract
Synaptic dysfunction is an early feature in Alzheimer's disease (AD) pathogenesis and a major morphological correlate of memory deficits. Given the main synaptic location of N-methyl-D-aspartate receptors (NMDARs), their dysregulation has been implicated in these pathological effects. Here, to detect possible alterations in the expression and synaptic localisation of the GluN1 subunit in the brain of amyloidogenic APP/PS1 mice, we employed histoblot and SDS-digested freeze-fracture replica labelling (SDS-FRL) techniques. Histoblots showed that GluN1 expression was significantly reduced in the hippocampus in a layer-dependent manner, in the cortex and the caudate putamen of APP/PS1 transgenic mice at 12 months of age but was unaltered at 1 and 6 months. Using quantitative SDS-FRL, we unravelled the molecular organisation of GluN1 in seven excitatory synapse populations at a high spatial resolution in the CA1 and CA3 fields and the DG of the hippocampus in 12-month-old APP/PS1 mice. In the CA1 field, the labelling density for GluN1 in the excitatory synapses established on spines and interneurons, was significantly reduced in APP/PS1 mice compared to age-matched wild-type mice in the stratum lacunosum-moleculare but unaltered in the stratum radiatum. In the CA3 field, synaptic GluN1 was reduced in mossy fibre-CA3 pyramidal cell synapses but unaltered in the A/C-CA3 pyramidal cell synapses. In the DG, the density of GluN1 in granule cell-perforant pathway synapses was reduced in APP/PS1 mice. Altogether, our findings provide evidence of specific alterations of synaptic GluN1 in the trisynaptic circuit of the hippocampus in Aβ pathology. This differential vulnerability in the disruption of NMDARs may be involved in the mechanisms causing abnormal network activity of the hippocampal circuit and cognitive impairment characteristic of APP/PS1 mice.
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Affiliation(s)
- Rocio Alfaro-Ruiz
- Synaptic Structure Laboratory, Departamento de Ciencias Médicas, Facultad de Medicina, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, Albacete, 02008, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Alejandro Martín-Belmonte
- Synaptic Structure Laboratory, Departamento de Ciencias Médicas, Facultad de Medicina, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, Albacete, 02008, Spain
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, 08907, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, L'Hospitalet de Llobregat, 08907, Spain
| | - Carolina Aguado
- Synaptic Structure Laboratory, Departamento de Ciencias Médicas, Facultad de Medicina, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, Albacete, 02008, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Ana Esther Moreno-Martínez
- Synaptic Structure Laboratory, Departamento de Ciencias Médicas, Facultad de Medicina, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, Albacete, 02008, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Yugo Fukazawa
- Division of Brain Structure and Function, Faculty of Medical Science, University of Fukui, Fukui, Japan
- Life Science Innovation Center, University of Fukui, Fukui, Japan
| | - Rafael Luján
- Synaptic Structure Laboratory, Departamento de Ciencias Médicas, Facultad de Medicina, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, Albacete, 02008, Spain.
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain.
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Signal B, Phipps AJ, Giles KA, Huskins SN, Mercer TR, Robinson MD, Woodhouse A, Taberlay PC. Ageing-Related Changes to H3K4me3, H3K27ac, and H3K27me3 in Purified Mouse Neurons. Cells 2024; 13:1393. [PMID: 39195281 DOI: 10.3390/cells13161393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 08/19/2024] [Accepted: 08/19/2024] [Indexed: 08/29/2024] Open
Abstract
Neurons are central to lifelong learning and memory, but ageing disrupts their morphology and function, leading to cognitive decline. Although epigenetic mechanisms are known to play crucial roles in learning and memory, neuron-specific genome-wide epigenetic maps into old age remain scarce, often being limited to whole-brain homogenates and confounded by glial cells. Here, we mapped H3K4me3, H3K27ac, and H3K27me3 in mouse neurons across their lifespan. This revealed stable H3K4me3 and global losses of H3K27ac and H3K27me3 into old age. We observed patterns of synaptic function gene deactivation, regulated through the loss of the active mark H3K27ac, but not H3K4me3. Alongside this, embryonic development loci lost repressive H3K27me3 in old age. This suggests a loss of a highly refined neuronal cellular identity linked to global chromatin reconfiguration. Collectively, these findings indicate a key role for epigenetic regulation in neurons that is inextricably linked with ageing.
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Affiliation(s)
- Brandon Signal
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Andrew J Phipps
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Katherine A Giles
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
- Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2145, Australia
| | - Shannon N Huskins
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Timothy R Mercer
- Australian Institute for Bioengineering and Nanotechnology, Corner College and Cooper Roads, Brisbane, QLD 4072, Australia
| | - Mark D Robinson
- SIB Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Adele Woodhouse
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Phillippa C Taberlay
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
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Fan B, Lin J, Luo Q, Liao W, Hao C. Enriched Environment Inhibits Neurotoxic Reactive Astrocytes via JAK2-STAT3 to Promote Glutamatergic Synaptogenesis and Cognitive Improvement in Chronic Cerebral Hypoperfusion Rats. Neurotox Res 2024; 42:22. [PMID: 38564082 DOI: 10.1007/s12640-024-00704-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2024] [Indexed: 04/04/2024]
Abstract
Chronic cerebral hypoperfusion (CCH) is a primary contributor to cognitive decline in the elderly. Enriched environment (EE) is proved to improve cognitive function. However, mechanisms involved remain unclear. The purpose of the study was exploring the mechanisms of EE in alleviating cognitive deficit in rats with CCH. To create a rat model of CCH, 2-vessel occlusion (2-VO) surgery was performed. All rats lived in standard or enriched environments for 4 weeks. Cognitive function was assessed using the novel object recognition test and Morris water maze test. The protein levels of glutamatergic synapses, neurotoxic reactive astrocytes, reactive microglia, and JAK2-STAT3 signaling pathway were measured using Western blot. The mRNA levels of synaptic regulatory factors, C1q, TNF-α, and IL-1α were identified using quantitative PCR. Immunofluorescence was used to detect glutamatergic synapses, neurotoxic reactive astrocytes, and reactive microglia, as well as the expression of p-STAT3 in astrocytes in the hippocampus. The results demonstrated that the EE mitigated cognitive impairment in rats with CCH and enhanced glutamatergic synaptogenesis. EE also inhibited the activation of neurotoxic reactive astrocytes. Moreover, EE downregulated microglial activation, levels of C1q, TNF-α and IL-1α and phosphorylation of JAK2 and STAT3. Our results suggest that inhibition of neurotoxic reactive astrocytes may be one of the mechanisms by which EE promotes glutamatergic synaptogenesis and improves cognitive function in rats with CCH. The downregulation of reactive microglia and JAK2-STAT3 signaling pathway may be involved in this process.
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Affiliation(s)
- Bin Fan
- Department of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Junbin Lin
- Department of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Qihang Luo
- Department of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Weijing Liao
- Department of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
| | - Chizi Hao
- Department of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
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4
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Awasthi R, Yuan Q, Barkai E. Reversing Aging: Decline in Complex Olfactory Learning Can be Rectified by Restoring Intrinsic Plasticity of Hippocampal CA1 Pyramidal Neurons. Adv Biol (Weinh) 2024; 8:e2300323. [PMID: 38145360 DOI: 10.1002/adbi.202300323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/24/2023] [Indexed: 12/26/2023]
Abstract
The acquisition of complex rules requires modifications in intrinsic plasticity of excitatory neurons within relevant brain areas. Olfactory discrimination (OD) rule learning occludes slow calcium-dependent potassium current (sIAHP ) in piriform cortex (PC) pyramidal neurons, which increases their intrinsic neuronal excitability. Similar learning-induced sIAHP changes are demonstrated in hippocampal CA1. The shutdown of sIAHP is mediated by the metabotropic activation of the kainate subtype glutamatergic receptor, GluK2. Here, the duration of training required for OD rule learning increased significantly as the mice matured and aged is first shown, which appears earlier in 5xFAD mice. At the cellular biophysical level, aging is accompanied by reduction in the post-burst AHP in these neurons, while neuronal excitability remains stable. This is in contrast to aging CA1 neurons that exhibit enhanced post-burst AHPs in previous reports. Kainate reduces post-burst AHP in adults, but not in aged PC neurons, whereas it reduces post-burst AHPs in hippocampal CA1 pyramidal neurons of both young and aged mice. Overexpression of GluK2 in CA1 neurons restores OD learning capabilities in aged wild-type and 5xFAD mice, to a level comparable to young adults. Activation of GluK2 receptors in selectively vulnerable neurons can prevent aging-related cognitive decline is suggested.
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Affiliation(s)
- Richa Awasthi
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
| | - Qi Yuan
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, A1B 3V6, Canada
| | - Edi Barkai
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
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Wirtshafter HS, Disterhoft JF. Place cells are nonrandomly clustered by field location in CA1 hippocampus. Hippocampus 2023; 33:65-84. [PMID: 36519700 PMCID: PMC9877199 DOI: 10.1002/hipo.23489] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 11/26/2022] [Accepted: 12/04/2022] [Indexed: 12/23/2022]
Abstract
A challenge in both modern and historic neuroscience has been achieving an understanding of neuron circuits, and determining the computational and organizational principles that underlie these circuits. Deeper understanding of the organization of brain circuits and cell types, including in the hippocampus, is required for advances in behavioral and cognitive neuroscience, as well as for understanding principles governing brain development and evolution. In this manuscript, we pioneer a new method to analyze the spatial clustering of active neurons in the hippocampus. We use calcium imaging and a rewarded navigation task to record from 100 s of place cells in the CA1 of freely moving rats. We then use statistical techniques developed for and in widespread use in geographic mapping studies, global Moran's I, and local Moran's I to demonstrate that cells that code for similar spatial locations tend to form small spatial clusters. We present evidence that this clustering is not the result of artifacts from calcium imaging, and show that these clusters are primarily formed by cells that have place fields around previously rewarded locations. We go on to show that, although cells with similar place fields tend to form clusters, there is no obvious topographic mapping of environmental location onto the hippocampus, such as seen in the visual cortex. Insights into hippocampal organization, as in this study, can elucidate mechanisms underlying motivational behaviors, spatial navigation, and memory formation.
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Affiliation(s)
- Hannah S. Wirtshafter
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, 310 E. Superior St., Morton 5-660, Chicago, IL 60611
| | - John F. Disterhoft
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, 310 E. Superior St., Morton 5-660, Chicago, IL 60611
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6
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Intrinsic Excitability in Layer IV-VI Anterior Insula to Basolateral Amygdala Projection Neurons Correlates with the Confidence of Taste Valence Encoding. eNeuro 2023; 10:ENEURO.0302-22.2022. [PMID: 36635250 PMCID: PMC9850927 DOI: 10.1523/eneuro.0302-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/01/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022] Open
Abstract
Avoiding potentially harmful, and consuming safe food is crucial for the survival of living organisms. However, the perceived valence of sensory information can change following conflicting experiences. Pleasurability and aversiveness are two crucial parameters defining the perceived valence of a taste and can be impacted by novelty. Importantly, the ability of a given taste to serve as the conditioned stimulus (CS) in conditioned taste aversion (CTA) is dependent on its valence. Activity in anterior insula (aIC) Layer IV-VI pyramidal neurons projecting to the basolateral amygdala (BLA) is correlated with and necessary for CTA learning and retrieval, as well as the expression of neophobia toward novel tastants, but not learning taste familiarity. Yet, the cellular mechanisms underlying the updating of taste valence representation in this specific pathway are poorly understood. Here, using retrograde viral tracing and whole-cell patch-clamp electrophysiology in trained mice, we demonstrate that the intrinsic properties of deep-lying Layer IV-VI, but not superficial Layer I-III aIC-BLA neurons, are differentially modulated by both novelty and valence, reflecting the subjective predictability of taste valence arising from prior experience. These correlative changes in the profile of intrinsic properties of LIV-VI aIC-BLA neurons were detectable following both simple taste experiences, as well as following memory retrieval, extinction learning, and reinstatement.
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7
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Chowdhury A, Luchetti A, Fernandes G, Filho DA, Kastellakis G, Tzilivaki A, Ramirez EM, Tran MY, Poirazi P, Silva AJ. A locus coeruleus-dorsal CA1 dopaminergic circuit modulates memory linking. Neuron 2022; 110:3374-3388.e8. [PMID: 36041433 PMCID: PMC10508214 DOI: 10.1016/j.neuron.2022.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/07/2022] [Accepted: 07/31/2022] [Indexed: 11/20/2022]
Abstract
Individual memories are often linked so that the recall of one triggers the recall of another. For example, contextual memories acquired close in time can be linked, and this is known to depend on a temporary increase in excitability that drives the overlap between dorsal CA1 (dCA1) hippocampal ensembles that encode the linked memories. Here, we show that locus coeruleus (LC) cells projecting to dCA1 have a key permissive role in contextual memory linking, without affecting contextual memory formation, and that this effect is mediated by dopamine. Additionally, we found that LC-to-dCA1-projecting neurons modulate the excitability of dCA1 neurons and the extent of overlap between dCA1 memory ensembles as well as the stability of coactivity patterns within these ensembles. This discovery of a neuromodulatory system that specifically affects memory linking without affecting memory formation reveals a fundamental separation between the brain mechanisms modulating these two distinct processes.
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Affiliation(s)
- Ananya Chowdhury
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Alessandro Luchetti
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Giselle Fernandes
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Daniel Almeida Filho
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - George Kastellakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas (FORTH), Vassilica Vouton, PO Box 1527, GR 711 10 Heraklion, Crete, Greece
| | - Alexandra Tzilivaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas (FORTH), Vassilica Vouton, PO Box 1527, GR 711 10 Heraklion, Crete, Greece
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health Charitéplatz 1, 10117 Berlin Germany
- Einstein Center for Neurosciences Berlin Charitéplatz 1, 10117 Berlin Germany
- Neurocure Cluster of Excellence Charitéplatz 1, 10117 Berlin, Germany
| | - Erica M Ramirez
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Mary Y Tran
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas (FORTH), Vassilica Vouton, PO Box 1527, GR 711 10 Heraklion, Crete, Greece
| | - Alcino J Silva
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
- Lead contact
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Keifer J. Emergence of In Vitro Preparations and Their Contribution to Understanding the Neural Control of Behavior in Vertebrates. J Neurophysiol 2022; 128:511-526. [PMID: 35946803 DOI: 10.1152/jn.00142.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One of the longstanding goals of the field of neuroscience is to understand the neural control of behavior in both invertebrate and vertebrate species. A series of early discoveries showed that certain motor patterns like locomotion could be generated by neuronal circuits without sensory feedback or descending control systems. These were called fictitious, or "fictive", motor programs because they could be expressed by neurons in the absence of movement. This finding lead investigators to isolate central nervous system tissue and maintain it in a dish in vitro to better study mechanisms of motor pattern generation. A period of rapid development of in vitro preparations from invertebrate species that could generate fictive motor programs from the activity of central pattern generating circuits (CPGs) emerged that was gradually followed by the introduction of such preparations from vertebrates. Here, I will review some of the notable in vitropreparations from both mammalian and non-mammalian vertebrate species developed to study the neural circuits underlying a variety of complex behaviors. This approach has been instrumental in delineating not only the cellular substrates underlying locomotion, respiration, scratching, and other behaviors, but also mechanisms underlying the modifiability of motor pathways through synaptic plasticity. In vitro preparations have had a significant impact on the field of motor systems neuroscience and the expansion of our understanding of how nervous systems control behavior. The field is ready for further advancement of this approach to explore neural substrates for variations in behavior generated by social and seasonal context, and the environment.
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Affiliation(s)
- Joyce Keifer
- Neuroscience Group, Basic Biomedical Sciences, University of South Dakota Sanford School of Medicine, Vermillion, SD, United States
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9
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Gramuntell Y, Klimczak P, Coviello S, Perez-Rando M, Nacher J. Effects of Aging on the Structure and Expression of NMDA Receptors of Somatostatin Expressing Neurons in the Mouse Hippocampus. Front Aging Neurosci 2022; 13:782737. [PMID: 35002680 PMCID: PMC8733323 DOI: 10.3389/fnagi.2021.782737] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
Changes in the physiology, neurochemistry and structure of neurons, particularly of their dendritic spines, are thought to be crucial players in age-related cognitive decline. One of the most studied brain structures affected by aging is the hippocampus, known to be involved in different essential cognitive processes. While the aging-associated quantitative changes in dendritic spines of hippocampal pyramidal cells have already been studied, the relationship between aging and the structural dynamics of hippocampal interneurons remains relatively unknown. Spines are not a frequent feature in cortical inhibitory neurons, but these postsynaptic structures are abundant in a subpopulation of somatostatin expressing interneurons, particularly in oriens-lacunosum moleculare (O-LM) cells in the hippocampal CA1. Previous studies from our laboratory have shown that the spines of these interneurons are highly plastic and influenced by NMDA receptor manipulation. Thus, in the present study, we have investigated the impact of aging on this interneuronal subpopulation. The analyses were performed in 3−, 9−, and 16-month-old GIN mice, a strain in which somatostatin positive interneurons express GFP. We studied the changes in the density of dendritic spines, en passant boutons, and the expression of NMDA receptors (GluN1 and GluN2B) using confocal microscopy and image analysis. We observed a significant decrease in dendritic spine density in 9-month-old animals when compared with 3-month-old animals. We also observed a decrease in the expression of the GluN2B subunit in O-LM cells, but not of that of GluN1, during aging. These results will constitute the basis for more advanced studies of the structure and connectivity of interneurons during aging and their contribution to cognitive decline.
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Affiliation(s)
- Yaiza Gramuntell
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | - Patrycja Klimczak
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Simona Coviello
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | - Marta Perez-Rando
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| | - Juan Nacher
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
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10
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Moiseev KY, Spirichev AA, Vishnyakova PA, Pankrasheva LG, Masliukov PM. Changes of discharge properties of neurons from dorsomedial hypothalamic nuclei during aging in rats. Neurosci Lett 2021; 762:136168. [PMID: 34389479 DOI: 10.1016/j.neulet.2021.136168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/28/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
The hypothalamus is a vital brain center that is participated in the integration of the endocrine and nervous systems and control of the homeostasis and aging. Spontaneous firing activity from single neurons of the dorsomedial hypothalamic nucleus (DMN) was studied extracellularly in vivo in urethane-anaesthetized rats. The discharge patterns of the majority of DMN neurons were irregular, including periods of relatively stable activity interrupted by pauses. Based on the features of interval interspike histogram, we have selected neurons with an irregular arrhythmic activity (50% in young, 46% in adult and 44% in aged rats), with a constant rhythmic activity (18% of neurons in young, 19% in adult and 23% in aged rats), with a wide interspike interval distribution (22% in young, 26% in adult and 25% in aged rats) and cells with bursts of two or three spikes (10% in young, 9% in adult and 8% in aged rats). The firing rate of DMN neurons was 2.5 ± 0.12 Hz in young and 2.4 ± 0.21 Hz in adult rats and significantly decreased to 1.8 ± 0.17 Hz in aged rats.
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11
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Amanzadeh Jajin E, Esmaeili A, Rahgozar S, Noorbakhshnia M. Quercetin-Conjugated Superparamagnetic Iron Oxide Nanoparticles Protect AlCl 3-Induced Neurotoxicity in a Rat Model of Alzheimer's Disease via Antioxidant Genes, APP Gene, and miRNA-101. Front Neurosci 2021; 14:598617. [PMID: 33716639 PMCID: PMC7947204 DOI: 10.3389/fnins.2020.598617] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/30/2020] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease with cognitive impairment. Oxidative stress in neurons is considered as a reason for development of AD. Antioxidant agents such as quercetin slow down AD progression, but the usage of this flavonoid has limitations because of its low bioavailability. We hypothesized that quercetin-conjugated superparamagnetic iron oxide nanoparticles (QT-SPIONs) have a better neuroprotective effect on AD than free quercetin and regulates the antioxidant, apoptotic, and APP gene, and miRNA-101. In this study, male Wistar rats were subjected to AlCl3, AlCl3 + QT, AlCl3 + SPION, and AlCl3 + QT-SPION for 42 consecutive days. Behavioral tests and qPCR were used to evaluate the efficiency of treatments. Results of behavioral tests revealed that the intensity of cognitive impairment was decelerated at both the middle and end of the treatment period. The effect of QT-SPIONs on learning and memory deficits were closely similar to the control group. The increase in expression levels of APP gene and the decrease in mir101 led to the development of AD symptoms in rats treated with AlCl3 while these results were reversed in the AlCl3 + QT-SPIONs group. This group showed similar results with the control group. QT-SPION also decreased the expression levels of antioxidant enzymes along with increases in expression levels of anti-apoptotic genes. Accordingly, the antioxidant effect of QT-SPION inhibited progression of cognitive impairment via sustaining the balance of antioxidant enzymes in the hippocampus of AD model rats.
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Affiliation(s)
- Elnaz Amanzadeh Jajin
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Abolghasem Esmaeili
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Soheila Rahgozar
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Maryam Noorbakhshnia
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
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12
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McQuail JA, Dunn AR, Stern Y, Barnes CA, Kempermann G, Rapp PR, Kaczorowski CC, Foster TC. Cognitive Reserve in Model Systems for Mechanistic Discovery: The Importance of Longitudinal Studies. Front Aging Neurosci 2021; 12:607685. [PMID: 33551788 PMCID: PMC7859530 DOI: 10.3389/fnagi.2020.607685] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/30/2020] [Indexed: 12/14/2022] Open
Abstract
The goal of this review article is to provide a resource for longitudinal studies, using animal models, directed at understanding and modifying the relationship between cognition and brain structure and function throughout life. We propose that forthcoming longitudinal studies will build upon a wealth of knowledge gleaned from prior cross-sectional designs to identify early predictors of variability in cognitive function during aging, and characterize fundamental neurobiological mechanisms that underlie the vulnerability to, and the trajectory of, cognitive decline. Finally, we present examples of biological measures that may differentiate mechanisms of the cognitive reserve at the molecular, cellular, and network level.
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Affiliation(s)
- Joseph A. McQuail
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Amy R. Dunn
- The Jackson Laboratory, Bar Harbor, ME, United States
| | - Yaakov Stern
- Cognitive Neuroscience Division, Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - Carol A. Barnes
- Departments of Psychology and Neuroscience, University of Arizona, Tucson, AZ, United States
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, United States
| | - Gerd Kempermann
- CRTD—Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), Helmholtz Association of German Research Centers (HZ), Dresden, Germany
| | - Peter R. Rapp
- Laboratory of Behavioral Neuroscience, Neurocognitive Aging Section, National Institute on Aging, Baltimore, MD, United States
| | | | - Thomas C. Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Genetics and Genomics Program, University of Florida, Gainesville, FL, United States
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13
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Moskowitz S, Russ DW, Clark LA, Wages NP, Grooms DR, Woods AJ, Suhr J, Simon JE, O'Shea A, Criss CR, Fadda P, Clark BC. Is impaired dopaminergic function associated with mobility capacity in older adults? GeroScience 2020; 43:1383-1404. [PMID: 33236263 DOI: 10.1007/s11357-020-00303-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/18/2020] [Indexed: 01/14/2023] Open
Abstract
The capacity to move is essential for independence and declines with age. Slow movement speed, in particular, is strongly associated with negative health outcomes. Prior research on mobility (herein defined as movement slowness) and aging has largely focused on musculoskeletal mechanisms and processes. More recent work has provided growing evidence for a significant role of the nervous system in contributing to reduced mobility in older adults. In this article, we report four pieces of complementary evidence from behavioral, genetic, and neuroimaging experiments that, we believe, provide theoretical support for the assertion that the basal ganglia and its dopaminergic function are responsible, in part, for age-related reductions in mobility. We report four a posteriori findings from an existing dataset: (1) slower central activation of ballistic force development is associated with worse mobility among older adults; (2) older adults with the Val/Met intermediate catecholamine-O-methyl-transferase (COMT) genotype involved in dopamine degradation exhibit greater mobility than their homozygous counterparts; (3) there are moderate relationships between performance times from a series of lower and upper extremity tasks supporting the notion that movement speed in older adults is a trait-like attribute; and (4) there is a relationship of functional connectivity within the medial orbofrontal (mOFC) cortico-striatal network and measures of mobility, suggesting that a potential neural mechanism for impaired mobility with aging is the deterioration of the integrity of key regions within the mOFC cortico-striatal network. These findings align with recent basic and clinical science work suggesting that the basal ganglia and its dopaminergic function are mechanistically linked to age-related reductions in mobility capacity.
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Affiliation(s)
- Simon Moskowitz
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA
| | - David W Russ
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA.,School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH, USA.,School of Physical Therapy & Rehabilitation Sciences, University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Leatha A Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA.,Department of Biomedical Sciences at Ohio University, Athens, OH, USA.,Department of Family Medicine at Ohio University, Athens, OH, USA
| | - Nathan P Wages
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA.,Department of Biomedical Sciences at Ohio University, Athens, OH, USA
| | - Dustin R Grooms
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA.,School of Applied Health and Wellness, Ohio University, Athens, OH, USA
| | - Adam J Woods
- Center for Cognitive Aging and Memory, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Julie Suhr
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA.,Department of Psychology, Ohio University, Athens, OH, USA
| | - Janet E Simon
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA.,School of Applied Health and Wellness, Ohio University, Athens, OH, USA
| | - Andrew O'Shea
- Center for Cognitive Aging and Memory, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Cody R Criss
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA
| | - Paolo Fadda
- Genomics Shared Resource-Comprehensive Cancer Center, The Ohio State University, Athens, OH, USA
| | - Brian C Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, 250 Irvine Hall, Athens, OH, 45701, USA. .,Department of Biomedical Sciences at Ohio University, Athens, OH, USA. .,Division of Geriatric Medicine at Ohio University, Athens, OH, USA.
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14
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Severin D, Gallagher M, Kirkwood A. Afterhyperpolarization amplitude in CA1 pyramidal cells of aged Long-Evans rats characterized for individual differences. Neurobiol Aging 2020; 96:43-48. [PMID: 32932137 DOI: 10.1016/j.neurobiolaging.2020.07.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/06/2020] [Accepted: 07/25/2020] [Indexed: 11/18/2022]
Abstract
Altered neural excitability is considered a prominent contributing factor to cognitive decline during aging. A clear example is the excess neural activity observed in several temporal lobe structures of cognitively impaired older individuals in rodents and humans. At a cellular level, aging-related changes in mechanisms regulating intrinsic excitability have been well examined in pyramidal cells of the CA1 hippocampal subfield. Studies in the inbred Fisher 344 rat strain document an age-related increase in the slow afterhyperpolarization (AHP) that normally occurs after a burst of action potentials, and serves to reduce subsequent firing. We evaluated the status of the AHP in the outbred Long-Evans rat, a well-established model for studying individual differences in neurocognitive aging. In contrast to the findings reported in the Fisher 344 rats, in the Long-Evan rats we detected a selective reduction in AHP in cognitively impaired aged individuals. We discuss plausible scenarios to account for these differences and also discuss possible implications of these differences.
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Affiliation(s)
- Daniel Severin
- Department of Neurosciences, Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Alfredo Kirkwood
- Department of Neurosciences, Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA.
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15
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Paw-Min-Thein-Oo, Sakimoto Y, Kida H, Mitsushima D. Proximodistal Heterogeneity in Learning-promoted Pathway-specific Plasticity at Dorsal CA1 Synapses. Neuroscience 2020; 437:184-195. [PMID: 32360699 DOI: 10.1016/j.neuroscience.2020.04.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 01/28/2023]
Abstract
Contextual learning requires the delivery of AMPA receptors to CA1 synapses in the dorsal hippocampus. However, proximodistal heterogeneity of pathway-specific plasticity remains unclear. Here, we examined the proximodistal heterogeneity in learning-induced plasticity at the CA1 synapses with inputs from the entorhinal cortex layer III (ECIII) or from CA3. We subjected male rats to an inhibitory avoidance task and prepared acute hippocampal slices for whole-cell patch clamp experiments, where we stimulated ECIII-CA1 or CA3-CA1 input fibers to analyze evoked excitatory postsynaptic currents (EPSCs). Compared to untrained controls, trained rats exhibited higher AMPA/NMDA current ratios at CA3-CA1 synapses of proximal and intermediate, but not distal CA1 neurons, which suggested that region-specific plasticity occurred after learning. Moreover, trained rats exhibited higher AMPA/NMDA current ratios at ECIII-CA1 synapses of intermediate and distal, but not proximal CA1 neurons. These findings suggested the presence of proximodistal heterogeneity in pathway-specific postsynaptic plasticity. Regarding presynaptic plasticity, training slightly, but significantly increased the paired-pulse ratios of CA3-CA1 synapses of proximal and intermediate, but not distal CA1 neurons. Moreover, trained rats exhibited higher paired-pulse ratios at ECIII-CA1 synapses of intermediate and distal, but not proximal CA1 neurons, which suggested region-specific presynaptic plasticity. Finally, learning was clearly prevented by the bilateral microinjection of a plasticity blocker in the proximal or intermediate, but not distal CA1 subfields, which suggested functional heterogeneity along the proximodistal axis. Understanding region- and pathway-specific plasticity at dorsal CA1 synapses could aid in controlling encoded memory.
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Affiliation(s)
- Paw-Min-Thein-Oo
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Hiroyuki Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan.
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16
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Gardner RS, Newman LA, Mohler EG, Tunur T, Gold PE, Korol DL. Aging is not equal across memory systems. Neurobiol Learn Mem 2020; 172:107232. [PMID: 32315762 DOI: 10.1016/j.nlm.2020.107232] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/10/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022]
Abstract
The present experiments compared the effects of aging on learning several hippocampus- and striatum-sensitive tasks in young (3-4 month) and old (24-28 month) male Fischer-344 rats. Across three sets of tasks, aging was accompanied not only by deficits on hippocampal tasks but also by maintained or even enhanced abilities on striatal tasks. On two novel object recognition tasks, rats showed impaired performance on a hippocampal object location task but enhanced performance on a striatal object replacement task. On a dual solution task, young rats predominately used hippocampal solutions and old rats used striatal solutions. In addition, on two maze tasks optimally solved using either hippocampus-sensitive place or striatum-sensitive response strategies, relative to young rats, old rats had impaired learning on the place version but equivalent learning on the response version. Because glucose treatments can reverse deficits in learning and memory across many tasks and contexts, levels of available glucose in the brain may have particular importance in cognitive aging observed across tasks and memory systems. During place learning, training-related rises in extracellular glucose levels were attenuated in the hippocampus of old rats compared to young rats. In contrast, glucose levels in the striatum increased comparably in young and old rats trained on either the place or response task. These extracellular brain glucose responses to training paralleled the impairment in hippocampus-sensitive learning and the sparing of striatum-sensitive learning seen as rats age, suggesting a link between age-related changes in learning and metabolic substrate availability in these brain regions.
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Affiliation(s)
- R S Gardner
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States.
| | - L A Newman
- Department of Psychological Science, Vassar College, Poughkeepsie, NY 12604, United States
| | - E G Mohler
- Research and Development, AbbVie, North Chicago, IL 60064, United States
| | - T Tunur
- Department of Kinesiology, California State University San Marcos, San Marcos, CA 92096, United States
| | - P E Gold
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States
| | - D L Korol
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States.
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