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Lee J, Kim GJ, Bashir S, Lee E, Ohn SH, Jung KI, Yoo WK. Heterogeneous Diffusion Metrics Patterns in Delayed Encephalopathy After Acute Carbon Monoxide Poisoning: A Case Report. BRAIN & NEUROREHABILITATION 2023; 16:e34. [PMID: 38047103 PMCID: PMC10689858 DOI: 10.12786/bn.2023.16.e34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 10/12/2023] [Accepted: 10/16/2023] [Indexed: 12/05/2023] Open
Abstract
Delayed encephalopathy (DE) following acute carbon monoxide (CO) poisoning is characterized by a wide range of neurological symptoms, including akinetic mutism, cognitive impairment, and gait disturbances. Herein, we reported the case of a 61-year-old patient with DE after acute CO poisoning, who displayed heterogeneous patterns of cortical and subcortical structural integrity on diffusion tensor imaging (DTI). Four distinct patterns of diffusion tensor metrics (fractional anisotropy [FA] and mean diffusivity [MD]) were observed in the patient compared to age-matched controls (a decrease in FA and an increase in MD, a decrease in FA only, an increase in MD only, and an increase in FA and MD). This study revealed heterogeneous patterns of cortical and subcortical damage associated with DE after CO poisoning, contributing to a deeper understanding of the diverse clinical symptoms observed in this patient.
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Affiliation(s)
- Jeongeun Lee
- Department of Physical Medicine and Rehabilitation, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Gyu Jin Kim
- Department of Physical Medicine and Rehabilitation, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Shahid Bashir
- Neuroscience Center, King Fahad Specialist Hospital Dammam, Dammam, Saudi Arabia
| | - Eunjee Lee
- Department of Physical Medicine and Rehabilitation, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Suk Hoon Ohn
- Department of Physical Medicine and Rehabilitation, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Kwang-Ik Jung
- Department of Physical Medicine and Rehabilitation, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Woo-Kyoung Yoo
- Department of Physical Medicine and Rehabilitation, Hallym University Sacred Heart Hospital, Anyang, Korea
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Pietrasik W, Cribben I, Olsen F, Malykhin N. Diffusion tensor imaging of superficial prefrontal white matter in healthy aging. Brain Res 2023; 1799:148152. [PMID: 36343726 DOI: 10.1016/j.brainres.2022.148152] [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: 06/06/2022] [Revised: 09/27/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
The prefrontal cortex (PFC) is a heterogenous structure that is highly susceptible to the effects of aging. Few studies have investigated age effects on the superficial white matter (WM) contained within the PFC using in-vivo magnetic resonance imaging (MRI). This study used diffusion tensor imaging (DTI) tractography to examine the effects of age, sex, and intracranial volume (ICV) on superficial WM within specific PFC subregions, and to model the relationships with age using higher order polynomial regression modelling. PFC WM of 140 healthy individuals, aged 18-85, was segmented into medial and lateral orbitofrontal, medial prefrontal, and dorsolateral prefrontal subregions. Differences due to age in microstructural parameters such as fractional anisotropy (FA), axial and radial diffusivities, and macrostructural measures of tract volumes, fiber counts, average fiber lengths, and average number of fibers per voxel were examined. We found that most prefrontal subregions demonstrated age effects, with decreases in FA, tract volume, and fiber counts, and increases in all diffusivity measures. Age relationships were mostly non-linear, with higher order regressions chosen in most cases. Declines in PFC FA began at the onset of adulthood while the greatest changes in diffusivity and volume did not occur until middle age. The effects of age were most prominent in medial tracts while the lateral orbitofrontal tracts were less affected. Significant effects of sex and ICV were also observed in certain parameters. The patterns mostly followed myelination order, with late-myelinating prefrontal subregions experiencing earlier and more pronounced age effects, further supporting the frontal theory of aging.
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Affiliation(s)
- Wojciech Pietrasik
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada; Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ivor Cribben
- Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Accounting & Business Analytics, Alberta School of Business, University of Alberta, Edmonton, Alberta, Canada
| | - Fraser Olsen
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nikolai Malykhin
- Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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Rogojin A, Gorbet DJ, Hawkins KM, Sergio LE. Differences in structural MRI and diffusion tensor imaging underlie visuomotor performance declines in older adults with an increased risk for Alzheimer's disease. Front Aging Neurosci 2023; 14:1054516. [PMID: 36711200 PMCID: PMC9877535 DOI: 10.3389/fnagi.2022.1054516] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/26/2022] [Indexed: 01/13/2023] Open
Abstract
Introduction Visuomotor impairments have been demonstrated in preclinical AD in individuals with a positive family history of dementia and APOE e4 carriers. Previous behavioral findings have also reported sex-differences in performance of visuomotor tasks involving a visual feedback reversal. The current study investigated the relationship between grey and white matter changes and non-standard visuomotor performance, as well as the effects of APOE status, family history of dementia, and sex on these brain-behavior relationships. Methods Older adults (n = 49) with no cognitive impairments completed non-standard visuomotor tasks involving a visual feedback reversal, plane-change, or combination of the two. Participants with a family history of dementia or who were APOE e4 carriers were considered at an increased risk for AD. T1-weighted anatomical scans were used to quantify grey matter volume and thickness, and diffusion tensor imaging measures were used to quantify white matter integrity. Results In APOE e4 carriers, grey and white matter structural measures were associated with visuomotor performance. Regression analyses showed that visuomotor deficits were predicted by lower grey matter thickness and volume in areas of the medial temporal lobe previously implicated in visuomotor control (entorhinal and parahippocampal cortices). This finding was replicated in the diffusion data, where regression analyses revealed that lower white matter integrity (lower FA, higher MD, higher RD, higher AxD) was a significant predictor of worse visuomotor performance in the forceps minor, forceps major, cingulum, inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), superior longitudinal fasciculus (SLF), and uncinate fasciculus (UF). Some of these tracts overlap with those important for visuomotor integration, namely the forceps minor, forceps major, SLF, IFOF, and ILF. Conclusion These findings suggest that measuring the dysfunction of brain networks underlying visuomotor control in early-stage AD may provide a novel behavioral target for dementia risk detection that is easily accessible, non-invasive, and cost-effective. The results also provide insight into the structural differences in inferior parietal lobule that may underlie previously reported sex-differences in performance of the visual feedback reversal task.
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Affiliation(s)
- Alica Rogojin
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada,Centre for Vision Research, York University, Toronto, ON, Canada,Vision: Science to Applications (VISTA) Program, York University, Toronto, ON, Canada
| | - Diana J. Gorbet
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada,Centre for Vision Research, York University, Toronto, ON, Canada
| | - Kara M. Hawkins
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Lauren E. Sergio
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada,Centre for Vision Research, York University, Toronto, ON, Canada,*Correspondence: Lauren E. Sergio, ✉
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Boban J, Thurnher MM, Boban N, Law M, Jahanshad N, Nir TM, Lendak DF, Kozic D. Gradient Patterns of Age-Related Diffusivity Changes in Cerebral White Matter. Front Neurol 2022; 13:870909. [PMID: 35720102 PMCID: PMC9201287 DOI: 10.3389/fneur.2022.870909] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/25/2022] [Indexed: 11/24/2022] Open
Abstract
The current concept of brain aging proposes three gradient patterns of changes in white matter that occur during healthy brain aging: antero-posterior, supero-inferior, and the myelodegeneration-retrogenesis (or the “last-in-first-out”) concept. The aim of this study was to correlate white matter diffusivity measures (fractional anisotropy-FA, mean diffusivity-MD, radial diffusivity-RD, and axial diffusivity-AD) in healthy volunteers with chronological age and education level, in order to potentially incorporate the findings with proposed patterns of physiological brain aging. The study was performed on 75 healthy participants of both sexes, with an average age of 37.32 ± 11.91 years underwent brain magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI). DTI was performed using tract-based spatial statistics (TBSS), with the analysis of four parameters: FA, MD, RD, and AD. Skeletonized measures were averaged in 29 regions of interest in white matter. Correlations between age and DTI measures and between education-level and DTI measures were performed using Pearson's correlation test. To correct for multiple comparisons, we applied a Bonferroni correction to the p-values. Significance was set at p ≤ 0.001. A significant negative correlation of FA with age was observed in posterior thalamic radiation (PTR) (p< 0.001). A significant positive correlation between age and MD was observed in sagittal stratum (SS) (p< 0.001), between age and RD in PTR, SS, and retrolenticular internal capsule (p< 0.001), and between age and AD in the body of the corpus callosum (p< 0.001). There were no significant correlations of DTI parameters with educational level. According to our study, RD showed the richest correlations with age, out of all DTI metrics. FA, MD, and RD showed significant changes in the diffusivity of projection fibers, while AD presented diffusivity changes in the commissural fibers. The observed heterogeneity in diffusivity changes across the brain cannot be explained by a single aging gradient pattern, since it seems that different patterns of degradation are true for different fiber tracts that no currently available theory can globally explain age-related changes in the brain. Additional factors, such as the effect of somatosensory decline, should be included as one of the important covariables to the existing patterns.
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Affiliation(s)
- Jasmina Boban
- Faculty of Medicine Novi Sad, Department of Radiology, University of Novi Sad, Novi Sad, Serbia
- Vojvodina Institute of Oncology, Center for Diagnostic Imaging, Sremska Kamenica, Serbia
- *Correspondence: Jasmina Boban
| | - Majda M. Thurnher
- Department for Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Nikola Boban
- Clinical Center of Vojvodina, Center for Radiology, Novi Sad, Serbia
| | - Meng Law
- Department for Neuroscience, The Alfred Centre, Central Clinical School, Monash University, Melbourne, VIC, United States
| | - Neda Jahanshad
- Imaging Genetics Center, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Marina del Rey, CA, United States
| | - Talia M. Nir
- Imaging Genetics Center, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Marina del Rey, CA, United States
| | - Dajana F. Lendak
- Faculty of Medicine Novi Sad, Department of Infectious Diseases, University of Novi Sad, Novi Sad, Serbia
- Clinical Center of Vojvodina, Clinic for Infectious Diseases, Novi Sad, Serbia
| | - Dusko Kozic
- Faculty of Medicine Novi Sad, Department of Radiology, University of Novi Sad, Novi Sad, Serbia
- Vojvodina Institute of Oncology, Center for Diagnostic Imaging, Sremska Kamenica, Serbia
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Berger M, Pirpamer L, Hofer E, Ropele S, Duering M, Gesierich B, Pasternak O, Enzinger C, Schmidt R, Koini M. Free water diffusion MRI and executive function with a speed component in healthy aging. Neuroimage 2022; 257:119303. [PMID: 35568345 PMCID: PMC9465649 DOI: 10.1016/j.neuroimage.2022.119303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/06/2022] [Accepted: 05/09/2022] [Indexed: 11/12/2022] Open
Abstract
Extracellular free water (FW) increases are suggested to better provide pathophysiological information in brain aging than conventional biomarkers such as fractional anisotropy. The aim of the present study was to determine the relationship between conventional biomarkers, FW in white matter hyperintensities (WMH), FW in normal appearing white matter (NAWM) and in white matter tracts and executive functions (EF) with a speed component in elderly persons. We examined 226 healthy elderly participants (median age 69.83 years, IQR: 56.99–74.42) who underwent brain MRI and neuropsychological examination. FW in WMH and in NAWM as well as FW corrected diffusion metrics and measures derived from conventional MRI (white matter hyperintensities, brain volume, lacunes) were used in partial correlation (adjusted for age) to assess their correlation with EF with a speed component. Random forest analysis was used to assess the relative importance of these variables as determinants. Lastly, linear regression analyses of FW in white matter tracts corrected for risk factors of cognitive and white matter deterioration, were used to examine the role of specific tracts on EF with a speed component, which were then ranked with random forest regression. Partial correlation analyses revealed that almost all imaging metrics showed a significant association with EF with a speed component (r = −0.213 – 0.266). Random forest regression highlighted FW in WMH and in NAWM as most important among all diffusion and structural MRI metrics. The fornix (R2=0.421, p = 0.018) and the corpus callosum (genu (R2 = 0.418, p = 0.021), prefrontal (R2 = 0.416, p = 0.026), premotor (R2 = 0.418, p = 0.021)) were associated with EF with a speed component in tract based regression analyses and had highest variables importance. In a normal aging population FW in WMH and NAWM is more closely related to EF with a speed component than standard DTI and brain structural measures. Higher amounts of FW in the fornix and the frontal part of the corpus callosum leads to deteriorating EF with a speed component.
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Affiliation(s)
- Martin Berger
- Department of Neurology, Division of Neurogeriatrics, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria
| | - Lukas Pirpamer
- Department of Neurology, Division of Neurogeriatrics, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria
| | - Edith Hofer
- Department of Neurology, Division of Neurogeriatrics, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria; Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria
| | - Stefan Ropele
- Department of Neurology, Division of Neurogeriatrics, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria
| | - Marco Duering
- Medical Image Analysis Center (MIAC AG) and Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Benno Gesierich
- Institute for Stroke and Dementia Research (ISD), University Hospital, Munich, Germany
| | - Ofer Pasternak
- Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Reinhold Schmidt
- Department of Neurology, Division of Neurogeriatrics, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria.
| | - Marisa Koini
- Department of Neurology, Division of Neurogeriatrics, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria
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Kannan L, Bhatt T, Zhang A, Ajilore O. Association of balance control mechanisms with brain structural integrity in older adults with mild cognitive impairment. Neurosci Lett 2022; 783:136699. [DOI: 10.1016/j.neulet.2022.136699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 10/18/2022]
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Andersson P, Li X, Persson J. The association between control of interference and white-matter integrity: A cross-sectional and longitudinal investigation. Neurobiol Aging 2022; 114:49-60. [DOI: 10.1016/j.neurobiolaging.2022.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/26/2022] [Accepted: 03/01/2022] [Indexed: 12/27/2022]
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Yeske B, Hou J, Adluru N, Nair VA, Prabhakaran V. Differences in Diffusion Tensor Imaging White Matter Integrity Related to Verbal Fluency Between Young and Old Adults. Front Aging Neurosci 2021; 13:750621. [PMID: 34880746 PMCID: PMC8647802 DOI: 10.3389/fnagi.2021.750621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 10/14/2021] [Indexed: 12/14/2022] Open
Abstract
Throughout adulthood, the brain undergoes an array of structural and functional changes during the typical aging process. These changes involve decreased brain volume, reduced synaptic density, and alterations in white matter (WM). Although there have been some previous neuroimaging studies that have measured the ability of adult language production and its correlations to brain function, structural gray matter volume, and functional differences between young and old adults, the structural role of WM in adult language production in individuals across the life span remains to be thoroughly elucidated. This study selected 38 young adults and 35 old adults for diffusion tensor imaging (DTI) and performed the Controlled Oral Word Association Test to assess verbal fluency (VF). Tract-Based Spatial Statistics were employed to evaluate the voxel-based group differences of diffusion metrics for the values of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and local diffusion homogeneity (LDH) in 12 WM regions of interest associated with language production. To investigate group differences on each DTI metric, an analysis of covariance (ANCOVA) controlling for sex and education level was performed, and the statistical threshold was considered at p < 0.00083 (0.05/60 labels) after Bonferroni correction for multiple comparisons. Significant differences in DTI metrics identified in the ANCOVA were used to perform correlation analyses with VF scores. Compared to the old adults, the young adults had significantly (1) increased FA values on the bilateral anterior corona radiata (ACR); (2) decreased MD values on the right ACR, but increased MD on the left uncinate fasciculus (UF); and (3) decreased RD on the bilateral ACR. There were no significant differences between the groups for AD or LDH. Moreover, the old adults had only a significant correlation between the VF score and the MD on the left UF. There were no significant correlations between VF score and DTI metrics in the young adults. This study adds to the growing body of research that WM areas involved in language production are sensitive to aging.
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Affiliation(s)
- Benjamin Yeske
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI, United States
| | - Jiancheng Hou
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI, United States
- Center for Cross-Strait Cultural Development, Fujian Normal University, Fuzhou, China
| | - Nagesh Adluru
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI, United States
- Waisman Center, University of Wisconsin–Madison, Madison, WI, United States
| | - Veena A. Nair
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI, United States
| | - Vivek Prabhakaran
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI, United States
- Department of Psychology, Department of Psychiatry, University of Wisconsin–Madison, Madison, WI, United States
- Neuroscience Training Program, University of Wisconsin–Madison, Madison, WI, United States
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Moon Y, Yang JJ, Lee WJ, Lee JY, Kim YJ, Lim HW. In vivo Analysis of Normal Optic Nerve in an Elderly Population Using Diffusion Magnetic Resonance Imaging Tractography. Front Neurol 2021; 12:680488. [PMID: 34630272 PMCID: PMC8498569 DOI: 10.3389/fneur.2021.680488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To quantitatively investigate the microstructural properties of the optic nerve (ON) in vivo using diffusion magnetic resonance imaging (dMRI) tractography in an elderly population and to determine the differences between the ON diffusion properties stratified by basic demographics. Methods: We measured fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) of the intraorbital ON in cognitively normal controls selected from the Alzheimer's Disease Neuroimaging Initiative 3 database (n =104; mean age = 73. 8 ± 8.1 years) using dMRI probabilistic tractography and evaluated the correlation between diffusion parameters and demographic factors. Diffusion parameters were measured in 20 equidistant nodes along the tract, and the data from proximal 70% (14 nodes) of the intraorbital ON were averaged. Results: The mean FA of the intraorbital ON was 0.392 ± 0.063, and the mean MD was 1.163 ± 0.165 μm2/s. The mean RD was 0.882 ± 0.152 μm2/s, and the mean AD was 1.693 ± 0.183 μm2/s. The multiple linear regression model showed a negative correlation between FA and age. FA in females was significantly higher than males, whereas RD in female was significantly lower. Conclusions: We measured the diffusion properties of the intraorbital ON using dMRI tractography in an elderly cognitively normal population. The diffusion properties detected by dMRI tractography may substantially reflect the microstructure of the ON.
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Affiliation(s)
- Yeji Moon
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.,Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, South Korea
| | - Jin-Ju Yang
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, South Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, South Korea
| | - Won June Lee
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, South Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, South Korea
| | - Ji Young Lee
- Hanyang Vision Research Center, Hanyang University, Seoul, South Korea.,Department of Radiology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, South Korea
| | - Yu Jeong Kim
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, South Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, South Korea
| | - Han Woong Lim
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, South Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, South Korea
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Molloy CJ, Nugent S, Bokde ALW. Alterations in Diffusion Measures of White Matter Integrity Associated with Healthy Aging. J Gerontol A Biol Sci Med Sci 2021; 76:945-954. [PMID: 31830253 DOI: 10.1093/gerona/glz289] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
This study aimed to characterize age-related white matter changes by evaluating patterns of overlap between the linear association of age with fractional anisotropy (FA) with mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Specifically, we assessed patterns of overlap between diffusion measures of normal appearing white matter by covarying for white matter hyperintensity (WMH) load, as WMHs are thought to increase with age and impact diffusion measures. Seventy-nine healthy adults aged between 18 and 75 years took part in the study. Diffusion tensor imaging (DTI) data were based on 61 directions acquired with a b-value of 2,000. We found five main patterns of overlap: FA alone (15.95%); FA and RD (31.90%); FA and AD (12.99%); FA, RD, and AD (27.93%); and FA, RD, and MD (8.79%). We showed that cognitively healthy aging adults had low WMH load, which subsequently had minimal effect on diffusion measures. We discuss how patterns of overlap may reflect underlying biological changes observed with aging such as loss of myelination, axonal damage, as well as mild microstructural and chronic white matter impairments. This study contributes to understanding the underlying causes of degeneration in specific regions of the brain and highlights the importance of considering the impact of WMHs in aging studies of white matter.
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Affiliation(s)
- Ciara J Molloy
- Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Ireland
- Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Sinead Nugent
- Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Ireland
- Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Arun L W Bokde
- Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Ireland
- Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
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Vakhtin AA, Zhang Y, Wintermark M, Ashford JW, Furst AJ. Distant histories of mild traumatic brain injury exacerbate age-related differences in white matter properties. Neurobiol Aging 2021; 107:30-41. [PMID: 34371285 DOI: 10.1016/j.neurobiolaging.2021.07.002] [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: 03/02/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 10/20/2022]
Abstract
We examined associations of distant histories of mild traumatic brain injury (mTBI) with non-linear and linear trajectories of white matter (WM) properties across a wide age range (23-77). Diffusion tensor imaging (DTI) data obtained from 171 Veterans with histories of clinically diagnosed mTBIs and 115 controls were subjected to tractography, isolating 20 major WM tracts. Non-linear and linear effects of age on each tract's diffusion properties were examined in terms of their interactions with group (mTBI and control). The non-linear model revealed 7 tracts in which the mTBI group's DTI metrics rapidly deviated from control trajectories in middle and late adulthoods, despite the injuries having occurred in the late 20s, on average. In contrast, no interactions between prior injuries and age were detected when examining linear trajectories. Distant mTBIs may thus accelerate normal age-related trajectories of WM degeneration much later in life. As such, life-long histories of head trauma should be assessed in all patients in their mid-to-late adulthoods, whether neurologically healthy or presenting with seemingly unrelated neuropathology.
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Affiliation(s)
- Andrei A Vakhtin
- The Mind Research Network/Lovelace Biomedical and Environmental Research Institute, Albuquerque, NM, USA.
| | - Yu Zhang
- War Related Illness and Injury Study Center (WRIISC), Palo Alto Veterans Affairs Hospital, Palo Alto, CA, USA
| | - Max Wintermark
- Neuroradiology, Stanford University School of Medicine, Stanford, CA, USA
| | - John W Ashford
- War Related Illness and Injury Study Center (WRIISC), Palo Alto Veterans Affairs Hospital, Palo Alto, CA, USA; Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Ansgar J Furst
- War Related Illness and Injury Study Center (WRIISC), Palo Alto Veterans Affairs Hospital, Palo Alto, CA, USA; Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA; Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA; Polytrauma System of Care, Palo Alto Veterans Affairs Hospital, Palo Alto, CA, USA
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12
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Ouyang Y, Cui D, Yuan Z, Liu Z, Jiao Q, Yin T, Qiu J. Analysis of Age-Related White Matter Microstructures Based on Diffusion Tensor Imaging. Front Aging Neurosci 2021; 13:664911. [PMID: 34262444 PMCID: PMC8273390 DOI: 10.3389/fnagi.2021.664911] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/14/2021] [Indexed: 12/04/2022] Open
Abstract
Population aging has become a serious social problem. Accordingly, many researches are focusing on changes in brains of the elderly. In this study, we used multiple parameters to analyze age-related changes in white matter fibers. A sample cohort of 58 individuals was divided into young and middle-age groups and tract-based spatial statistics (TBSS) were used to analyze the differences in fractional anisotropy (FA), mean diffusion (MD), axial diffusion (AD), and radial diffusion (RD) between the two groups. Deterministic fiber tracking was used to investigate the correlation between fiber number and fiber length with age. The TBSS analysis revealed significant differences in FA, MD, AD, and RD in multiple white matter fibers between the two groups. In the middle-age group FA and AD were lower than in young people, whereas the MD and RD values were higher. Deterministic fiber tracking showed that the fiber length of some fibers correlated positively with age. These fibers were observed in the splenium of corpus callosum (SCC), the posterior limb of internal capsule (PLIC), the right posterior corona radiata (PCR_R), the anterior corona radiata (ACR), the left posterior thalamic radiation (include optic radiation; PTR_L), and the left superior longitudinal fasciculus (SLF_L), among others. The results showed that the SCC, PLIC, PCR_R, ACR, PTR_L, and SLF_L significantly differed between young and middle-age people. Therefore, we believe that these fibers could be used as image markers of age-related white matter changes.
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Affiliation(s)
- Yahui Ouyang
- Medical Engineering and Technology Research Center, Shandong First Medical University (Shandong Academy of Medical Sciences), Tai'an, China.,College of Radiology, Shandong First Medical University (Shandong Academy of Medical Sciences), Tai'an, China
| | - Dong Cui
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Zilong Yuan
- Department of Radiology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhipeng Liu
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Qing Jiao
- College of Radiology, Shandong First Medical University (Shandong Academy of Medical Sciences), Tai'an, China
| | - Tao Yin
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Jianfeng Qiu
- Medical Engineering and Technology Research Center, Shandong First Medical University (Shandong Academy of Medical Sciences), Tai'an, China.,College of Radiology, Shandong First Medical University (Shandong Academy of Medical Sciences), Tai'an, China
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13
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Coelho A, Fernandes HM, Magalhães R, Moreira PS, Marques P, Soares JM, Amorim L, Portugal-Nunes C, Castanho T, Santos NC, Sousa N. Signatures of white-matter microstructure degradation during aging and its association with cognitive status. Sci Rep 2021; 11:4517. [PMID: 33633204 PMCID: PMC7907273 DOI: 10.1038/s41598-021-83983-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 02/01/2021] [Indexed: 11/09/2022] Open
Abstract
Previous studies have shown an association between cognitive decline and white matter integrity in aging. This led to the formulation of a "disconnection hypothesis" in the aging-brain, which states that the disruption in cortical network communication may explain the cognitive decline during aging. Although some longitudinal studies have already investigated the changes occurring in white matter microstructure, most focused on specific white matter tracts. Our study aims to characterize the longitudinal whole-brain signatures of white matter microstructural change during aging. Furthermore, we assessed the relationship between distinct longitudinal alterations in white matter integrity and cognition. White matter microstructural properties were estimated from diffusion magnetic resonance imaging, and cognitive status characterized from extensive neurocognitive testing. The same individuals were evaluated at two timepoints, with a mean interval time of 52.8 months (SD = 7.24) between first and last assessment. Our results show that age is associated with a decline in cognitive performance and a degradation in white matter integrity. Additionally, significant associations were found between diffusion measures and different cognitive dimensions (memory, executive function and general cognition). Overall, these results suggest that age-related cognitive decline is related to white matter alterations, and thus give support to the "disconnected hypothesis" of the aging brain.
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Affiliation(s)
- Ana Coelho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Henrique M Fernandes
- Center for Music in the Brain (MIB), Aarhus University, Aarhus, Denmark
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Ricardo Magalhães
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Pedro Silva Moreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Paulo Marques
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - José M Soares
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Liliana Amorim
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Carlos Portugal-Nunes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Teresa Castanho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Nadine Correia Santos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.
- ICVS/3B's, PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal.
- Clinical Academic Center-Braga, 4710-057, Braga, Portugal.
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Etherton MR, Wu O, Giese AK, Rost NS. Normal-appearing white matter microstructural injury is associated with white matter hyperintensity burden in acute ischemic stroke. Int J Stroke 2019; 16:184-191. [PMID: 31847795 DOI: 10.1177/1747493019895707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND White matter hyperintensity of presumed vascular origin is a risk factor for poor stroke outcomes. In patients with acute ischemic stroke, however, the in vivo mechanisms of white matter microstructural injury are less clear. AIMS To characterize the directional diffusivity components in normal-appearing white matter and white matter hyperintensity in acute ischemic stroke patients. METHODS A retrospective analysis was performed on a cohort of patients with acute ischemic stroke and brain magnetic resonance imaging with diffusion tensor imaging sequences acquired within 48 h of admission. White matter hyperintensity volume was measured in a semi-automated manner. Median fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity values were calculated within normal-appearing white matter and white matter hyperintensity in the hemisphere contralateral to the acute infarct. Linear regression analysis was performed to evaluate predictors of white matter hyperintensity volume and normal-appearing white matter diffusivity metrics. RESULTS In 319 patients, mean age was 64.9 ± 15.9 years. White matter hyperintensity volume was 6.33 cm3 (interquartile range 3.0-12.6 cm3). Axial and radial diffusivity were significantly increased in white matter hyperintensity compared to normal-appearing white matter. In multivariable linear regression, age (β = 0.20, P = 0.003) and normal-appearing white matter axial diffusivity (β = 37.9, P < 0.001) were independently associated with white matter hyperintensity volume. Subsequent analysis demonstrated that increasing age (β = 0.004, P < 0.001) and admission diastolic blood pressure (β = 0.001, P = 0.02) were independent predictors of normal-appearing white matter axial diffusivity in multivariable linear regression. CONCLUSIONS Normal-appearing white matter axial diffusivity increases with age and is an independent predictor of white matter hyperintensity volume in acute ischemic stroke.
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Affiliation(s)
- Mark R Etherton
- Department of Neurology, J. Philip Kistler Stroke Research Center, 2348Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Ona Wu
- Department of Neurology, J. Philip Kistler Stroke Research Center, 2348Massachusetts General Hospital and Harvard Medical School, Boston, USA.,Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, 2348Massachusetts General Hospital, Boston, USA
| | - Anne-Katrin Giese
- Department of Neurology, J. Philip Kistler Stroke Research Center, 2348Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Natalia S Rost
- Department of Neurology, J. Philip Kistler Stroke Research Center, 2348Massachusetts General Hospital and Harvard Medical School, Boston, USA
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15
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Linking the impact of aging on visual short-term memory capacity with changes in the structural connectivity of posterior thalamus to occipital cortices. Neuroimage 2019; 208:116440. [PMID: 31841682 DOI: 10.1016/j.neuroimage.2019.116440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/25/2019] [Accepted: 12/03/2019] [Indexed: 12/31/2022] Open
Abstract
Aging impacts both visual short-term memory (vSTM) capacity and thalamo-cortical connectivity. According to the Neural Theory of Visual Attention, vSTM depends on the structural connectivity between posterior thalamus and visual occipital cortices (PT-OC). We tested whether aging modifies the association between vSTM capacity and PT-OC structural connectivity. To do so, 66 individuals aged 20-77 years were assessed by diffusion-weighted imaging used for probabilistic tractography and performed a psychophysical whole-report task of briefly presented letter arrays, from which vSTM capacity estimates were derived. We found reduced vSTM capacity, and aberrant PT-OC connection probability in aging. Critically, age modified the relationship between vSTM capacity and PT-OC connection probability: in younger adults, vSTM capacity was negatively correlated with PT-OC connection probability while in older adults, this association was positive. Furthermore, age modified the microstructure of PT-OC tracts suggesting that the inversion of the association between PT-OC connection probability and vSTM capacity with aging might reflect age-related changes in white-matter properties. Accordingly, our results demonstrate that age-related differences in vSTM capacity links with the microstructure and connectivity of PT-OC tracts.
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16
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Vangberg TR, Eikenes L, Håberg AK. The effect of white matter hyperintensities on regional brain volumes and white matter microstructure, a population-based study in HUNT. Neuroimage 2019; 203:116158. [PMID: 31493533 DOI: 10.1016/j.neuroimage.2019.116158] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/03/2019] [Accepted: 09/02/2019] [Indexed: 12/19/2022] Open
Abstract
Even though age-related white matter hyperintensities (WMH) begin to emerge in middle age, their effect on brain micro- and macrostructure in this age group is not fully elucidated. We have examined how presence of WMH and load of WMH affect regional brain volumes and microstructure in a validated, representative general population sample of 873 individuals between 50 and 66 years. Presence of WMH was determined as Fazakas grade ≥1. WMH load was WMH volume from manual tracing of WMHs divided on intracranial volume. The impact of age appropriate WMH (Fazakas grade 1) on the brain was also investigated. Major novel findings were that even the age appropriate WMH group had widespread macro- and microstructural changes in gray and white matter, showing that the mere presence of WMH, not just WMH load is an important clinical indicator of brain health. With increasing WMH load, structural changes spread centrifugally. Further, we found three major patterns of FA and MD changes related to increasing WMH load, demonstrating a heterogeneous effect on white matter microstructure, where distinct patterns were found in the proximity of the lesions, in deep white matter and in white matter near the cortex. This study also raises several questions about the onset of WMH related pathology, in particular, whether some of the aberrant brain structural and microstructural findings are present before the emergence of WMH. We also found, similar to other studies, that WMH risk factors had low explanatory power for WMH, making it unclear which factors lead to WMH.
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Affiliation(s)
- Torgil Riise Vangberg
- Medical Imaging Research Group, Department of Clinical Medicine, UiT the Arctic University of Norway, Tromsø, Norway; PET Center, University Hospital North Norway, Tromsø, Norway
| | - Live Eikenes
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Asta K Håberg
- Department of Radiology and Nuclear Medicine, St. Olav University Hospital, Trondheim, Norway; Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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17
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Fan Q, Tian Q, Ohringer NA, Nummenmaa A, Witzel T, Tobyne SM, Klawiter EC, Mekkaoui C, Rosen BR, Wald LL, Salat DH, Huang SY. Age-related alterations in axonal microstructure in the corpus callosum measured by high-gradient diffusion MRI. Neuroimage 2019; 191:325-336. [PMID: 30790671 DOI: 10.1016/j.neuroimage.2019.02.036] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/26/2019] [Accepted: 02/14/2019] [Indexed: 12/14/2022] Open
Abstract
Cerebral white matter exhibits age-related degenerative changes during the course of normal aging, including decreases in axon density and alterations in axonal structure. Noninvasive approaches to measure these microstructural alterations throughout the lifespan would be invaluable for understanding the substrate and regional variability of age-related white matter degeneration. Recent advances in diffusion magnetic resonance imaging (MRI) have leveraged high gradient strengths to increase sensitivity toward axonal size and density in the living human brain. Here, we examined the relationship between age and indices of axon diameter and packing density using high-gradient strength diffusion MRI in 36 healthy adults (aged 22-72) in well-defined central white matter tracts in the brain. A recently validated method for inferring the effective axonal compartment size and packing density from diffusion MRI measurements acquired with 300 mT/m maximum gradient strength was applied to the in vivo human brain to obtain indices of axon diameter and density in the corpus callosum, its sub-regions, and adjacent anterior and posterior fibers in the forceps minor and forceps major. The relationships between the axonal metrics, corpus callosum area and regional gray matter volume were also explored. Results revealed a significant increase in axon diameter index with advancing age in the whole corpus callosum. Similar analyses in sub-regions of the corpus callosum showed that age-related alterations in axon diameter index and axon density were most pronounced in the genu of the corpus callosum and relatively absent in the splenium, in keeping with findings from previous histological studies. The significance of these correlations was mirrored in the forceps minor and forceps major, consistent with previously reported decreases in FA in the forceps minor but not in the forceps major with age. Alterations in the axonal imaging metrics paralleled decreases in corpus callosum area and regional gray matter volume with age. Among older adults, results from cognitive testing suggested an association between larger effective compartment size in the corpus callosum, particularly within the genu of the corpus callosum, and lower scores on the Montreal Cognitive Assessment, largely driven by deficits in short-term memory. The current study suggests that high-gradient diffusion MRI may be sensitive to the axonal substrate of age-related white matter degeneration reflected in traditional DTI metrics and provides further evidence for regionally selective alterations in white matter microstructure with advancing age.
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Affiliation(s)
- Qiuyun Fan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Ned A Ohringer
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Aapo Nummenmaa
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Thomas Witzel
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Sean M Tobyne
- Harvard Medical School, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Eric C Klawiter
- Harvard Medical School, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Choukri Mekkaoui
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Bruce R Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lawrence L Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David H Salat
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Susie Y Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
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18
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Guerreri M, Palombo M, Caporale A, Fasano F, Macaluso E, Bozzali M, Capuani S. Age-related microstructural and physiological changes in normal brain measured by MRI γ-metrics derived from anomalous diffusion signal representation. Neuroimage 2018; 188:654-667. [PMID: 30583064 DOI: 10.1016/j.neuroimage.2018.12.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/11/2018] [Accepted: 12/20/2018] [Indexed: 12/29/2022] Open
Abstract
Nowadays, increasing longevity associated with declining cerebral nervous system functions, suggests the need for continued development of new imaging contrast mechanisms to support the differential diagnosis of age-related decline. In our previous papers, we developed a new imaging contrast metrics derived from anomalous diffusion signal representation and obtained from diffusion-weighted (DW) data collected by varying diffusion gradient strengths. Recently, we highlighted that the new metrics, named γ-metrics, depended on the local inhomogeneity due to differences in magnetic susceptibility between tissues and diffusion compartments in young healthy subjects, thus providing information about myelin orientation and iron content within cerebral regions. The major structural modifications occurring in brain aging are myelinated fibers damage in nerve fibers and iron accumulation in gray matter nuclei. Therefore, we investigated the potential of γ-metrics in relation to other conventional diffusion metrics such as DTI, DKI and NODDI in detecting age-related structural changes in white matter (WM) and subcortical gray matter (scGM). DW-images were acquired in 32 healthy subjects, adults and elderly (age range 20-77 years) using 3.0T and 12 b-values up to 5000 s/mm2. Association between diffusion metrics and subjects' age was assessed using linear regression. A decline in mean γ (Mγ) in the scGM and a complementary increase in radial γ (γ⊥) in frontal WM, genu of corpus callosum and anterior corona radiata with advancing age were found. We suggested that the increase in γ⊥ might reflect declined myelin density, and Mγ decrease might mirror iron accumulation. An increase in D// and a decrease in the orientation dispersion index (ODI) were associated with axonal loss in the pyramidal tracts, while their inverted trends within the thalamus were thought to be linked to reduced architectural complexity of nerve fibers. γ-metrics together with conventional diffusion-metrics can more comprehensively characterize the complex mechanisms underlining age-related changes than conventional diffusion techniques alone.
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Affiliation(s)
- Michele Guerreri
- SAIMLAL Department, Sapienza, Piazzale Aldo Moro, 5, 00185, Roma, RM, Italy; Institute for Complex Systems, CNR, Rome, Italy.
| | - Marco Palombo
- Institute for Complex Systems, CNR, Rome, Italy; Department of Computer Science & Centre for Medical Image Computing, University College London, London, United Kingdom
| | - Alessandra Caporale
- Institute for Complex Systems, CNR, Rome, Italy; Laboratory for Structural, Physiologic and Functional Imaging, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Marco Bozzali
- Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy
| | - Silvia Capuani
- Institute for Complex Systems, CNR, Rome, Italy; Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy
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19
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Effects of low-level sarin and cyclosarin exposure on hippocampal microstructure in Gulf War Veterans. Neurotoxicol Teratol 2018; 68:36-46. [PMID: 29733897 DOI: 10.1016/j.ntt.2018.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/13/2018] [Accepted: 05/02/2018] [Indexed: 12/18/2022]
Abstract
In early March 1991, shortly after the end of the Gulf War (GW), a munitions dump was destroyed at Khamisiyah, Iraq. Later, in 1996, the dump was found to have contained the organophosphorus (OP) nerve agents sarin and cyclosarin. We previously reported evidence of smaller hippocampal volumes in GW veterans with predicted exposure to the Khamisiyah plume compared to unexposed GW veterans. To investigate whether these macroscopic hippocampal volume changes are accompanied by microstructural alterations in the hippocampus, the current study acquired diffusion-tensor imaging (DTI), T1-, and T2-weighted images from 170 GW veterans (mean age: 53 ± 7 years), 81 of whom had predicted exposure to the Khamisiyah plume according to Department of Defense (DOD) plume modeling. We examined fractional anisotropy (FA), mean diffusivity (MD), and grey matter (GM) density from a hippocampal region of interest (ROI). Results indicate that, even after accounting for total hippocampal GM density (or hippocampal volume), age, sex, apolipoprotein ε4 genotype, and potential confounding OP pesticide exposures, hippocampal MD significantly predicted Khamisiyah exposure status (model p = 0.005, R2 = 0.215, standardized coefficient β = 0.26, t = 2.85). Hippocampal MD was also inversely correlated with verbal memory learning performance in the entire study sample (p = 0.001). There were no differences in hippocampal FA or GM density; however, veterans with predicted Khamisiyah exposure had smaller hippocampal volumes compared to unexposed veterans. Because MD is sensitive to general microstructural disruptions that lead to increased extracellular spaces due to neuronal death, inflammation and gliosis, and/or to axonal loss or demyelination, these findings suggest that low-level exposure to the Khamisiyah plume has a detrimental, lasting effects on both macro- and micro-structure of the hippocampus.
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20
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Serbruyns L, Leunissen I, van Ruitenbeek P, Pauwels L, Caeyenberghs K, Solesio-Jofre E, Geurts M, Cuypers K, Meesen RL, Sunaert S, Leemans A, Swinnen SP. Alterations in brain white matter contributing to age-related slowing of task switching performance: The role of radial diffusivity and magnetization transfer ratio. Hum Brain Mapp 2018; 37:4084-4098. [PMID: 27571231 DOI: 10.1002/hbm.23297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 05/30/2016] [Accepted: 06/19/2016] [Indexed: 12/26/2022] Open
Abstract
Successfully switching between tasks is critical in many daily activities. Age-related slowing of this switching behavior has been documented extensively, but the underlying neural mechanisms remain unclear. Here, we investigated the contribution of brain white matter changes associated with myelin alterations to age-related slowing of switching performance. Diffusion tensor imaging derived radial diffusivity (RD) and magnetization transfer imaging derived magnetization transfer ratio (MTR) were selected as myelin sensitive measures. These metrics were studied in relation to mixing cost (i.e., the increase in reaction time during task blocks that require task switching) on a local-global switching task in young (n = 24) and older (n = 22) adults. Results showed that higher age was associated with widespread increases in RD and decreases in MTR, indicative of white matter deterioration, possibly due to demyelination. Older adults also showed a higher mixing cost, implying slowing of switching performance. Finally, mediation analyses demonstrated that decreases in MTR of the bilateral superior corona radiata contributed to the observed slowing of switching performance with increasing age. These findings provide evidence for a role of cortico-subcortical white matter changes in task switching performance deterioration with healthy aging. Hum Brain Mapp 37:4084-4098, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Leen Serbruyns
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Inge Leunissen
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Peter van Ruitenbeek
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Lisa Pauwels
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Karen Caeyenberghs
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.,School of Psychology, Faculty of Health Sciences, Australian Catholic University, Australia
| | - Elena Solesio-Jofre
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Monique Geurts
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Koen Cuypers
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.,REVAL Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Raf L Meesen
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.,REVAL Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Stefan Sunaert
- Medical Imaging Research Center, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Alexander Leemans
- Image Sciences Institute, University Medical Center Utrecht, The Netherlands
| | - Stephan P Swinnen
- Motor Control Laboratory, Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Leuven, Belgium. .,KU Leuven, Leuven Research Institute for Neuroscience & Disease (LIND), Belgium.
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Lee Masson H, Kang HM, Petit L, Wallraven C. Neuroanatomical correlates of haptic object processing: combined evidence from tractography and functional neuroimaging. Brain Struct Funct 2017; 223:619-633. [PMID: 28905126 DOI: 10.1007/s00429-017-1510-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 09/05/2017] [Indexed: 11/25/2022]
Abstract
Touch delivers a wealth of information already from birth, helping infants to acquire knowledge about a variety of important object properties using their hands. Despite the fact that we are touch experts as much as we are visual experts, surprisingly, little is known how our perceptual ability in touch is linked to either functional or structural aspects of the brain. The present study, therefore, investigates and identifies neuroanatomical correlates of haptic perceptual performance using a novel, multi-modal approach. For this, participants' performance in a difficult shape categorization task was first measured in the haptic domain. Using a multi-modal functional magnetic resonance imaging and diffusion-weighted magnetic resonance imaging analysis pipeline, functionally defined and anatomically constrained white-matter pathways were extracted and their microstructural characteristics correlated with individual variability in haptic categorization performance. Controlling for the effects of age, total intracranial volume and head movements in the regression model, haptic performance was found to correlate significantly with higher axial diffusivity in functionally defined superior longitudinal fasciculus (fSLF) linking frontal and parietal areas. These results were further localized in specific sub-parts of fSLF. Using additional data from a second group of participants, who first learned the categories in the visual domain and then transferred to the haptic domain, haptic performance correlates were obtained in the functionally defined inferior longitudinal fasciculus. Our results implicate SLF linking frontal and parietal areas as an important white-matter track in processing touch-specific information during object processing, whereas ILF relays visually learned information during haptic processing. Taken together, the present results chart for the first time potential neuroanatomical correlates and interactions of touch-related object processing.
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Affiliation(s)
- Haemy Lee Masson
- Department of Brain and Cognition, KU Leuven, 3000, Louvain, Belgium
| | - Hyeok-Mook Kang
- Department of Brain and Cognitive Engineering, Korea University, Seoul, 136-713, Korea
| | - Laurent Petit
- Groupe d'Imagerie Neurofonctionnelle, Institut Des Maladies Neurodégénératives, UMR 5293, CNRS, CEA University of Bordeaux, Bordeaux, France
| | - Christian Wallraven
- Department of Brain and Cognitive Engineering, Korea University, Seoul, 136-713, Korea.
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Tian L, Ma L. Microstructural Changes of the Human Brain from Early to Mid-Adulthood. Front Hum Neurosci 2017; 11:393. [PMID: 28824398 PMCID: PMC5545923 DOI: 10.3389/fnhum.2017.00393] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 07/17/2017] [Indexed: 11/29/2022] Open
Abstract
Despite numerous studies on the microstructural changes of the human brain throughout life, we have indeed little direct knowledge about the changes from early to mid-adulthood. The aim of this study was to investigate the microstructural changes of the human brain from early to mid-adulthood. We performed two sets of analyses based on the diffusion tensor imaging (DTI) data of 111 adults aged 18–55 years. Specifically, we first correlated age with skeletonized fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) at global and regional level, and then estimated individuals’ ages based on each DTI metric using elastic net, a kind of multivariate pattern analysis (MVPA) method that aims at selecting the model that achieves the best trade-off between goodness of fit and model complexity. We observed statistically significant negative age-vs-FA correlations and relatively less changes of MD. The negative age-vs-FA correlations were associated with negative age-vs-AD and positive age-vs-RD correlations. Regional negative age-vs-FA correlations were observed in the bilateral genu of the corpus callosum (CCg), the corticospinal tract (CST), the fornix and several other tracts, and these negative correlations may indicate the earlier changes of the fibers with aging. In brain age estimation, the chronological-vs-estimated-age correlations based on FA, MD, AD and RD were R = 0.62, 0.44, 0.63 and 0.69 (P = 0.002, 0.008, 0.002 and 0.002 based on 500 permutations), respectively, and these results indicate that even the microstructural changes from early to mid-adulthood alone are sufficiently specific to decode individuals’ ages. Overall, the current results not only demonstrated statistically significant FA decreases from early to mid-adulthood and clarified the driving factors of the FA decreases (RD increases and AD decreases, in contrast to increases of both measures in late-adulthood), but highlighted the necessity of considering age effects in related studies.
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Affiliation(s)
- Lixia Tian
- School of Computer and Information Technology, Beijing Jiaotong UniversityBeijing, China
| | - Lin Ma
- School of Computer and Information Technology, Beijing Jiaotong UniversityBeijing, China
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Aging-Resilient Associations between the Arcuate Fasciculus and Vocabulary Knowledge: Microstructure or Morphology? J Neurosci 2017; 36:7210-22. [PMID: 27383595 DOI: 10.1523/jneurosci.4342-15.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 05/27/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Vocabulary knowledge is one of the few cognitive functions that is relatively preserved in older adults, but the reasons for this relative preservation have not been well delineated. We tested the hypothesis that individual differences in vocabulary knowledge are influenced by arcuate fasciculus macrostructure (i.e., shape and volume) properties that remain stable during the aging process, rather than white matter microstructure that demonstrates age-related declines. Vocabulary was not associated with age compared to pronounced age-related declines in cognitive processing speed across 106 healthy adults (19.92-88.29 years) who participated in this neuroimaging experiment. Fractional anisotropy in the left arcuate fasciculus was significantly related to individual variability in vocabulary. This effect was present despite marked age-related differences in a T1-weighted/T2-weighted ratio (T1w/T2w) estimate of myelin that were observed throughout the left arcuate fasciculus and associated with age-related differences in cognitive processing speed. However, atypical patterns of arcuate fasciculus morphology or macrostructure were associated with decreased vocabulary knowledge. These results suggest that deterioration of tissue in the arcuate fasciculus occurs with normal aging, while having limited impact on tract organization that underlies individual differences in the acquisition and retrieval of lexical and semantic information. SIGNIFICANCE STATEMENT Vocabulary knowledge is resilient to widespread age-related declines in brain structure that limit other cognitive functions. We tested the hypothesis that arcuate fasciculus morphology, which supports the development of reading skills that bolster vocabulary, could explain this relative preservation. We disentangled (1) the effects of age-related declines in arcuate microstructure (mean diffusivity; myelin content estimate) that predicted cognitive processing speed but not vocabulary, from (2) relatively stable arcuate macrostructure (shape/volume) that explained significant variance in an age-independent association between fractional anisotropy and vocabulary. This latter result may reflect differences in fiber trajectory and organization that are resilient to aging. We propose that developmental sculpting of the arcuate fasciculus determines acquisition, storage, and access of lexical information across the adult lifespan.
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Variation on the dopamine D2 receptor gene (DRD2) is associated with basal ganglia-to-frontal structural connectivity. Neuroimage 2017; 155:473-479. [DOI: 10.1016/j.neuroimage.2017.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/31/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022] Open
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25
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Age-related white-matter correlates of motor sequence learning and consolidation. Neurobiol Aging 2016; 48:13-22. [DOI: 10.1016/j.neurobiolaging.2016.08.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 07/22/2016] [Accepted: 08/09/2016] [Indexed: 01/28/2023]
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Lawrenz M, Brassen S, Finsterbusch J. Microscopic diffusion anisotropy in the human brain: Age-related changes. Neuroimage 2016; 141:313-325. [DOI: 10.1016/j.neuroimage.2016.07.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/18/2016] [Accepted: 07/13/2016] [Indexed: 11/16/2022] Open
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Pini L, Pievani M, Bocchetta M, Altomare D, Bosco P, Cavedo E, Galluzzi S, Marizzoni M, Frisoni GB. Brain atrophy in Alzheimer's Disease and aging. Ageing Res Rev 2016; 30:25-48. [PMID: 26827786 DOI: 10.1016/j.arr.2016.01.002] [Citation(s) in RCA: 438] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 01/22/2023]
Abstract
Thanks to its safety and accessibility, magnetic resonance imaging (MRI) is extensively used in clinical routine and research field, largely contributing to our understanding of the pathophysiology of neurodegenerative disorders such as Alzheimer's disease (AD). This review aims to provide a comprehensive overview of the main findings in AD and normal aging over the past twenty years, focusing on the patterns of gray and white matter changes assessed in vivo using MRI. Major progresses in the field concern the segmentation of the hippocampus with novel manual and automatic segmentation approaches, which might soon enable to assess also hippocampal subfields. Advancements in quantification of hippocampal volumetry might pave the way to its broader use as outcome marker in AD clinical trials. Patterns of cortical atrophy have been shown to accurately track disease progression and seem promising in distinguishing among AD subtypes. Disease progression has also been associated with changes in white matter tracts. Recent studies have investigated two areas often overlooked in AD, such as the striatum and basal forebrain, reporting significant atrophy, although the impact of these changes on cognition is still unclear. Future integration of different MRI modalities may further advance the field by providing more powerful biomarkers of disease onset and progression.
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Affiliation(s)
- Lorenzo Pini
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy; Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Michela Pievani
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy
| | - Martina Bocchetta
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy; Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, London, UK
| | - Daniele Altomare
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy; Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Paolo Bosco
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy
| | - Enrica Cavedo
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy; Sorbonne Universités, Université Pierre et Marie Curie, Paris 06, Institut de la Mémoire et de la Maladie d'Alzheimer (IM2A) Hôpital de la Pitié-Salpétrière & Institut du Cerveau et de la Moelle épinière (ICM), UMR S 1127, Hôpital de la Pitié-Salpétrière Paris & CATI Multicenter Neuroimaging Platform, France
| | - Samantha Galluzzi
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy
| | - Moira Marizzoni
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy
| | - Giovanni B Frisoni
- Laboratory Alzheimer's Neuroimaging & Epidemiology, IRCCS Fatebenefratelli, Brescia, Italy; Memory Clinic and LANVIE-Laboratory of Neuroimaging of Aging, University Hospitals and University of Geneva, Geneva, Switzerland.
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Liu D, Wang Z, Shu H, Zhang Z. Disrupted white matter integrity is associated with cognitive deficits in patients with amnestic mild cognitive impairment: An atlas-based study. SAGE Open Med 2016; 4:2050312116648812. [PMID: 27354916 PMCID: PMC4910535 DOI: 10.1177/2050312116648812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/31/2016] [Indexed: 11/16/2022] Open
Abstract
Objective: This study investigated white matter integrity in patients with amnestic mild cognitive impairment by diffusion tensor imaging. Methods: A total of 83 patients with amnestic mild cognitive impairment and 85 elderly healthy controls underwent neuropsychological testing and a diffusion tensor imaging scan. Whole-brain white matter data were parcellated into 50 regions based on the anatomical ICBM-DTI-81 atlas, and regional diffusion metrics consisting of fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity were calculated for each region. Diffusion tensor imaging indices were compared between groups, and it was determined that between-group differences were significantly correlated with neurocognitive performance. Results: Relative to the healthy controls group, the amnestic mild cognitive impairment group exhibited poorer cognitive performance in all neuropsychological tests except the complex figure test (p = 0.083) and showed decreased mean fractional anisotropy in the fornix, increased mean diffusivity in the fornix and bilateral uncinate fasciculus, elevated axial diffusivity in the fornix and genu of corpus callosum, and elevated radial diffusivity in the fornix and bilateral uncinate fasciculus (p < 0.05). Behaviorally, integrity of the bilateral uncinate fasciculus was correlated positively with episodic memory function, while left uncinate fasciculus integrity was positively associated with language function in the amnestic mild cognitive impairment group (p < 0.05). Conclusion: White matter abnormalities in neural pathways associated with memory were correlated with neurocognitive deficiencies in amnestic mild cognitive impairment. Given that amnestic mild cognitive impairment is putatively a prodromal syndrome for Alzheimer’s disease, this study furthers our understanding of the white matter changes associated with Alzheimer’s disease pathogenesis in the predementia stage.
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Affiliation(s)
- Duan Liu
- Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China
| | - Zan Wang
- Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China
| | - Hao Shu
- Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China
| | - Zhijun Zhang
- Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China
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29
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Macro- and micro-structural white matter differences correlate with cognitive performance in healthy aging. Brain Imaging Behav 2015; 10:168-81. [DOI: 10.1007/s11682-015-9378-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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30
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Pievani M, Paternicò D, Benussi L, Binetti G, Orlandini A, Cobelli M, Magnaldi S, Ghidoni R, Frisoni GB. Pattern of structural and functional brain abnormalities in asymptomatic granulin mutation carriers. Alzheimers Dement 2014; 10:S354-S363.e1. [PMID: 24418059 DOI: 10.1016/j.jalz.2013.09.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 08/19/2013] [Accepted: 09/05/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND To investigate the patterns of brain atrophy, white matter (WM) tract changes, and functional connectivity (FC) abnormalities in asymptomatic granulin (GRN) mutation carriers. METHODS Ten cognitively normal subjects (five mutation carriers, GRN+; years to estimated disease onset: 12±7; five mutation noncarriers, GRN-) underwent a clinical and imaging (structural, diffusion tensor, and resting-state functional magnetic resonance imaging) assessment. Brain atrophy was measured with cortical thickness analysis, WM abnormalities with tract-based spatial statistics, and FC with independent component analysis. RESULTS GRN+ showed smaller cortical thickness than GRN- in the right orbitofrontal and precentral gyrus and left rostral middle frontal gyrus. WM tracts abnormalities were limited to increased axial diffusivity in the right cingulum, superior longitudinal fasciculus, and corticospinal tract. There were no differences in FC of resting-state networks. CONCLUSION Brain atrophy and WM tract abnormalities in frontal-parietal circuits can be detected at least a decade before the estimated symptom onset in asymptomatic mutation carriers.
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Affiliation(s)
- Michela Pievani
- Laboratory of Epidemiology, Neuroimaging and Telemedicine, IRCCS Istituto Centro San Giovanni di Dio, Fatebenefratelli, Brescia, Italy
| | - Donata Paternicò
- Laboratory of Epidemiology, Neuroimaging and Telemedicine, IRCCS Istituto Centro San Giovanni di Dio, Fatebenefratelli, Brescia, Italy
| | - Luisa Benussi
- NeuroBioGen Lab-Memory Clinic, IRCCS Istituto Centro San Giovanni di Dio, Fatebenefratelli, Brescia, Italy
| | - Giuliano Binetti
- NeuroBioGen Lab-Memory Clinic, IRCCS Istituto Centro San Giovanni di Dio, Fatebenefratelli, Brescia, Italy
| | - Alberto Orlandini
- Neuroradiology and Angiology Unit, Fondazione Poliambulanza, Brescia, Italy
| | - Milena Cobelli
- Neuroradiology and Angiology Unit, Fondazione Poliambulanza, Brescia, Italy
| | - Silvia Magnaldi
- Neuroradiology and Angiology Unit, Fondazione Poliambulanza, Brescia, Italy
| | - Roberta Ghidoni
- Proteomics Unit, IRCCS Istituto Centro San Giovanni di Dio, Fatebenefratelli, Brescia, Italy
| | - Giovanni B Frisoni
- Laboratory of Epidemiology, Neuroimaging and Telemedicine, IRCCS Istituto Centro San Giovanni di Dio, Fatebenefratelli, Brescia, Italy; Memory Clinic and LANVIE - Laboratory of Neuroimaging of Aging, University Hospitals and University of Geneva, Geneva, Switzerland.
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31
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Bennett IJ, Madden DJ. Disconnected aging: cerebral white matter integrity and age-related differences in cognition. Neuroscience 2013; 276:187-205. [PMID: 24280637 DOI: 10.1016/j.neuroscience.2013.11.026] [Citation(s) in RCA: 300] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 11/08/2013] [Accepted: 11/13/2013] [Indexed: 12/13/2022]
Abstract
Cognition arises as a result of coordinated processing among distributed brain regions and disruptions to communication within these neural networks can result in cognitive dysfunction. Cortical disconnection may thus contribute to the declines in some aspects of cognitive functioning observed in healthy aging. Diffusion tensor imaging (DTI) is ideally suited for the study of cortical disconnection as it provides indices of structural integrity within interconnected neural networks. The current review summarizes results of previous DTI aging research with the aim of identifying consistent patterns of age-related differences in white matter integrity, and of relationships between measures of white matter integrity and behavioral performance as a function of adult age. We outline a number of future directions that will broaden our current understanding of these brain-behavior relationships in aging. Specifically, future research should aim to (1) investigate multiple models of age-brain-behavior relationships; (2) determine the tract-specificity versus global effect of aging on white matter integrity; (3) assess the relative contribution of normal variation in white matter integrity versus white matter lesions to age-related differences in cognition; (4) improve the definition of specific aspects of cognitive functioning related to age-related differences in white matter integrity using information processing tasks; and (5) combine multiple imaging modalities (e.g., resting-state and task-related functional magnetic resonance imaging; fMRI) with DTI to clarify the role of cerebral white matter integrity in cognitive aging.
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Affiliation(s)
- I J Bennett
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, United States
| | - D J Madden
- Brain Imaging and Analysis Center, Duke University Medical Center, United States; Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, United States.
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Serbruyns L, Gooijers J, Caeyenberghs K, Meesen RL, Cuypers K, Sisti HM, Leemans A, Swinnen SP. Bimanual motor deficits in older adults predicted by diffusion tensor imaging metrics of corpus callosum subregions. Brain Struct Funct 2013; 220:273-90. [DOI: 10.1007/s00429-013-0654-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/07/2013] [Indexed: 12/13/2022]
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Cognitive intraindividual variability and white matter integrity in aging. ScientificWorldJournal 2013; 2013:350623. [PMID: 24174913 PMCID: PMC3794509 DOI: 10.1155/2013/350623] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 07/03/2013] [Indexed: 11/25/2022] Open
Abstract
The intraindividual variability (IIV) of cognitive performance has been shown to increase with aging. While brain research has generally focused on mean performance, little is known about neural correlates of cognitive IIV. Nevertheless, some studies suggest that IIV relates more strongly than mean level of performance to the quality of white matter (WM). Our study aims to explore the relation between WM integrity and cognitive IIV by combining functional (fMRI) and structural (diffusion tensor imaging, DTI) imaging. Twelve young adults (aged 18–30 years) and thirteen older adults (61–82 years) underwent a battery of neuropsychological tasks, along with fMRI and DTI imaging. Their behavioral data were analyzed and correlated with the imaging data at WM regions of interest defined on the basis of (1) the fMRI-activated areas and (2) the Johns Hopkins University (JHU) WM tractography atlas. For both methods, fractional anisotropy, along with the mean, radial, and axial diffusivity parameters, was computed. In accord with previous studies, our results showed that the DTI parameters were more related to IIV than to mean performance. Results also indicated that age differences in the DTI parameters were more pronounced in the regions activated primarily by young adults during a choice reaction-time task than in those also activated in older adults.
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Abstract
Great effort has been dedicated to mapping the functional architecture of the brain in health and disease. The neural centers that support cognition and behavior are the "hubs" defining the salient geographic landmarks of the cerebral topography. Similar to urban cartography, however, the functionality of these hubs is critically dependent on the infrastructure permitting the transfer of relevant information from site to site, and this infrastructure is susceptible to deterioration. The groundwork of the brain lies in the form of the complexly organized myelinated nerve fibers responsible for the inter-regional transmission of electrical impulses among distinct neural areas. Damage to the myelin sheath and reduction in the total number of nerve fibers with aging are thought to result in a degradation in the efficiency of communication among neural regions and to contribute to the decline of function in older adults. This article describes selected studies that are relevant to understanding the deterioration in structural connectivity of the aging brain with a focus on potential consequences to functional network activity. First, the neural substrates of connectivity and techniques used in the study of connectivity are described with a focus on neuroimaging methodologies. This is followed with discussion of the negative effects of age on connective integrity, and the possible mechanisms and neural and cognitive consequences of this progressive disconnection. Given the potential for natural repair of certain elements of the connective network, understanding the basis of age-associated decline in connectivity could have important implications with regard to the amelioration of neural dysfunction and the restoration of the infrastructure necessary for optimal function in older adults.
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Affiliation(s)
- David H Salat
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
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Genetics of ageing-related changes in brain white matter integrity - a review. Ageing Res Rev 2013; 12:391-401. [PMID: 23128052 DOI: 10.1016/j.arr.2012.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 10/05/2012] [Accepted: 10/15/2012] [Indexed: 12/14/2022]
Abstract
White matter (WM) plays a vital role in the efficient transfer of information between grey matter regions. Modern imaging techniques such as diffusion tensor imaging (DTI) have enabled the examination of WM microstructural changes across the lifespan, but there is limited knowledge about the role genetics plays in the pattern and aetiology of age-related WM microstructural changes. Family and twin studies suggest that the heritability of WM integrity measures changes over the lifespan, with the common DTI measure, fractional anisotropy (FA), showing moderate to high heritability in adults. However, few heritability studies have been undertaken in older adults. Linkage studies in middle-aged adults suggest that specific regions on chromosomes 3 and 15 may harbour genetic variants for WM integrity. A number of studies have investigated candidate genes, with the APOE ɛ4 polymorphism being the most frequently studied. Although these candidate gene studies suggest associations of particular genes with WM integrity measures in some specific brain regions, the findings remain inconsistent due to differences in their methodologies, samples and the outcome measures used. The APOE ɛ4 allele has been associated with decreased WM integrity (FA) in the cingulum, corpus callosum and parahippocampal gyrus. Only one genome-wide association study of global WM integrity measures in older adults has been published, and reported suggestive single nucleotide polymorphisms await replication. Overall, genetic age-related WM integrity studies are lacking and a concerted effort to examine the genetic determinants of age-related decline in WM integrity is clearly needed to improve our understanding of the ageing brain.
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Fatima Z, Motosugi U, Hori M, Onodera T, Ishigame K, Yagi K, Araki T. Age-related white matter changes in high b-value q-space diffusion-weighted imaging. Neuroradiology 2012; 55:253-9. [PMID: 23053002 DOI: 10.1007/s00234-012-1099-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 09/27/2012] [Indexed: 11/30/2022]
Abstract
INTRODUCTION To assess and compare age-related diffusion changes in the white matter in different cerebral lobes, as quantified by diffusion-weighted imaging (DWI) and high b-value q-space imaging (QSI). METHODS Seventy-three cases without neurological symptoms or imaging abnormalities were grouped by age as young (<30 years, n = 20), middle-aged (30-49 years, n = 19), old (50-69 years, n = 18), and very old (> 70 years, n = 16) and imaged by a 1.5-T MR scanner for DWI and QSI. Apparent diffusion coefficient (ADC) and mean displacement (MDP) values were calculated in the white matter of frontal, parietal, and temporal lobes and compared using Dunnett's test, with the young group as a control. RESULTS MDP values in frontal and parietal lobes were significantly higher in old and very old age groups than in the young, while those in the temporal lobes were significantly higher only in the very old group. ADC values were significantly higher in all three lobes in the very old group. CONCLUSION QSI is more sensitive than DWI to age-related myelin loss in white matter.
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Affiliation(s)
- Zareen Fatima
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chūō, Yamanashi, 409-3898, Japan
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Kohama SG, Rosene DL, Sherman LS. Age-related changes in human and non-human primate white matter: from myelination disturbances to cognitive decline. AGE (DORDRECHT, NETHERLANDS) 2012; 34:1093-110. [PMID: 22203458 PMCID: PMC3448998 DOI: 10.1007/s11357-011-9357-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 12/01/2011] [Indexed: 05/04/2023]
Abstract
The cognitive decline associated with normal aging was long believed to be due primarily to decreased synaptic density and neuron loss. Recent studies in both humans and non-human primates have challenged this idea, pointing instead to disturbances in white matter (WM) including myelin damage. Here, we review both cross-sectional and longitudinal studies in humans and non-human primates that collectively support the hypothesis that WM disturbances increase with age starting at middle age in humans, that these disturbances contribute to age-related cognitive decline, and that age-related WM changes may occur as a result of free radical damage, degenerative changes in cells in the oligodendrocyte lineage, and changes in microenvironments within WM.
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Affiliation(s)
- Steven G. Kohama
- Oregon National Primate Research Center, Oregon Health and Science University, Portland, OR USA
| | | | - Larry S. Sherman
- Oregon National Primate Research Center, Oregon Health and Science University, Portland, OR USA
- Division of Neuroscience, Oregon National Primate Research Center, 505 NW 185th Ave, Beaverton, OR 97006 USA
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Haller S, Missonnier P, Herrmann FR, Rodriguez C, Deiber MP, Nguyen D, Gold G, Lovblad KO, Giannakopoulos P. Individual classification of mild cognitive impairment subtypes by support vector machine analysis of white matter DTI. AJNR Am J Neuroradiol 2012; 34:283-91. [PMID: 22976235 DOI: 10.3174/ajnr.a3223] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE MCI was recently subdivided into sd-aMCI, sd-fMCI, and md-aMCI. The current investigation aimed to discriminate between MCI subtypes by using DTI. MATERIALS AND METHODS Sixty-six prospective participants were included: 18 with sd-aMCI, 13 with sd-fMCI, and 35 with md-aMCI. Statistics included group comparisons using TBSS and individual classification using SVMs. RESULTS The group-level analysis revealed a decrease in FA in md-aMCI versus sd-aMCI in an extensive bilateral, right-dominant network, and a more pronounced reduction of FA in md-aMCI compared with sd-fMCI in right inferior fronto-occipital fasciculus and inferior longitudinal fasciculus. The comparison between sd-fMCI and sd-aMCI, as well as the analysis of the other diffusion parameters, yielded no significant group differences. The individual-level SVM analysis provided discrimination between the MCI subtypes with accuracies around 97%. The major limitation is the relatively small number of cases of MCI. CONCLUSIONS Our data show that, at the group level, the md-aMCI subgroup has the most pronounced damage in white matter integrity. Individually, SVM analysis of white matter FA provided highly accurate classification of MCI subtypes.
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Affiliation(s)
- S Haller
- Service neuro-diagnostique et neuro-interventionnel DISIM, Hôpitaux Universitaires de Genève, Rue GabriellePerret-Gentil 4, 1211 Genève 14, Switzerland.
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39
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Shepherd MN, Pomicter AD, Velazco CS, Henderson SC, Dupree JL. Paranodal reorganization results in the depletion of transverse bands in the aged central nervous system. Neurobiol Aging 2012; 33:203.e13-24. [PMID: 20888080 PMCID: PMC3282488 DOI: 10.1016/j.neurobiolaging.2010.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/26/2010] [Accepted: 08/05/2010] [Indexed: 11/16/2022]
Abstract
Paranodal axo-glial junctional complexes anchor the myelin sheath to the axon and breakdown of these complexes presumably facilitates demyelination. Myelin deterioration is also prominent in the aging central nervous system (CNS); however, the stability of the paranodal complexes in the aged CNS has not been examined. Here, we show that transverse bands, prominent components of paranodal junctions, are significantly reduced in the aged CNS; however, the number of paired clusters of both myelin and axonal paranodal proteins is not altered. Ultrastructural analyses also reveal that thicker myelin sheaths display a "piling" of paranodal loops, the cytoplasm-containing sacs that demarcate the paranode. Loops involved in piling are observed throughout the paranode and are not limited to loops positioned in either the nodal- or juxtanodal-most regions. Here, we propose that as myelination continues, previously anchored loops lose their transverse bands and recede away from the axolemma. Newly juxtaposed loops then lose their transverse bands, move laterally to fill in the gap left by the receded loops and finally reform their transverse bands. This paranodal reorganization results in conservation of paranodal length, which may be important in maintaining ion channel spacing and axonal function. Furthermore, we propose that transverse band reformation is less efficient in the aged CNS, resulting in the significant reduction of these junctional components. Although demyelination was not observed, we propose that loss of transverse bands facilitates myelin degeneration and may predispose the aged CNS to a poorer prognosis following a secondary insult.
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Affiliation(s)
- Mark N. Shepherd
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
- MD Biosciences, 2575 University Avenue W. Suite 100 St Paul, MN, USA 55114 (present address)
| | - Anthony D. Pomicter
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
| | - Cristine S. Velazco
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
| | - Scott C. Henderson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
| | - Jeffrey L. Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
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Xu J, Li Y, Lin H, Sinha R, Potenza MN. Body mass index correlates negatively with white matter integrity in the fornix and corpus callosum: a diffusion tensor imaging study. Hum Brain Mapp 2011; 34:1044-52. [PMID: 22139809 DOI: 10.1002/hbm.21491] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 09/20/2011] [Indexed: 12/17/2022] Open
Abstract
Overweight or obese body habitus is associated with cognitive deficits, impaired brain function, gray matter atrophy, and white matter (WM) hyperintensities. However, few diffusion tensor imaging (DTI) studies have assessed WM integrity in relation to overweight or obese status. This study assessed relationships between body mass index (BMI) and values of DTI parameters among 51 normal weight (lean), overweight, and obese participants who were otherwise healthy. BMI correlated negatively with fractional anisotropy and axial eigenvalues (λ(1)) in the body of corpus callosum (CC), positively with mean diffusivity and radial eigenvalues (See figure in text) in the fornix and splenium of CC, and positively with λ(1) in the right corona radiata (CR) and superior longitudinal fasciculus (SLF). These data indicate that BMI correlates negatively with WM integrity in the fornix and CC. Furthermore, the different patterns of BMI-related differences in DTI parameters at the fornix, body, and splenium of the CC, and the right CR and SLF suggest that different biological processes may underlie BMI-related impairments of WM integrity in different brain regions.
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Affiliation(s)
- Jiansong Xu
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA.
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41
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Inano S, Takao H, Hayashi N, Abe O, Ohtomo K. Effects of age and gender on white matter integrity. AJNR Am J Neuroradiol 2011; 32:2103-9. [PMID: 21998104 DOI: 10.3174/ajnr.a2785] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND AND PURPOSE DTI provides a sensitive measure of change in the microstructure of white matter integrity. The purpose of our study was to investigate age-related changes, sex differences, and age-by-sex interactions in white matter integrity (FA, AD, and RD) across the whole brain with a large sample. MATERIALS AND METHODS A total of 857 healthy subjects (mean age = 56.1 ± 9.9 years; age range = 24.9-84.8 years) were included in this study. All subjects were scanned at 3T. With use of TBSS, we examined the effects of age and sex on FA, AD, and RD in the white matter. RESULTS Global FA was negatively correlated with age (R(2) = 0.18, P < .0001), and global AD and RD were positively correlated with age (AD: R(2) = 0.02, P < .0001; RD: R(2) = 0.19, P < .0001). The correlation between age and global AD, however, was weak. Voxelwise analysis revealed a number of regions where FA was negatively correlated with age, with most of these regions showing a significant positive correlation between RD and age. There was a significant age-related FA increase in several white matter regions. Voxelwise analysis also revealed many regions where FA, AD, or RD differed between men and women; however, no region showed a significant interaction between age and sex. CONCLUSIONS Our results suggest that age-related changes in white matter integrity are more strongly associated with myelin sheath degeneration than with axonal degeneration, and that, in some specific regions, the number of remyelinated axons might increase with age. Our results also suggest that there are no sex differences in the aging process of the white matter.
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Affiliation(s)
- S Inano
- Department of Radiology, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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Jacobs HIL, Leritz EC, Williams VJ, Van Boxtel MPJ, van der Elst W, Jolles J, Verhey FRJ, McGlinchey RE, Milberg WP, Salat DH. Association between white matter microstructure, executive functions, and processing speed in older adults: the impact of vascular health. Hum Brain Mapp 2011; 34:77-95. [PMID: 21954054 DOI: 10.1002/hbm.21412] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 06/08/2011] [Accepted: 07/01/2011] [Indexed: 11/12/2022] Open
Abstract
Cerebral white matter damage is not only a commonly reported consequence of healthy aging, but is also associated with cognitive decline and dementia. The aetiology of this damage is unclear; however, individuals with hypertension have a greater burden of white matter signal abnormalities (WMSA) on MR imaging than those without hypertension. It is therefore possible that elevated blood pressure (BP) impacts white matter tissue structure which in turn has a negative impact on cognition. However, little information exists about whether vascular health indexed by BP mediates the relationship between cognition and white matter tissue structure. We used diffusion tensor imaging to examine the impact of vascular health on regional associations between white matter integrity and cognition in healthy older adults spanning the normotensive to moderate-severe hypertensive BP range (43-87 years; N = 128). We examined how white matter structure was associated with performance on tests of two cognitive domains, executive functioning (EF) and processing speed (PS), and how patterns of regional associations were modified by BP and WMSA. Multiple linear regression and structural equation models demonstrated associations between tissue structure, EF and PS in frontal, temporal, parietal, and occipital white matter regions. Radial diffusivity was more prominently associated with performance than axial diffusivity. BP only minimally influenced the relationship between white matter integrity, EF and PS. However, WMSA volume had a major impact on neurocognitive associations. This suggests that, although BP and WMSA are causally related, these differential metrics of vascular health may act via independent pathways to influence brain structure, EF and PS.
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Affiliation(s)
- Heidi I L Jacobs
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Alzheimer Center Limburg, University Maastricht, 6200 MD Maastricht, The Netherlands.
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43
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Van Impe A, Coxon JP, Goble DJ, Doumas M, Swinnen SP. White matter fractional anisotropy predicts balance performance in older adults. Neurobiol Aging 2011; 33:1900-12. [PMID: 21872363 DOI: 10.1016/j.neurobiolaging.2011.06.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 06/14/2011] [Accepted: 06/17/2011] [Indexed: 11/17/2022]
Abstract
Aging is characterized by brain structural changes that may compromise motor functions. In the context of postural control, white matter integrity is crucial for the efficient transfer of visual, proprioceptive and vestibular feedback in the brain. To determine the role of age-related white matter decline as a function of the sensory feedback necessary to correct posture, we acquired diffusion weighted images in young and old subjects. A force platform was used to measure changes in body posture under conditions of compromised proprioceptive and/or visual feedback. In the young group, no significant brain structure-balance relations were found. In the elderly however, the integrity of a cluster in the frontal forceps explained 21% of the variance in postural control when proprioceptive information was compromised. Additionally, when only the vestibular system supplied reliable information, the occipital forceps was the best predictor of balance performance (42%). Age-related white matter decline may thus be predictive of balance performance in the elderly when sensory systems start to degrade.
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Affiliation(s)
- Annouchka Van Impe
- Research Center for Movement Control and Neuroplasticity, Department of Biomedical Kinesiology, K.U. Leuven, Heverlee, Belgium
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Madden DJ, Bennett IJ, Burzynska A, Potter GG, Chen NK, Song AW. Diffusion tensor imaging of cerebral white matter integrity in cognitive aging. Biochim Biophys Acta Mol Basis Dis 2011; 1822:386-400. [PMID: 21871957 DOI: 10.1016/j.bbadis.2011.08.003] [Citation(s) in RCA: 330] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/05/2011] [Accepted: 08/08/2011] [Indexed: 12/29/2022]
Abstract
In this article we review recent research on diffusion tensor imaging (DTI) of white matter (WM) integrity and the implications for age-related differences in cognition. Neurobiological mechanisms defined from DTI analyses suggest that a primary dimension of age-related decline in WM is a decline in the structural integrity of myelin, particularly in brain regions that myelinate later developmentally. Research integrating behavioral measures with DTI indicates that WM integrity supports the communication among cortical networks, particularly those involving executive function, perceptual speed, and memory (i.e., fluid cognition). In the absence of significant disease, age shares a substantial portion of the variance associated with the relation between WM integrity and fluid cognition. Current data are consistent with one model in which age-related decline in WM integrity contributes to a decreased efficiency of communication among networks for fluid cognitive abilities. Neurocognitive disorders for which older adults are at risk, such as depression, further modulate the relation between WM and cognition, in ways that are not as yet entirely clear. Developments in DTI technology are providing a new insight into both the neurobiological mechanisms of aging WM and the potential contribution of DTI to understanding functional measures of brain activity. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.
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Affiliation(s)
- David J Madden
- Brain Imaging and Analysis Center, Duke University Medical Center, Durham, NC 27710, USA.
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45
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Engvig A, Fjell AM, Westlye LT, Moberget T, Sundseth Ø, Larsen VA, Walhovd KB. Memory training impacts short-term changes in aging white matter: a longitudinal diffusion tensor imaging study. Hum Brain Mapp 2011; 33:2390-406. [PMID: 21823209 DOI: 10.1002/hbm.21370] [Citation(s) in RCA: 189] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/17/2011] [Accepted: 05/05/2011] [Indexed: 12/19/2022] Open
Abstract
A growing body of research indicates benefits of cognitive training in older adults, but the neuronal mechanisms underlying the effect of cognitive intervention remains largely unexplored. Neuroimaging methods are sensitive to subtle changes in brain structure and show potential for enhancing our understanding of both aging- and training-related neuronal plasticity. Specifically, studies using diffusion tensor imaging (DTI) suggest substantial changes in white matter (WM) in aging, but it is not known whether cognitive training might modulate these structural alterations. We used tract-based spatial statistics (TBSS) optimized for longitudinal analysis to delineate the effects of 8 weeks intensive memory training on WM microstructure. 41 participants (mean age 61 years) matched for age, sex and education were randomly assigned to an intervention or control group. All participants underwent MRI-scanning and neuropsychological assessments at the beginning and end of the study. Longitudinal analysis across groups revealed significant increase in frontal mean diffusivity (MD), indicating that DTI is sensitive to WM structural alterations over a 10-week interval. Further, group analysis demonstrated positive effects of training on the short-term changes. Participants in the training group showed a relative increase in fractional anisotropy (FA) compared with controls. Further, a significant relationship between memory improvement and change in FA was found, suggesting a possible functional significance of the reported changes. The training effect on FA seemed to be driven by a relative decrease in radial diffusivity, which might indicate a role for myelin-related processes in WM plasticity.
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Affiliation(s)
- Andreas Engvig
- Center for the Study of Human Cognition, Department of Psychology, University of Oslo, Oslo, Norway.
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46
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Xu J, Potenza MN. White matter integrity and five-factor personality measures in healthy adults. Neuroimage 2011; 59:800-7. [PMID: 21840401 DOI: 10.1016/j.neuroimage.2011.07.040] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 07/12/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022] Open
Abstract
The five-factor model organizes personality traits into five factors: Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness. Measures of these personality traits predict people's behaviors and important outcomes of their lives. Therefore, understanding the neural correlates of these personality traits is important. This study assessed the relationships between white matter (WM) integrity and personality traits among 51 healthy participants using diffusion tensor imaging (DTI) and the revised NEO Personality Inventory (NEO-PI-R). Neuroticism correlated positively while Openness and Agreeableness correlated negatively with DTI mean diffusivity (MD) in the corona radiata and superior longitudinal fasciculus, tracts that interconnect prefrontal cortex (PFC), parietal cortex, and subcortical structures. Furthermore, Neuroticism correlated positively with MD in the anterior cingulum and uncinate fasciculus, tracts interconnecting PFC and amygdala. Openness correlated negatively with MD of WM adjacent to the dorsolateral PFC in both hemispheres. These findings suggest that greater Neuroticism associates with worse integrity of WM interconnecting extensive cortical and subcortical structures including the PFC and amygdala and that greater Openness associates with better integrity of WM interconnecting extensive cortical and subcortical structures including the dorsolateral PFC.
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Affiliation(s)
- Jiansong Xu
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA.
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47
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Multiple indices of diffusion identifies white matter damage in mild cognitive impairment and Alzheimer's disease. PLoS One 2011; 6:e21745. [PMID: 21738785 PMCID: PMC3128090 DOI: 10.1371/journal.pone.0021745] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 06/06/2011] [Indexed: 11/19/2022] Open
Abstract
The study of multiple indices of diffusion, including axial (DA), radial (DR) and mean diffusion (MD), as well as fractional anisotropy (FA), enables WM damage in Alzheimer's disease (AD) to be assessed in detail. Here, tract-based spatial statistics (TBSS) were performed on scans of 40 healthy elders, 19 non-amnestic MCI (MCIna) subjects, 14 amnestic MCI (MCIa) subjects and 9 AD patients. Significantly higher DA was found in MCIna subjects compared to healthy elders in the right posterior cingulum/precuneus. Significantly higher DA was also found in MCIa subjects compared to healthy elders in the left prefrontal cortex, particularly in the forceps minor and uncinate fasciculus. In the MCIa versus MCIna comparison, significantly higher DA was found in large areas of the left prefrontal cortex. For AD patients, the overlap of FA and DR changes and the overlap of FA and MD changes were seen in temporal, parietal and frontal lobes, as well as the corpus callosum and fornix. Analysis of differences between the AD versus MCIna, and AD versus MCIa contrasts, highlighted regions that are increasingly compromised in more severe disease stages. Microstructural damage independent of gross tissue loss was widespread in later disease stages. Our findings suggest a scheme where WM damage begins in the core memory network of the temporal lobe, cingulum and prefrontal regions, and spreads beyond these regions in later stages. DA and MD indices were most sensitive at detecting early changes in MCIa.
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48
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Goble DJ, Coxon JP, Van Impe A, Geurts M, Van Hecke W, Sunaert S, Wenderoth N, Swinnen SP. The neural basis of central proprioceptive processing in older versus younger adults: an important sensory role for right putamen. Hum Brain Mapp 2011; 33:895-908. [PMID: 21432946 DOI: 10.1002/hbm.21257] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Revised: 11/30/2010] [Accepted: 12/16/2010] [Indexed: 11/09/2022] Open
Abstract
Our sense of body position and movement independent of vision (i.e., proprioception) relies on muscle spindle feedback and is vital for performing motor acts. In this study, we first sought to elucidate age-related differences in the central processing of proprioceptive information by stimulating foot muscle spindles and by measuring neural activation with functional magnetic resonance imaging. We found that healthy older adults activated a similar, distributed network of primary somatosensory and secondary-associative cortical brain regions as young individuals during the vibration-induced muscle spindle stimulation. A significant decrease in neural activity was also found in a cluster of right putamen voxels for the older age group when compared with the younger age group. Given these differences, we performed two additional analyses within each group that quantified the degree to which age-dependent activity was related to (1) brain structure and (2) a behavioral measure of proprioceptive ability. Using diffusion tensor imaging, older (but not younger) adults with higher mean fractional anisotropy were found to have increased right putamen neural activity. Age-dependent right putamen activity seen during tendon vibration was also correlated with a behavioral test of proprioceptive ability measuring ankle joint position sense in both young and old age groups. Partial correlation tests determined that the relationship between elderly joint position sense and neural activity in right putamen was mediated by brain structure, but not vice versa. These results suggest that structural differences within the right putamen are related to reduced activation in the elderly and potentially serve as biomarker of proprioceptive sensibility in older adults.
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Affiliation(s)
- Daniel J Goble
- Motor Control Laboratory, Research Center for Movement Control and Neuroplasticity, Department of Biomedical Kinesiology, K.U. Leuven, Belgium.
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Regional specificity of MRI contrast parameter changes in normal ageing revealed by voxel-based quantification (VBQ). Neuroimage 2011; 55:1423-34. [PMID: 21277375 PMCID: PMC3093621 DOI: 10.1016/j.neuroimage.2011.01.052] [Citation(s) in RCA: 213] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 01/17/2011] [Accepted: 01/20/2011] [Indexed: 01/12/2023] Open
Abstract
Normal ageing is associated with characteristic changes in brain microstructure. Although in vivo neuroimaging captures spatial and temporal patterns of age-related changes of anatomy at the macroscopic scale, our knowledge of the underlying (patho)physiological processes at cellular and molecular levels is still limited. The aim of this study is to explore brain tissue properties in normal ageing using quantitative magnetic resonance imaging (MRI) alongside conventional morphological assessment. Using a whole-brain approach in a cohort of 26 adults, aged 18–85 years, we performed voxel-based morphometric (VBM) analysis and voxel-based quantification (VBQ) of diffusion tensor, magnetization transfer (MT), R1, and R2* relaxation parameters. We found age-related reductions in cortical and subcortical grey matter volume paralleled by changes in fractional anisotropy (FA), mean diffusivity (MD), MT and R2*. The latter were regionally specific depending on their differential sensitivity to microscopic tissue properties. VBQ of white matter revealed distinct anatomical patterns of age-related change in microstructure. Widespread and profound reduction in MT contrasted with local FA decreases paralleled by MD increases. R1 reductions and R2* increases were observed to a smaller extent in overlapping occipito-parietal white matter regions. We interpret our findings, based on current biophysical models, as a fingerprint of age-dependent brain atrophy and underlying microstructural changes in myelin, iron deposits and water. The VBQ approach we present allows for systematic unbiased exploration of the interaction between imaging parameters and extends current methods for detection of neurodegenerative processes in the brain. The demonstrated parameter-specific distribution patterns offer insights into age-related brain structure changes in vivo and provide essential baseline data for studying disease against a background of healthy ageing.
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Ryan L, Walther K, Bendlin BB, Lue LF, Walker DG, Glisky EL. Age-related differences in white matter integrity and cognitive function are related to APOE status. Neuroimage 2011; 54:1565-77. [PMID: 20804847 PMCID: PMC2997188 DOI: 10.1016/j.neuroimage.2010.08.052] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/16/2010] [Accepted: 08/19/2010] [Indexed: 11/17/2022] Open
Abstract
While an extensive literature is now available on age-related differences in white matter integrity measured by diffusion MRI, relatively little is known about the relationships between diffusion and cognitive functions in older adults. Even less is known about whether these relationships are influenced by the apolipoprotein (APOE) ε4 allele, despite growing evidence that ε4 increases cognitive impairment in older adults. The purpose of the present study was to examine these relationships in a group of community-dwelling cognitively normal older adults. Data were obtained from a sample of 126 individuals (ages 52-92) that included 32 ε4 heterozygotes, 6 ε4 homozygotes, and 88 noncarriers. Two measures of diffusion, the apparent diffusion coefficient (ADC) and fractional anisotropy (FA), were obtained from six brain regions-frontal white matter, lateral parietal white matter, the centrum semiovale, the genu and splenium of the corpus callosum, and the temporal stem white matter-and were used to predict composite scores of cognitive function in two domains, executive function and memory function. Results indicated that ADC and FA differed with increasing age in all six brain regions, and these differences were significantly greater for ε4 carriers compared to noncarriers. Importantly, after controlling for age, diffusion measures predicted cognitive function in a region-specific way that was also influenced by ε4 status. Regardless of APOE status, frontal ADC and FA independently predicted executive function scores for all participants, while temporal lobe ADC additionally predicted executive function for ε4 carriers but not noncarriers. Memory scores were predicted by temporal lobe ADC but not frontal diffusion for all participants, and this relationship was significantly stronger in ε4 carriers compared to noncarriers. Taken together, age and temporal lobe ADC accounted for a striking 53% of the variance in memory scores within the ε4 carrier group. The results provide further evidence that APOE ε4 has a significant impact on the trajectory of age-related cognitive functioning in older adults. Possible mechanisms are discussed that could account for the associations between ε4, diffusion, and cognitive function, including the influence of ε4 on neural repair, oxidative stress, and the health of myelin-producing oligodendroglia.
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Affiliation(s)
- Lee Ryan
- Evelyn F. McKnight Brain Institute, Department of Psychology, University of Arizona, Tucson, AZ 85721-0068, USA.
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