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Cooper CP, Cheng L, Bhatti J, Melendez ER, Huell D, Banuelos C, Perez E, Long JM, Rapp PR. Cerebellum Purkinje cell vulnerability in aged rats with memory impairment. J Comp Neurol 2024; 532:e25610. [PMID: 38605461 PMCID: PMC11027960 DOI: 10.1002/cne.25610] [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: 11/06/2023] [Revised: 01/22/2024] [Accepted: 03/24/2024] [Indexed: 04/13/2024]
Abstract
The cerebellum is involved in higher order cognitive function and is susceptible to age-related atrophy. However, limited evidence has directly examined the cerebellum's role in cognitive aging. To interrogate potential substrates of the relationship between cerebellar structure and memory in aging, here we target the Purkinje cells (PCs). The sole output neurons of the cerebellum, PC loss and/or degeneration underlie a variety of behavioral abnormalities. Using a rat model of normal cognitive aging, we immunostained sections through the cerebellum for the PC-specific protein, calbindin-D28k. Although morphometric quantification revealed no significant difference in total PC number as a function of age or cognitive status, regional cell number was a more robust correlate of memory performance in the young cerebellum than in aged animals. Parallel biochemical analysis of PC-specific protein levels in whole cerebellum additionally revealed that calbindin-D28k and Purkinje cell protein-2 (pcp-2) levels were lower selectively in aged rats with spatial memory impairment compared to both young animals and aged rats with intact memory. These results suggest that cognitive aging is associated with cerebellum vulnerability, potentially reflecting disruption of the cerebellum-medial temporal lobe network.
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Affiliation(s)
- C’iana P. Cooper
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Liam Cheng
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Jafar Bhatti
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Edward R. Melendez
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Derek Huell
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Cristina Banuelos
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Evelyn Perez
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Jeffrey M. Long
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Peter R. Rapp
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
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Bañuelos C, Kittleson JR, LaNasa KH, Galiano CS, Roth SM, Perez EJ, Long JM, Roberts MT, Fong S, Rapp PR. Cognitive Aging and the Primate Basal Forebrain Revisited: Disproportionate GABAergic Vulnerability Revealed. J Neurosci 2023; 43:8425-8441. [PMID: 37798131 PMCID: PMC10711728 DOI: 10.1523/jneurosci.0456-23.2023] [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: 03/13/2023] [Revised: 09/22/2023] [Accepted: 09/23/2023] [Indexed: 10/07/2023] Open
Abstract
Basal forebrain (BF) projections to the hippocampus and cortex are anatomically positioned to influence a broad range of cognitive capacities that are known to decline in normal aging, including executive function and memory. Although a long history of research on neurocognitive aging has focused on the role of the cholinergic basal forebrain system, intermingled GABAergic cells are numerically as prominent and well positioned to regulate the activity of their cortical projection targets, including the hippocampus and prefrontal cortex. The effects of aging on noncholinergic BF neurons in primates, however, are largely unknown. In this study, we conducted quantitative morphometric analyses in brains from young adult (6 females, 2 males) and aged (11 females, 5 males) rhesus monkeys (Macaca mulatta) that displayed significant impairment on standard tests that require the prefrontal cortex and hippocampus. Cholinergic (ChAT+) and GABAergic (GAD67+) neurons were quantified through the full rostrocaudal extent of the BF. Total BF immunopositive neuron number (ChAT+ plus GAD67+) was significantly lower in aged monkeys compared with young, largely because of fewer GAD67+ cells. Additionally, GAD67+ neuron volume was greater selectively in aged monkeys without cognitive impairment compared with young monkeys. These findings indicate that the GABAergic component of the primate BF is disproportionally vulnerable to aging, implying a loss of inhibitory drive to cortical circuitry. Moreover, adaptive reorganization of the GABAergic circuitry may contribute to successful neurocognitive outcomes.SIGNIFICANCE STATEMENT A long history of research has confirmed the role of the basal forebrain in cognitive aging. The majority of that work has focused on BF cholinergic neurons that innervate the cortical mantle. Codistributed BF GABAergic populations are also well positioned to influence cognitive function, yet little is known about this prominent neuronal population in the aged brain. In this unprecedented quantitative comparison of both cholinergic and GABAergic BF neurons in young and aged rhesus macaques, we found that neuron number is significantly reduced in the aged BF compared with young, and that this reduction is disproportionately because of a loss of GABAergic neurons. Together, our findings encourage a new perspective on the functional organization of the primate BF in neurocognitive aging.
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Affiliation(s)
- Cristina Bañuelos
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Joshua R Kittleson
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Katherine H LaNasa
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Christina S Galiano
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Stephanie M Roth
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Evelyn J Perez
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Jeffrey M Long
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
| | - Mary T Roberts
- California National Primate Research Center, University of California, Davis, Davis, California 95616
| | - Sania Fong
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
- California National Primate Research Center, University of California, Davis, Davis, California 95616
| | - Peter R Rapp
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224
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Branch AE, Glover LR, Gallagher M. Individual differences in age-related neurocognitive outcomes: within-subject assessment of memory for odors. Front Aging Neurosci 2023; 15:1238444. [PMID: 37842120 PMCID: PMC10569039 DOI: 10.3389/fnagi.2023.1238444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023] Open
Abstract
Cognitive decline is a common feature of aging, particularly in memory domains supported by the medial temporal lobe (MTL). The ability to identify intervention strategies to treat or prevent this decline is challenging due to substantial variability between adults in terms of age of onset, rate and severity of decline, and many factors that could influence cognitive reserve. These factors can be somewhat mitigated by use of within-subject designs. Aged outbred Long-Evans rats have proven useful for identifying translationally relevant substrates contributing to age-related decline in MTL-dependent memory. In this population, some animals show reliable impairment on MTL-dependent tasks while others perform within the range of young adult rats. However, currently there are relatively few within-subject behavior protocols for assessing MTL function over time, and most require extensive training and appetitive motivation for associative learning. In the current study, we aimed to test whether water maze learning impairments in aged Long-Evans rats would be predictive of delayed recognition memory impairments and whether these odor memory impairments would be stable within subjects over multiple rounds of testing.
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Affiliation(s)
- Audrey E. Branch
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Lucas R. Glover
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, United States
- Johns Hopkins Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States
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Cooper CP, Shafer AT, Armstrong NM, An Y, Erus G, Davatzikos C, Ferrucci L, Rapp PR, Resnick SM. Associations of baseline and longitudinal change in cerebellum volume with age-related changes in verbal learning and memory. Neuroimage 2023; 272:120048. [PMID: 36958620 DOI: 10.1016/j.neuroimage.2023.120048] [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: 10/15/2022] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/25/2023] Open
Abstract
The cerebellum is involved in higher-order cognitive functions, e.g., learning and memory, and is susceptible to age-related atrophy. Yet, the cerebellum's role in age-related cognitive decline remains largely unknown. We investigated cross-sectional and longitudinal associations between cerebellar volume and verbal learning and memory. Linear mixed effects models and partial correlations were used to examine the relationship between changes in cerebellum volumes (total cerebellum, cerebellum white matter [WM], cerebellum hemisphere gray matter [GM], and cerebellum vermis subregions) and changes in verbal learning and memory performance among 549 Baltimore Longitudinal Study of Aging participants (2,292 visits). All models were adjusted by baseline demographic characteristics (age, sex, race, education), and APOE e4 carrier status. In examining associations between change with change, we tested an additional model that included either hippocampal (HC), cuneus, or postcentral gyrus (PoCG) volumes to assess whether cerebellar volumes were uniquely associated with verbal learning and memory. Cross-sectionally, the association of baseline cerebellum GM and WM with baseline verbal learning and memory was age-dependent, with the oldest individuals showing the strongest association between volume and performance. Baseline volume was not significantly associated with change in learning and memory. However, analysis of associations between change in volumes and changes in verbal learning and memory showed that greater declines in verbal memory were associated with greater volume loss in cerebellum white matter, and preserved GM volume in cerebellum vermis lobules VI-VII. The association between decline in verbal memory and decline in cerebellar WM volume remained after adjustment for HC, cuneus, and PoCG volume. Our findings highlight that associations between cerebellum volume and verbal learning and memory are age-dependent and regionally specific.
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Affiliation(s)
- C'iana P Cooper
- Neurocognitive Aging Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Andrea T Shafer
- Brain Aging and Behavior Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Nicole M Armstrong
- Brain Aging and Behavior Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland; Department of Psychiatry and Human Behavior, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Yang An
- Brain Aging and Behavior Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Guray Erus
- Section of Biomedical Image Analysis, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Christos Davatzikos
- Section of Biomedical Image Analysis, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Luigi Ferrucci
- Translational Gerontology Branch, Longitudinal Studies Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Peter R Rapp
- Neurocognitive Aging Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Susan M Resnick
- Brain Aging and Behavior Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland.
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Matsuda K, Nagasaka K, Kato J, Takashima I, Higo N. Structural plasticity of motor cortices assessed by voxel-based morphometry and immunohistochemical analysis following internal capsular infarcts in macaque monkeys. Cereb Cortex Commun 2022; 3:tgac046. [PMID: 36457456 PMCID: PMC9706438 DOI: 10.1093/texcom/tgac046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 12/23/2023] Open
Abstract
Compensatory plastic changes in the remaining intact brain regions are supposedly involved in functional recovery following stroke. Previously, a compensatory increase in cortical activation occurred in the ventral premotor cortex (PMv), which contributed to the recovery of dexterous hand movement in a macaque model of unilateral internal capsular infarcts. Herein, we investigated the structural plastic changes underlying functional changes together with voxel-based morphometry (VBM) analysis of magnetic resonance imaging data and immunohistochemical analysis using SMI-32 antibody in a macaque model. Unilateral internal capsular infarcts were pharmacologically induced in 5 macaques, and another 5 macaques were used as intact controls for immunohistochemical analysis. Three months post infarcts, we observed significant increases in the gray matter volume (GMV) and the dendritic arborization of layer V pyramidal neurons in the contralesional rostral PMv (F5) as well as the primary motor cortex (M1). The histological analysis revealed shrinkage of neuronal soma and dendrites in the ipsilesional M1 and several premotor cortices, despite not always detecting GMV reduction by VBM analysis. In conclusion, compensatory structural changes occur in the contralesional F5 and M1 during motor recovery following internal capsular infarcts, and the dendritic growth of pyramidal neurons is partially correlated with GMV increase.
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Affiliation(s)
- Kohei Matsuda
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 3058568, Japan
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 3058577, Japan
| | - Kazuaki Nagasaka
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 3058568, Japan
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 9503198, Japan
- Department of Physical Therapy, Faculty of Rehabilitation, Niigata University of Health and Welfare, Niigata 9503198, Japan
| | - Junpei Kato
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 3058568, Japan
- Faculty of Medicine, University of Tsukuba, Ibaraki 3058577, Japan
| | - Ichiro Takashima
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 3058568, Japan
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 3058577, Japan
| | - Noriyuki Higo
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 3058568, Japan
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