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Insight into the Effects of High-Altitude Hypoxic Exposure on Learning and Memory. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4163188. [PMID: 36160703 PMCID: PMC9492407 DOI: 10.1155/2022/4163188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 08/22/2022] [Indexed: 02/05/2023]
Abstract
The earth land area is heterogeneous in terms of elevation; about 45% of its land area belongs to higher elevation with altitude above 500 meters compared to sea level. In most cases, oxygen concentration decreases as altitude increases. Thus, high-altitude hypoxic stress is commonly faced by residents in areas with an average elevation exceeding 2500 meters and those who have just entered the plateau. High-altitude hypoxia significantly affects advanced neurobehaviors including learning and memory (L&M). Hippocampus, the integration center of L&M, could be the most crucial target affected by high-altitude hypoxia exposure. Based on these points, this review thoroughly discussed the relationship between high-altitude hypoxia and L&M impairment, in terms of hippocampal neuron apoptosis and dysfunction, neuronal oxidative stress disorder, neurotransmitters and related receptors, and nerve cell energy metabolism disorder, which is of great significance to find potential targets for medical intervention. Studies illustrate that the mechanism of L&M damaged by high-altitude hypoxia should be further investigated based on the entire review of issues related to this topic.
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Heywood A, Stocks J, Schneider JA, Arfanakis K, Bennett DA, Beg MF, Wang L. The unique effect of TDP-43 on hippocampal subfield morphometry and cognition. Neuroimage Clin 2022; 35:103125. [PMID: 36002965 PMCID: PMC9421500 DOI: 10.1016/j.nicl.2022.103125] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 01/18/2023]
Abstract
•We explored postmortem TDP-43 burden and antemortem hippocampal surface deformation. •TDP-43 was uniquely associated with inward deformation in the hippocampus. •Deformation patterns account for co-existing disease showing TDP-43′s unique effect. •Deformation was significantly correlated with cognition scores.
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Affiliation(s)
- Ashley Heywood
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Jane Stocks
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Julie A Schneider
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Konstantinos Arfanakis
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | | | - Lei Wang
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Copper, Iron, Selenium and Lipo-Glycemic Dysmetabolism in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22179461. [PMID: 34502369 PMCID: PMC8431716 DOI: 10.3390/ijms22179461] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/18/2022] Open
Abstract
The aim of the present review is to discuss traditional hypotheses on the etiopathogenesis of Alzheimer's disease (AD), as well as the role of metabolic-syndrome-related mechanisms in AD development with a special focus on advanced glycation end-products (AGEs) and their role in metal-induced neurodegeneration in AD. Persistent hyperglycemia along with oxidative stress results in increased protein glycation and formation of AGEs. The latter were shown to possess a wide spectrum of neurotoxic effects including increased Aβ generation and aggregation. In addition, AGE binding to receptor for AGE (RAGE) induces a variety of pathways contributing to neuroinflammation. The existing data also demonstrate that AGE toxicity seems to mediate the involvement of copper (Cu) and potentially other metals in AD pathogenesis. Specifically, Cu promotes AGE formation, AGE-Aβ cross-linking and up-regulation of RAGE expression. Moreover, Aβ glycation was shown to increase prooxidant effects of Cu through Fenton chemistry. Given the role of AGE and RAGE, as well as metal toxicity in AD pathogenesis, it is proposed that metal chelation and/or incretins may slow down oxidative damage. In addition, selenium (Se) compounds seem to attenuate the intracellular toxicity of the deranged tau and Aβ, as well as inhibiting AGE accumulation and metal-induced neurotoxicity.
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Du C, Chen Y, Chen K, Zhang Z. Disrupted anterior and posterior hippocampal structural networks correlate impaired verbal memory and spatial memory in different subtypes of mild cognitive impairment. Eur J Neurol 2021; 28:3955-3964. [PMID: 34310802 DOI: 10.1111/ene.15036] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 07/21/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE The anterior and posterior hippocampal networks represent verbal and spatial memory, respectively, and may play different roles in the pathological mechanism of amnestic mild cognitive impairment (aMCI) and non-amnestic MCI (naMCI), which has not been explored. METHODS A total of 990 older adults with 791 normal controls (NCs) (65 ± 6 years, 502 women), 140 aMCI (66 ± 7 years, 84 women) and 59 naMCI (66 ± 7 years, 38 women) were included. A multivariate method, partial least squares, was used to assess the structural covariance networks of the anterior hippocampus (aHC) and posterior hippocampus (pHC), and their relationships with verbal memory and spatial memory in the three groups. RESULTS Three aHC and pHC structural covariance network patterns emerged: (1) the age pattern; (2) the specific aMCI pattern; and (3) the spatial memory pattern. Furthermore, aMCI patients had more extensive and severe damage in the three patterns, and correlated with greater decline in verbal memory, which was mainly characterized by the aHC network. CONCLUSIONS The aMCI and naMCI showed different patterns and damage in the structural covariance networks, and functional segregation of the aHC and pHC networks still exists in the process of pathological aging. A potential neural explanation is provided for the conversion of aMCI and naMCI into different types of dementia in the future.
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Affiliation(s)
- Chao Du
- State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.,Beijing Aging Brain Rejuvenation Initiative Centre, Beijing Normal University, Beijing, China
| | - Yaojing Chen
- State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.,Beijing Aging Brain Rejuvenation Initiative Centre, Beijing Normal University, Beijing, China
| | - Kewei Chen
- Banner Alzheimer's Institute, Phoenix, AZ, USA.,Shanghai Green Valley Pharmaceutical Company, Ltd., Shanghai, China
| | - Zhanjun Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.,Beijing Aging Brain Rejuvenation Initiative Centre, Beijing Normal University, Beijing, China
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Saeedi M, Rastegari A, Hariri R, Mirfazli SS, Mahdavi M, Edraki N, Firuzi O, Akbarzadeh T. Design and Synthesis of Novel Arylisoxazole-Chromenone Carboxamides: Investigation of Biological Activities Associated with Alzheimer's Disease. Chem Biodivers 2020; 17:e1900746. [PMID: 32154628 DOI: 10.1002/cbdv.201900746] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/09/2020] [Indexed: 12/17/2022]
Abstract
A novel series of hybrid arylisoxazole-chromenone carboxamides were designed, synthesized, and evaluated for their cholinesterase (ChE) inhibitory activity based on the modified Ellman's method. Among synthesized compounds, 5-(3-nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide depicted the most acetylcholinesterase (AChE) inhibitory activity (IC50 =1.23 μm) and 5-(3-chlorophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide was found to be the most potent butyrylcholinesterase (BChE) inhibitor (IC50 =9.71 μm). 5-(3-Nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide was further investigated for its BACE1 inhibitory activity as well as neuroprotectivity and metal chelating ability as important factors involved in onset and progress of Alzheimer's disease. It could inhibit BACE1 by 48.46 % at 50 μm. It also showed 6.4 % protection at 25 μm and satisfactory chelating ability toward Zn2+ , Fe2+ , and Cu2+ ions. Docking studies of 5-(3-nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide and 5-(3-chlorophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide confirmed desired interactions with those amino acid residues of the AChE and BChE, respectively.
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Affiliation(s)
- Mina Saeedi
- Medicinal Plants Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, 14155, Tehran, Iran.,Persian Medicine and Pharmacy Research Center, Tehran University of Medical Sciences, 14155, Tehran, Iran
| | - Arezoo Rastegari
- Persian Medicine and Pharmacy Research Center, Tehran University of Medical Sciences, 14155, Tehran, Iran.,Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, 14155, Tehran, Iran
| | - Roshanak Hariri
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, 14155, Tehran, Iran
| | - Seyedeh Sara Mirfazli
- Department of Medicinal Chemistry, School of Pharmacy-International Campus, Iran University of Medical Sciences, 14665, Tehran, Iran
| | - Mohammad Mahdavi
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, 14155, Tehran, Iran
| | - Najmeh Edraki
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, 71348, Shiraz, Iran
| | - Omidreza Firuzi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, 71348, Shiraz, Iran
| | - Tahmineh Akbarzadeh
- Persian Medicine and Pharmacy Research Center, Tehran University of Medical Sciences, 14155, Tehran, Iran.,Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, 14155, Tehran, Iran
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Ofori E, DeKosky ST, Febo M, Colon-Perez L, Chakrabarty P, Duara R, Adjouadi M, Golde TE, Vaillancourt DE. Free-water imaging of the hippocampus is a sensitive marker of Alzheimer's disease. NEUROIMAGE-CLINICAL 2019; 24:101985. [PMID: 31470214 PMCID: PMC6722298 DOI: 10.1016/j.nicl.2019.101985] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/30/2019] [Accepted: 08/14/2019] [Indexed: 11/25/2022]
Abstract
Validating sensitive markers of hippocampal degeneration is fundamental for understanding neurodegenerative conditions such as Alzheimer's disease. In this paper, we test the hypothesis that free-water in the hippocampus will be more sensitive to early stages of cognitive decline than hippocampal volume, and that free-water in hippocampus will increase across distinct clinical stages of Alzheimer's disease. We examined two separate cohorts (N = 126; N = 112) of cognitively normal controls, early and late mild cognitive impairment (MCI), and Alzheimer's disease. Demographic, clinical, diffusion-weighted and T1-weighted imaging, and positron emission tomography (PET) imaging were assessed. Results indicated elevated hippocampal free-water in early MCI individuals compared to controls across both cohorts. In contrast, there was no difference in volume of these regions between controls and early MCI. ADNI free-water values in the hippocampus was associated with low CSF AB1–42 levels and high global amyloid PET values. Free-water imaging of the hippocampus can serve as an early stage marker for AD and provides a complementary measure of AD neurodegeneration using non-invasive imaging. Free-water imaging is a useful technique for detecting neurodegeneration Increased free-water in the left hippocampus for early MCI compared with cognitive normal controls across multiple sites We propose that changes in free-water may indicate hippocampal degeneration in AD
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Affiliation(s)
- Edward Ofori
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville FL 32611, United States of America; College of Health Solutions, Arizona State University, Phoenix, AZ, United States of America.
| | - Steven T DeKosky
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville FL 32611, United States of America
| | - Marcelo Febo
- Department of Psychiatry, University of Florida, Gainesville FL 32611, United States of America; Department of Neuroscience, University of Florida, Gainesville FL 32611, United States of America
| | - Luis Colon-Perez
- Department of Psychiatry, University of Florida, Gainesville FL 32611, United States of America
| | - Paramita Chakrabarty
- Department of Neuroscience, University of Florida, Gainesville FL 32611, United States of America; Center for Translational Research in Neurodegenerative Diseases, University of Florida, Gainesville FL 32611, United States of America
| | - Ranjan Duara
- Wein Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL 33140, United States of America
| | - Malek Adjouadi
- Center for Advanced Technology and Education, Florida International University, Miami, FL 33174, United States of America
| | - Todd E Golde
- Department of Neuroscience, University of Florida, Gainesville FL 32611, United States of America; Center for Translational Research in Neurodegenerative Diseases, University of Florida, Gainesville FL 32611, United States of America
| | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville FL 32611, United States of America; Department of Neurology, University of Florida, Gainesville FL-32611, United States of America; Department of Biomedical Engineering, University of Florida, Gainesville FL-32611, United States of America
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Gicas KM, Thornton AE, Waclawik K, Wang N, Jones AA, Panenka WJ, Lang DJ, Smith GN, Vila-Rodriguez F, Leonova O, Barr AM, Procyshyn RM, Buchanan T, Su W, Vertinsky AT, Rauscher A, MacEwan GW, Honer WG. Volumes of the Hippocampal Formation Differentiate Component Processes of Memory in a Community Sample of Homeless and Marginally Housed Persons. Arch Clin Neuropsychol 2019; 34:548-562. [PMID: 30407496 DOI: 10.1093/arclin/acy066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE Persons who are homeless or marginally housed exhibit significant cognitive dysfunction, with memory being the most impaired domain. Hippocampal subfield volumes have been found to differentially relate to component processes of memory. The neural correlates of memory have not been previously examined in marginalized persons who are understudied and underserved. We examined whether hippocampal subfields and entorhinal cortex volumes are uniquely related to indices of verbal episodic memory using the Hopkins Verbal Learning Test - Revised. METHOD Data was used from a large sample of community dwelling homeless and marginally housed adults (N = 227). Regression analyses were conducted to examine hippocampal subfield volumes (CA1, CA3, CA4, dentate gyrus, subiculum) and entorhinal cortex, and their associations with measures of verbal immediate recall, learning slope, and verbal delayed recall. RESULTS Greater CA3 subfield volume was associated with better performance on an index of encoding (immediate recall), but only in older individuals. Greater CA1 and subiculum volumes were associated with better performance on immediate and delayed recall (measures that tap into retrieval processes), but not with learning slope (a more pure index of encoding). Entorhinal cortex volume was related to all components of memory beyond total hippocampal volume. CONCLUSIONS Our results suggest common neuroanatomical correlates of memory dysfunction in large sample of marginalized persons, and these are uniquely related to different components of memory. These findings have clinical relevance for marginalized populations and theoretical relevance to the growing literature on functional specialization of the hippocampal subfields.
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Affiliation(s)
- Kristina M Gicas
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Allen E Thornton
- Department of Psychology, Simon Fraser University, Burnaby, Canada
| | | | - Nena Wang
- Department of Psychology, Simon Fraser University, Burnaby, Canada
| | - Andrea A Jones
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - William J Panenka
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Donna J Lang
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Geoff N Smith
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | | | - Olga Leonova
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Alasdair M Barr
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Ric M Procyshyn
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Tari Buchanan
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Wayne Su
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | | | - Alexander Rauscher
- Department of Paediatrics, University of British Columbia, Vancouver, Canada
| | - G William MacEwan
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - William G Honer
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
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Sarica A, Vasta R, Novellino F, Vaccaro MG, Cerasa A, Quattrone A. MRI Asymmetry Index of Hippocampal Subfields Increases Through the Continuum From the Mild Cognitive Impairment to the Alzheimer's Disease. Front Neurosci 2018; 12:576. [PMID: 30186103 PMCID: PMC6111896 DOI: 10.3389/fnins.2018.00576] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/30/2018] [Indexed: 12/14/2022] Open
Abstract
Objective: It is well-known that the hippocampus presents significant asymmetry in Alzheimer's disease (AD) and that difference in volumes between left and right exists and varies with disease progression. However, few works investigated whether the asymmetry degree of subfields of hippocampus changes through the continuum from Mild Cognitive Impairment (MCI) to AD. Thus, aim of the present work was to evaluate the Asymmetry Index (AI) of hippocampal substructures as possible MRI biomarkers of Dementia. Moreover, we aimed to assess whether the subfields presented peculiar differences between left and right hemispheres. We also investigated the relationship between the asymmetry magnitude in hippocampal subfields and the decline of verbal memory as assessed by Rey's auditory verbal learning test (RAVLT). Methods: Four-hundred subjects were selected from ADNI, equally divided into healthy controls (HC), AD, stable MCI (sMCI), and progressive MCI (pMCI). The structural baseline T1s were processed with FreeSurfer 6.0 and volumes of whole hippocampus (WH) and 12 subfields were extracted. The AI was calculated as: (|Left-Right|/(Left+Right))*100. ANCOVA was used for evaluating AI differences between diagnoses, while paired t-test was applied for assessing changes between left and right volumes, separately for each group. Partial correlation was performed for exploring relationship between RAVLT summary scores (Immediate, Learning, Forgetting, Percent Forgetting) and hippocampal substructures AI. The statistical threshold was Bonferroni corrected p < 0.05/13 = 0.0038. Results: We found a general trend of increased degree of asymmetry with increasing severity of diagnosis. Indeed, AD presented the higher magnitude of asymmetry compared with HC, sMCI and pMCI, in the WH (AI mean 5.13 ± 4.29 SD) and in each of its twelve subfields. Moreover, we found in AD a significant negative correlation (r = -0.33, p = 0.00065) between the AI of parasubiculum (mean 12.70 ± 9.59 SD) and the RAVLT Learning score (mean 1.70 ± 1.62 SD). Conclusions: Our findings showed that hippocampal subfields AI varies differently among the four groups HC, sMCI, pMCI, and AD. Moreover, we found-for the first time-that hippocampal substructures had different sub-patterns of lateralization compared with the whole hippocampus. Importantly, the severity in learning rate was correlated with pathological high degree of asymmetry in parasubiculum of AD patients.
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Affiliation(s)
- Alessia Sarica
- Neuroscience Centre, Magna Graecia University, Catanzaro, Italy
| | - Roberta Vasta
- Neuroscience Centre, Magna Graecia University, Catanzaro, Italy
| | - Fabiana Novellino
- Neuroimaging Research Unit, Institute of Molecular Bioimaging and Physiology, National Research Council, Catanzaro, Italy
| | | | - Antonio Cerasa
- Neuroimaging Research Unit, Institute of Molecular Bioimaging and Physiology, National Research Council, Catanzaro, Italy
- S. Anna Institute and Research in Advanced Neurorehabilitation, Crotone, Italy
| | - Aldo Quattrone
- Neuroscience Centre, Magna Graecia University, Catanzaro, Italy
- Neuroimaging Research Unit, Institute of Molecular Bioimaging and Physiology, National Research Council, Catanzaro, Italy
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Zammit AR, Ezzati A, Zimmerman ME, Lipton RB, Lipton ML, Katz MJ. Roles of hippocampal subfields in verbal and visual episodic memory. Behav Brain Res 2017; 317:157-162. [PMID: 27646772 PMCID: PMC6343125 DOI: 10.1016/j.bbr.2016.09.038] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/13/2016] [Accepted: 09/15/2016] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Selective hippocampal (HC) subfield atrophy has been reported in older adults with mild cognitive impairment and Alzheimer's disease. The goal of this study was to investigate the associations between the volume of hippocampal subfields and visual and verbal episodic memory in cognitively normal older adults. METHODS This study was conducted on a subset of 133 participants from the Einstein Aging Study (EAS), a community-based study of non-demented older adults systematically recruited from the Bronx, N.Y. All participants completed comprehensive EAS neuropsychological assessment. Visual episodic memory was assessed using the Complex Figure Delayed Recall subtest from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Verbal episodic memory was assessed using Delayed Recall from the Free and Cued Selective Reminding Test (FCSRT). All participants underwent 3T MRI brain scanning with subsequent automatic measurement of the hemispheric hippocampal subfield volumes (CA1, CA2-CA3, CA4-dente gyrus, presubiculum, and subiculum). We used linear regressions to model the association between hippocampal subfield volumes and visual and verbal episodic memory tests while adjusting for age, sex, education, and total intracranial volume. RESULTS Participants had a mean age of 78.9 (SD=5.1) and 60.2% were female. Total hippocampal volume was associated with Complex Figure Delayed Recall (β=0.31, p=0.001) and FCSRT Delayed Recall (β=0.27, p=0.007); subiculum volume was associated with Complex Figure Delayed Recall (β=0.27, p=0.002) and FCSRT Delayed Recall (β=0.24, p=0.010); CA1 was associated with Complex Figure Delayed Recall (β=0.26, p<0.002) and FCSRT Delayed Recall (β=0.20, p=0.025). CONCLUSIONS Our findings confirm previous research on the specific roles of CA1 and subiculum in episodic memory. Our results suggest that hippocampal subfields have sensitive roles in the process of visual and verbal episodic memory.
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Affiliation(s)
- Andrea R Zammit
- Saul B. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Ali Ezzati
- Saul B. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Neurology, Montefiore Medical Center, Bronx, NY 10467, USA
| | - Molly E Zimmerman
- Saul B. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Psychology, Fordham University, Bronx, NY 10458, USA
| | - Richard B Lipton
- Saul B. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Neurology, Montefiore Medical Center, Bronx, NY 10467, USA; Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Michael L Lipton
- The Gruss Magnetic Resonance Research Center and Departments of Radiology, Psychiatry and Behavioral Sciences and the Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Radiology, Montefiore Medical Center, Bronx, NY 10467, USA
| | - Mindy J Katz
- Saul B. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Hahn C, Lee CU, Won WY, Joo SH, Lim HK. Thalamic Shape and Cognitive Performance in Amnestic Mild Cognitive Impairment. Psychiatry Investig 2016; 13:504-510. [PMID: 27757128 PMCID: PMC5067344 DOI: 10.4306/pi.2016.13.5.504] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/20/2015] [Accepted: 12/08/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This study aimed to investigate thalamic shape alterations and their relationships with various episodic memory impairments in subjects with amnestic mild cognitive impairment (aMCI). METHODS We compared volumes and morphological alterations of the thalamus between aMCI subjects and healthy controls. In addition, we investigated the correlation between thalamic deformations and various memory impairments in aMCI subjects using a comprehensive neuropsychological battery. RESULTS The normalized left thalamic volumes of the aMCI group were significantly smaller than those of the healthy control group (p<0.0001). aMCI subjects exhibited significant thalamic deformations in the left thalamic dorso-medial and antero-medial areas compared with healthy individuals. CERAD-K Word List Memory scores were significantly correlated with the left dorso-medial areas in aMCI subjects. There were no significant correlations between verbal fluency, Boston naming test, constructional praxis, Word List Recognition, and Visuospatial Recall scores and thalamic shape in aMCI subjects. Verbal delayed recall scores were also significantly correlated with the left dorso-medial areas in the aMCI group. CONCLUSION Structural alterations in the thalamic deformations in the left dorso-medial and antero-medial areas might be core underlying neurobiological mechanisms of thalamic dysfunction related to Word List Memory and delayed verbal recall in individuals with aMCI.
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Affiliation(s)
- Changtae Hahn
- Department of Psychiatry, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
| | - Chang-Uk Lee
- Department of Psychiatry, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
| | - Wang Yeon Won
- Department of Psychiatry, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
| | - Soo-Hyun Joo
- Department of Psychiatry, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
| | - Hyun Kook Lim
- Department of Psychiatry, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
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Aaseth J, Alexander J, Bjørklund G, Hestad K, Dusek P, Roos PM, Alehagen U. Treatment strategies in Alzheimer's disease: a review with focus on selenium supplementation. Biometals 2016; 29:827-39. [PMID: 27530256 PMCID: PMC5034004 DOI: 10.1007/s10534-016-9959-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 07/25/2016] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder presenting one of the biggest healthcare challenges in developed countries. No effective treatment exists. In recent years the main focus of AD research has been on the amyloid hypothesis, which postulates that extracellular precipitates of beta amyloid (Aβ) derived from amyloid precursor protein (APP) are responsible for the cognitive impairment seen in AD. Treatment strategies have been to reduce Aβ production through inhibition of enzymes responsible for its formation, or to promote resolution of existing cerebral Aβ plaques. However, these approaches have failed to demonstrate significant cognitive improvements. Intracellular rather than extracellular events may be fundamental in AD pathogenesis. Selenate is a potent inhibitor of tau hyperphosphorylation, a critical step in the formation of neurofibrillary tangles. Some selenium (Se) compounds e.g. selenoprotein P also appear to protect APP against excessive copper and iron deposition. Selenoproteins show anti-inflammatory properties, and protect microtubules in the neuronal cytoskeleton. Optimal function of these selenoenzymes requires higher Se intake than what is common in Europe and also higher intake than traditionally recommended. Supplementary treatment with N-acetylcysteine increases levels of the antioxidative cofactor glutathione and can mediate adjuvant protection. The present review discusses the role of Se in AD treatment and suggests strategies for AD prevention by optimizing selenium intake, in accordance with the metal dysregulation hypothesis. This includes in particular secondary prevention by selenium supplementation to elderly with mild cognitive impairment.
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Affiliation(s)
- Jan Aaseth
- Department of Research, Innlandet Hospital Trust, Brumunddal, Norway.,Department of Public Health, Hedmark University of Applied Sciences, Elverum, Norway
| | - Jan Alexander
- Norwegian Institute of Public Health, Oslo, Norway.,Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Knut Hestad
- Department of Research, Innlandet Hospital Trust, Brumunddal, Norway.,Department of Public Health, Hedmark University of Applied Sciences, Elverum, Norway
| | - Petr Dusek
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Per M Roos
- Institute of Environmental Medicine, IMM, Karolinska Institutet, Nobels väg 13, Box 210, 17177, Stockholm, Sweden. .,Department of Clinical Physiology, St.Goran Hospital, Stockholm, Sweden.
| | - Urban Alehagen
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
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12
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Bengtsson SKS, Johansson M, Bäckström T. Long-term continuous allopregnanolone elevation causes memory decline and hippocampus shrinkage, in female wild-type B6 mice. Horm Behav 2016; 78:160-7. [PMID: 26497250 DOI: 10.1016/j.yhbeh.2015.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 10/02/2015] [Accepted: 10/20/2015] [Indexed: 11/20/2022]
Abstract
Chronic stress in various forms increases the risk for cognitive dysfunction, dementia and Alzheimer's disease. While the pathogenesis behind these findings is unknown, growing evidence suggests that chronic increase in neurosteroid levels, such as allopregnanolone, is part of the mechanism. We treated wild-type C57BL/6J mice with allopregnanolone for 5months, using osmotic pumps. This treatment led to moderately increased levels of allopregnanolone, equivalent to that of mild chronic stress. After an interval of no treatment for 1month, female mice showed impaired learning and memory function in the Morris water maze (MWM) in combination with diminished hippocampus weight and increased cerebellum weight, both correlating to MWM performance. Male mice showed a minor reduction in memory function and no differences in brain structure. We conclude that chronic allopregnanolone elevation can lead to cognitive dysfunction and negative brain alterations. We suggest that allopregnanolone could play a key role in the pathogenesis of stress-induced cognitive disturbances and perhaps dementia.
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Affiliation(s)
- Sara K S Bengtsson
- Umeå Neurosteroid Research Center, Umeå University, Department of Clinical Sciences, Umeå, Sweden.
| | - Maja Johansson
- Umeå Neurosteroid Research Center, Umeå University, Department of Clinical Sciences, Umeå, Sweden; Umecrine Cognition AB, Umeå, Sweden
| | - Torbjörn Bäckström
- Umeå Neurosteroid Research Center, Umeå University, Department of Clinical Sciences, Umeå, Sweden
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13
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Pintzka CW, Håberg AK. Perimenopausal hormone therapy is associated with regional sparing of the CA1 subfield: a HUNT MRI study. Neurobiol Aging 2015; 36:2555-62. [DOI: 10.1016/j.neurobiolaging.2015.05.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/05/2015] [Accepted: 05/31/2015] [Indexed: 01/02/2023]
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14
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Menendez M, Arias-Carrión O. Indices of Regional Brain Atrophy: Formulae and Nomenclature. Cureus 2015; 7:e295. [PMID: 26261753 PMCID: PMC4529332 DOI: 10.7759/cureus.295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 08/03/2015] [Indexed: 11/05/2022] Open
Abstract
The pattern of brain atrophy helps to discriminate normal age-related changes from neurodegenerative diseases. Albeit indices of regional brain atrophy have proven to be a parameter useful in the early diagnosis and differential diagnosis of some neurodegenerative diseases, indices of absolute regional atrophy still have some important limitations. We propose using indices of relative atrophy for representing how the volume of a given region of interest (ROI) changes over time in comparison to changes in global brain measures over the same time. A second problem in morphometric studies is terminology. There is a lack of systematization naming indices and the same measure can be named with different terms by different research groups or imaging softwares. This limits the understanding and discussion of studies. In this technological report, we provide a general description on how to compute indices of absolute and relative regional brain atrophy and propose a standardized nomenclature.
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Affiliation(s)
| | - Oscar Arias-Carrión
- Unidad de Trastornos del Movimiento y Sueño, Hospital General Dr. Manuel Gea Gonzalez
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15
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Peng GP, Feng Z, He FP, Chen ZQ, Liu XY, Liu P, Luo BY. Correlation of hippocampal volume and cognitive performances in patients with either mild cognitive impairment or Alzheimer's disease. CNS Neurosci Ther 2014; 21:15-22. [PMID: 25146658 DOI: 10.1111/cns.12317] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE To evaluate hippocampal volume changes and neuropsychological performances in patients with either amnestic mild cognitive impairment (aMCI) or Alzheimer's disease (AD). METHODS Thirty-eight AD dementia, 22 aMCI patients, and 20 healthy controls were enrolled. Bilateral hippocampal volume was measured concurrently with mini-mental state examination (MMSE), auditory verbal learning test (AVLT), Boston naming test (BNT), and activities of daily living (ADL) test. Baseline and two additional follow-up examinations were conducted. RESULTS Baseline hippocampal volumes were significantly smaller in AD group than that in aMCI and control groups. MMSE, AVLT, ADL, and BNT scores for the AD group were significantly different from that of both aMCI and control groups. Baseline hippocampal volumes were positively correlated with MMSE and AVLT scores in AD and aMCI patients. At follow-up, left hippocampal volume loss was positively correlated with decreased MMSE and AVLT scores both in AD and aMCI groups, while right hippocampal volume loss was positively associated with decreased AVLT performance only in AD group. Increased ADL and decreased BNT scores were positively associated with left hippocampal volume reduction only in the AD group. CONCLUSIONS Current findings provide evidence of a close relationship between hippocampal volume and cognitive performances in patients with AD and aMCI, both at baseline and over follow-up.
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Affiliation(s)
- Guo-Ping Peng
- Department of Neurology, First Affiliated Hospital, Zhejiang University, Hangzhou, China; Laboratory of Brain Medical Center, First Affiliated Hospital, Zhejiang University, Hangzhou, China
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16
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Menéndez-González M, López-Muñiz A, Vega JA, Salas-Pacheco JM, Arias-Carrión O. MTA index: a simple 2D-method for assessing atrophy of the medial temporal lobe using clinically available neuroimaging. Front Aging Neurosci 2014; 6:23. [PMID: 24715861 PMCID: PMC3970022 DOI: 10.3389/fnagi.2014.00023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 02/11/2014] [Indexed: 01/11/2023] Open
Abstract
Background and purpose: Despite a strong correlation to severity of AD pathology, the measurement of medial temporal lobe atrophy (MTA) is not being widely used in daily clinical practice as a criterion in the diagnosis of prodromal and probable AD. This is mainly because the methods available to date are sophisticated and difficult to implement for routine use in most hospitals—volumetric methods—or lack objectivity—visual rating scales. In this pilot study we aim to describe a new, simple and objective method for measuring the rate of MTA in relation to the global atrophy using clinically available neuroimaging and describe the rationale behind this method. Description: This method consists of calculating a ratio with the area of 3 regions traced manually on one single coronal MRI slide at the level of the interpeduncular fossa: (1) the medial temporal lobe (MTL) region (A); (2) the parenchima within the medial temporal region, that includes the hippocampus and the parahippocampal gyrus—the fimbria taenia and plexus choroideus are excluded—(B); and (3) the body of the ipsilateral lateral ventricle (C). Therefrom we can compute the ratio “Medial Temporal Atrophy index” at both sides as follows: MTAi = (A − B)× 10/C. Conclusions: The MTAi is a simple 2D-method for measuring the relative extent of atrophy in the MTL in relation to the global brain atrophy. This method can be useful for a more accurate diagnosis of AD in routine clinical practice. Further studies are needed to assess the usefulness of MTAi in the diagnosis of early AD, in tracking the progression of AD and in the differential diagnosis of AD with other dementias.
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Affiliation(s)
- Manuel Menéndez-González
- Unidad de Neurología, Hospital Álvarez-Buylla Mieres, Spain ; Departamento de Morfología y Biología Celular, Universidad de Oviedo Oviedo, Spain ; Instituto de Neurociencias, Universidad de Oviedo Oviedo, Spain
| | - Alfonso López-Muñiz
- Departamento de Morfología y Biología Celular, Universidad de Oviedo Oviedo, Spain ; Instituto de Neurociencias, Universidad de Oviedo Oviedo, Spain
| | - José A Vega
- Departamento de Morfología y Biología Celular, Universidad de Oviedo Oviedo, Spain
| | - José M Salas-Pacheco
- Instituto de Investigación Científica, Universidad Juárez del Estado de Durango Durango, México
| | - Oscar Arias-Carrión
- Unidad de Trastornos del Movimiento y Sueño (TMS), Hospital General Dr. Manuel Gea González/UNAM México DF, Mexico ; Unidad de Trastornos del Movimiento y Sueño (TMS), Hospital General Ajusco Medio México DF, Mexico
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17
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Dunn CJ, Duffy SL, Hickie IB, Lagopoulos J, Lewis SJG, Naismith SL, Shine JM. Deficits in episodic memory retrieval reveal impaired default mode network connectivity in amnestic mild cognitive impairment. NEUROIMAGE-CLINICAL 2014; 4:473-80. [PMID: 24634833 PMCID: PMC3952352 DOI: 10.1016/j.nicl.2014.02.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 02/13/2014] [Accepted: 02/20/2014] [Indexed: 01/04/2023]
Abstract
Amnestic mild cognitive impairment (aMCI) is believed to represent a transitional stage between normal healthy ageing and the development of dementia. In particular, aMCI patients have been shown to have higher annual transition rates to Alzheimer's Disease (AD) than individuals without cognitive impairment. Despite intensifying interest investigating the neuroanatomical basis of this transition, there remain a number of questions regarding the pathophysiological process underlying aMCI itself. A number of recent studies in aMCI have shown specific impairments in connectivity within the default mode network (DMN), which is a group of regions strongly related to episodic memory capacities. However to date, no study has investigated the integrity of the DMN between patients with aMCI and those with a non-amnestic pattern of MCI (naMCI), who have cognitive impairment, but intact memory storage systems. In this study, we contrasted the DMN connectivity in 24 aMCI and 33 naMCI patients using seed-based resting state fMRI. The two groups showed no statistical difference in their DMN intra-connectivity. However when connectivity was analysed according to performance on measures of episodic memory retrieval, the two groups were separable, with aMCI patients demonstrating impaired functional connectivity between the hippocampal formation and the posterior cingulate cortex. We provide evidence that this lack of connectivity is driven by impaired communication from the posterior cingulate hub and does not simply represent hippocampal atrophy, suggesting that posterior cingulate degeneration is the driving force behind impaired DMN connectivity in aMCI. First trial to explore Default Mode Network (DMN) connectivity between MCI and naMCI Amnestic and nonamnestic MCI groups show similar overall DMN intra-connectivity. aMCI patients have connectivity deficits related to impaired memory retention. Impaired DMN connectivity is driven by deficits in posterior cingulate cortex. Alzheimer’s disease pathology likely evolves from PCC to hippocampus
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Affiliation(s)
- Cameron J Dunn
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
| | - Shantel L Duffy
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
| | - Ian B Hickie
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
| | - Jim Lagopoulos
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
| | - Simon J G Lewis
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
| | - Sharon L Naismith
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
| | - James M Shine
- Healthy Brain Ageing Program, Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, NSW, Australia
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18
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Nestor SM, Gibson E, Gao FQ, Kiss A, Black SE. A direct morphometric comparison of five labeling protocols for multi-atlas driven automatic segmentation of the hippocampus in Alzheimer's disease. Neuroimage 2012; 66:50-70. [PMID: 23142652 DOI: 10.1016/j.neuroimage.2012.10.081] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 10/06/2012] [Accepted: 10/30/2012] [Indexed: 01/18/2023] Open
Abstract
Hippocampal volumetry derived from structural MRI is increasingly used to delineate regions of interest for functional measurements, assess efficacy in therapeutic trials of Alzheimer's disease (AD) and has been endorsed by the new AD diagnostic guidelines as a radiological marker of disease progression. Unfortunately, morphological heterogeneity in AD can prevent accurate demarcation of the hippocampus. Recent developments in automated volumetry commonly use multi-template fusion driven by expert manual labels, enabling highly accurate and reproducible segmentation in disease and healthy subjects. However, there are several protocols to define the hippocampus anatomically in vivo, and the method used to generate atlases may impact automatic accuracy and sensitivity - particularly in pathologically heterogeneous samples. Here we report a fully automated segmentation technique that provides a robust platform to directly evaluate both technical and biomarker performance in AD among anatomically unique labeling protocols. For the first time we test head-to-head the performance of five common hippocampal labeling protocols for multi-atlas based segmentation, using both the Sunnybrook Longitudinal Dementia Study and the entire Alzheimer's Disease Neuroimaging Initiative 1 (ADNI-1) baseline and 24-month dataset. We based these atlas libraries on the protocols of (Haller et al., 1997; Killiany et al., 1993; Malykhin et al., 2007; Pantel et al., 2000; Pruessner et al., 2000), and a single operator performed all manual tracings to generate de facto "ground truth" labels. All methods distinguished between normal elders, mild cognitive impairment (MCI), and AD in the expected directions, and showed comparable correlations with measures of episodic memory performance. Only more inclusive protocols distinguished between stable MCI and MCI-to-AD converters, and had slightly better associations with episodic memory. Moreover, we demonstrate that protocols including more posterior anatomy and dorsal white matter compartments furnish the best voxel-overlap accuracies (Dice Similarity Coefficient=0.87-0.89), compared to expert manual tracings, and achieve the smallest sample sizes required to power clinical trials in MCI and AD. The greatest distribution of errors was localized to the caudal hippocampus and the alveus-fimbria compartment when these regions were excluded. The definition of the medial body did not significantly alter accuracy among more comprehensive protocols. Voxel-overlap accuracies between automatic and manual labels were lower for the more pathologically heterogeneous Sunnybrook study in comparison to the ADNI-1 sample. Finally, accuracy among protocols appears to significantly differ the most in AD subjects compared to MCI and normal elders. Together, these results suggest that selection of a candidate protocol for fully automatic multi-template based segmentation in AD can influence both segmentation accuracy when compared to expert manual labels and performance as a biomarker in MCI and AD.
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Affiliation(s)
- Sean M Nestor
- LC Campbell Cognitive Neurology Research Unit, University of Toronto, Canada; Heart and Stroke Foundation Centre for Stroke Recovery, University of Toronto, Canada; Brain Sciences Research Program, Sunnybrook Research Institute, University of Toronto, Canada; University of Toronto, Institute of Medical Sciences, University of Toronto, University of Toronto, Canada; MD/PhD Program, Faculty of Medicine, University of Toronto, University of Toronto, Canada.
| | - Erin Gibson
- LC Campbell Cognitive Neurology Research Unit, University of Toronto, Canada; Heart and Stroke Foundation Centre for Stroke Recovery, University of Toronto, Canada; Brain Sciences Research Program, Sunnybrook Research Institute, University of Toronto, Canada; University of Toronto, Institute of Medical Sciences, University of Toronto, University of Toronto, Canada
| | - Fu-Qiang Gao
- LC Campbell Cognitive Neurology Research Unit, University of Toronto, Canada; Heart and Stroke Foundation Centre for Stroke Recovery, University of Toronto, Canada; Brain Sciences Research Program, Sunnybrook Research Institute, University of Toronto, Canada
| | - Alex Kiss
- Department of Research Design and Biostatistics, Sunnybrook Research Institute, University of Toronto, Canada
| | - Sandra E Black
- LC Campbell Cognitive Neurology Research Unit, University of Toronto, Canada; Heart and Stroke Foundation Centre for Stroke Recovery, University of Toronto, Canada; Brain Sciences Research Program, Sunnybrook Research Institute, University of Toronto, Canada; University of Toronto, Institute of Medical Sciences, University of Toronto, University of Toronto, Canada; Department of Medicine, Neurology, Sunnybrook Health Sciences Centre, University of Toronto, Canada
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