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Farmer AL, Febo M, Wilkes BJ, Lewis MH. Environmental enrichment reduces restricted repetitive behavior by altering gray matter microstructure. PLoS One 2024; 19:e0307290. [PMID: 39083450 PMCID: PMC11290697 DOI: 10.1371/journal.pone.0307290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 07/02/2024] [Indexed: 08/02/2024] Open
Abstract
Restricted, repetitive behaviors are common symptoms in neurodevelopmental disorders including autism spectrum disorder. Despite being associated with poor developmental outcomes, repetitive behaviors remain poorly understood and have limited treatment options. Environmental enrichment attenuates the development of repetitive behaviors, but the exact mechanisms remain obscure. Using the C58 mouse model of repetitive behavior, we performed diffusion tensor imaging to examine microstructural alterations associated with the development of repetitive behavior and its attenuation by environmental enrichment. The C57BL/6 mouse strain, which displays little or no repetitive behavior, was used as a control group. We observed widespread differences in diffusion metrics between C58 mice and C57BL/6 mice. In juvenile C58 mice, repetitive motor behavior displayed strong negative correlations with fractional anisotropy in multiple gray matter regions, whereas in young adult C58 mice, high repetitive motor behavior was most strongly associated with lower fractional anisotropy and higher radial diffusivity in the striatum. Environmental enrichment increased fractional anisotropy and axial diffusivity throughout gray matter regions in the brains of juvenile C58 mice and overlapped predominantly with cerebellar and sensory regions associated with repetitive behavior. Our results suggest environmental enrichment reduces repetitive behavior development by altering gray matter microstructure in the cerebellum, medial entorhinal cortex, and sensory processing regions in juvenile C58 mice. Under standard laboratory conditions, early pathology in these regions appears to contribute to later striatal and white matter dysfunction in adult C58 mice. Future studies should examine the role these regions play in the development of repetitive behavior and the relationship between sensory processing and cerebellar deficits and repetitive behavior.
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Affiliation(s)
- Anna L. Farmer
- Department of Psychology, University of Florida, Gainesville, Florida, United States of America
| | - Marcelo Febo
- Department of Psychiatry, University of Florida, Gainesville, Florida, United States of America
| | - Bradley J. Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, United States of America
| | - Mark H. Lewis
- Department of Psychology, University of Florida, Gainesville, Florida, United States of America
- Department of Psychiatry, University of Florida, Gainesville, Florida, United States of America
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Mercier O, Quilichini PP, Magalon K, Gil F, Ghestem A, Richard F, Boudier T, Cayre M, Durbec P. Transient demyelination causes long-term cognitive impairment, myelin alteration and network synchrony defects. Glia 2024; 72:960-981. [PMID: 38363046 DOI: 10.1002/glia.24513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/26/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024]
Abstract
In the adult brain, activity-dependent myelin plasticity is required for proper learning and memory consolidation. Myelin loss, alteration, or even subtle structural modifications can therefore compromise the network activity, leading to functional impairment. In multiple sclerosis, spontaneous myelin repair process is possible, but it is heterogeneous among patients, sometimes leading to functional recovery, often more visible at the motor level than at the cognitive level. In cuprizone-treated mouse model, massive brain demyelination is followed by spontaneous and robust remyelination. However, reformed myelin, although functional, may not exhibit the same morphological characteristics as developmental myelin, which can have an impact on the activity of neural networks. In this context, we used the cuprizone-treated mouse model to analyze the structural, functional, and cognitive long-term effects of transient demyelination. Our results show that an episode of demyelination induces despite remyelination long-term cognitive impairment, such as deficits in spatial working memory, social memory, cognitive flexibility, and hyperactivity. These deficits were associated with a reduction in myelin content in the medial prefrontal cortex (mPFC) and hippocampus (HPC), as well as structural myelin modifications, suggesting that the remyelination process may be imperfect in these structures. In vivo electrophysiological recordings showed that the demyelination episode altered the synchronization of HPC-mPFC activity, which is crucial for memory processes. Altogether, our data indicate that the myelin repair process following transient demyelination does not allow the complete recovery of the initial myelin properties in cortical structures. These subtle modifications alter network features, leading to prolonged cognitive deficits in mice.
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Affiliation(s)
- Océane Mercier
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Pascale P Quilichini
- U1106 after INS, Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Karine Magalon
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Florian Gil
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Antoine Ghestem
- U1106 after INS, Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Fabrice Richard
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Thomas Boudier
- Aix Marseille Univ, Turing Centre for Living Systems, Marseille, France
| | - Myriam Cayre
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Pascale Durbec
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
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Andreatta Maduro P, Guimarães MP, de Sousa Rodrigues M, Pereira Rolim Coimbra Pinto AP, da Mota Junior AA, Lima Rocha AS, Matoso JMD, Bavaresco Gambassi B, Schwingel PA. Comparing the Efficacy of Two Cognitive Screening Tools in Identifying Gray and White Matter Brain Damage among Older Adults. J Aging Res 2024; 2024:5527225. [PMID: 38690079 PMCID: PMC11060871 DOI: 10.1155/2024/5527225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/19/2024] [Accepted: 04/12/2024] [Indexed: 05/02/2024] Open
Abstract
Background Ageing is associated with structural changes in brain regions and functional decline in cognitive domains. Noninvasive tools for identifying structural damage in the brains of older adults are relevant for early treatment. Aims This study aims to evaluate and compare the accuracy of the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA©) in identifying gray and white matter brain damage in older individuals with varying degrees of cognitive impairment. Methods Ninety older adults (62 women) with an average age of 69 ± 7 years were enrolled and categorized as having no cognitive impairment (NCI), mild cognitive impairment (MCI), or moderate cognitive impairment (MoCI). Magnetic resonance imaging (MRI) was utilized to assess the number, volume, and distribution of brain damage. The Fazekas and Scheltens scales were applied to the brain MRIs, and inferential statistics were employed to compare variables among the groups. Results Cognitive impairment was observed in 56.7% of the participants (95% confidence interval (CI): 46.4-66.4%), with thirty-six older adults (40%) classified as MCI and 15 (17%) as MoCI. Cognitive impairment and medial temporal lobe (MTL) atrophy were found to be associated (p=0.001), exhibiting higher mean volume scales of the MTL atrophied area in the MoCI group (p < 0.001). The MMSE accurately revealed MTL atrophy based on the Scheltens (p < 0.05) and Fazekas (p < 0.05) scales. At the same time, the MoCA accurately identified periventricular white matter (PWM) abnormalities according to the Fazekas scale (p < 0.05). Conclusions The MMSE and MoCA screening tools effectively identified gray and white matter brain damage in older adults with varying degrees of cognitive impairment. Lower MMSE scores are associated with MTL atrophy and lesions, and lower MoCA scores are related to PWM lesions. The concurrent use of MMSE and MoCA is recommended for assessing structural changes in distinct brain regions.
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Affiliation(s)
- Paula Andreatta Maduro
- Post-Graduation Program in Health Sciences (PPGCS), University of Pernambuco (UPE), Recife, PE 50100-130, Brazil
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
- University Hospital of the Federal University of Vale do São Francisco (HU-UNIVASF), Brazilian Hospital Services Company (EBSERH), Petrolina, PE 56304-205, Brazil
| | | | - Mateus de Sousa Rodrigues
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
- University Hospital of the Federal University of Vale do São Francisco (HU-UNIVASF), Brazilian Hospital Services Company (EBSERH), Petrolina, PE 56304-205, Brazil
| | - Ana Paula Pereira Rolim Coimbra Pinto
- University Hospital of the Federal University of Vale do São Francisco (HU-UNIVASF), Brazilian Hospital Services Company (EBSERH), Petrolina, PE 56304-205, Brazil
| | - Américo Alves da Mota Junior
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
- University Hospital of the Federal University of Vale do São Francisco (HU-UNIVASF), Brazilian Hospital Services Company (EBSERH), Petrolina, PE 56304-205, Brazil
| | - Alaine Souza Lima Rocha
- Post-Graduation Program in Health Sciences (PPGCS), University of Pernambuco (UPE), Recife, PE 50100-130, Brazil
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
- Department of Physical Therapy, Federal University of Ceará (UFC), Fortaleza, CE 60430-450, Brazil
| | - Juliana Magalhães Duarte Matoso
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
- Department of Clinical Medicine, Pedro Ernesto University Hospital, State University of Rio de Janeiro (UERJ), Rio de Janeiro, RJ 20551-030, Brazil
| | - Bruno Bavaresco Gambassi
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
- Post-Graduation Program in Management of Health Programs and Services (PPGGPSS), CEUMA University (UNICEUMA), São Luís, MA 65075-120, Brazil
| | - Paulo Adriano Schwingel
- Post-Graduation Program in Health Sciences (PPGCS), University of Pernambuco (UPE), Recife, PE 50100-130, Brazil
- Human Performance Research Laboratory (LAPEDH), UPE, Petrolina, PE 56328-900, Brazil
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Kampaite A, Gustafsson R, York EN, Foley P, MacDougall NJJ, Bastin ME, Chandran S, Waldman AD, Meijboom R. Brain connectivity changes underlying depression and fatigue in relapsing-remitting multiple sclerosis: A systematic review. PLoS One 2024; 19:e0299634. [PMID: 38551913 PMCID: PMC10980255 DOI: 10.1371/journal.pone.0299634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 02/13/2024] [Indexed: 04/01/2024] Open
Abstract
Multiple Sclerosis (MS) is an autoimmune disease affecting the central nervous system, characterised by neuroinflammation and neurodegeneration. Fatigue and depression are common, debilitating, and intertwined symptoms in people with relapsing-remitting MS (pwRRMS). An increased understanding of brain changes and mechanisms underlying fatigue and depression in RRMS could lead to more effective interventions and enhancement of quality of life. To elucidate the relationship between depression and fatigue and brain connectivity in pwRRMS we conducted a systematic review. Searched databases were PubMed, Web-of-Science and Scopus. Inclusion criteria were: studied participants with RRMS (n ≥ 20; ≥ 18 years old) and differentiated between MS subtypes; published between 2001-01-01 and 2023-01-18; used fatigue and depression assessments validated for MS; included brain structural, functional magnetic resonance imaging (fMRI) or diffusion MRI (dMRI). Sixty studies met the criteria: 18 dMRI (15 fatigue, 5 depression) and 22 fMRI (20 fatigue, 5 depression) studies. The literature was heterogeneous; half of studies reported no correlation between brain connectivity measures and fatigue or depression. Positive findings showed that abnormal cortico-limbic structural and functional connectivity was associated with depression. Fatigue was linked to connectivity measures in cortico-thalamic-basal-ganglial networks. Additionally, both depression and fatigue were related to altered cingulum structural connectivity, and functional connectivity involving thalamus, cerebellum, frontal lobe, ventral tegmental area, striatum, default mode and attention networks, and supramarginal, precentral, and postcentral gyri. Qualitative analysis suggests structural and functional connectivity changes, possibly due to axonal and/or myelin loss, in the cortico-thalamic-basal-ganglial and cortico-limbic network may underlie fatigue and depression in pwRRMS, respectively, but the overall results were inconclusive, possibly explained by heterogeneity and limited number of studies. This highlights the need for further studies including advanced MRI to detect more subtle brain changes in association with depression and fatigue. Future studies using optimised imaging protocols and validated depression and fatigue measures are required to clarify the substrates underlying these symptoms in pwRRMS.
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Affiliation(s)
- Agniete Kampaite
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, Edinburgh Imaging Facility, University of Edinburgh, Edinburgh, United Kingdom
| | - Rebecka Gustafsson
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Elizabeth N. York
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, Edinburgh Imaging Facility, University of Edinburgh, Edinburgh, United Kingdom
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter Foley
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, United Kingdom
| | - Niall J. J. MacDougall
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, United Kingdom
- Department of Neurology, Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - Mark E. Bastin
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, Edinburgh Imaging Facility, University of Edinburgh, Edinburgh, United Kingdom
| | - Siddharthan Chandran
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, United Kingdom
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam D. Waldman
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, Edinburgh Imaging Facility, University of Edinburgh, Edinburgh, United Kingdom
| | - Rozanna Meijboom
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, Edinburgh Imaging Facility, University of Edinburgh, Edinburgh, United Kingdom
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Nazarova A, Drobinin V, Helmick CA, Schmidt MH, Cookey J, Uher R. Intracortical Myelin in Youths at Risk for Depression. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100285. [PMID: 38323155 PMCID: PMC10844807 DOI: 10.1016/j.bpsgos.2023.100285] [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: 09/14/2023] [Revised: 11/28/2023] [Accepted: 12/02/2023] [Indexed: 02/08/2024] Open
Abstract
Background Major depressive disorder (MDD) is a leading cause of disability. To understand why depression develops, it is important to distinguish between early neural markers of vulnerability that precede the onset of MDD and features that develop during depression. Recent neuroimaging findings suggest that reduced global and regional intracortical myelination (ICM), especially in the lateral prefrontal cortex, may be associated with depression, but it is unknown whether it is a precursor or a consequence of MDD. The study of offspring of affected parents offers the opportunity to distinguish between precursors and consequences by examining individuals who carry high risk at a time when they have not experienced depression. Methods We acquired 129 T1-weighted and T2-weighted scans from 56 (25 female) unaffected offspring of parents with depression and 114 scans from 63 (34 female) unaffected offspring of parents without a history of depression (ages 9 to 16 years). To assess scan quality, we calculated test-retest reliability. We used the scan ratios to calculate myelin maps for 68 cortical regions. We analyzed data using mixed-effects modeling. Results ICM did not differ between high and low familial risk youths in global (B = 0.06, SE = 0.03, p = .06) or regional (B = 0.05, SE = 0.03, p = .08) analyses. Our pediatric sample had high ICM reliability (intraclass correlation coefficient = 0.79; 95% CI, 0.55-0.88). Conclusions Based on our results, reduced ICM does not appear to be a precursor of MDD. Future studies should examine ICM in familial high-risk youths across a broad developmental period.
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Affiliation(s)
- Anna Nazarova
- Department of Psychiatry, Dalhousie University, Abbie J. Lane Memorial Building Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
- Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
| | - Vladislav Drobinin
- Department of Psychiatry, Dalhousie University, Abbie J. Lane Memorial Building Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
| | - Carl A. Helmick
- Department of Psychiatry, Dalhousie University, Abbie J. Lane Memorial Building Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
| | - Matthias H. Schmidt
- Department of Diagnostic Radiology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jacob Cookey
- Department of Psychiatry, Dalhousie University, Abbie J. Lane Memorial Building Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
- Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
| | - Rudolf Uher
- Department of Psychiatry, Dalhousie University, Abbie J. Lane Memorial Building Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
- Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
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6
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Farmer AL, Lewis MH. Reduction of restricted repetitive behavior by environmental enrichment: Potential neurobiological mechanisms. Neurosci Biobehav Rev 2023; 152:105291. [PMID: 37353046 DOI: 10.1016/j.neubiorev.2023.105291] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 06/04/2023] [Accepted: 06/19/2023] [Indexed: 06/25/2023]
Abstract
Restricted repetitive behaviors (RRB) are one of two diagnostic criteria for autism spectrum disorder and common in other neurodevelopmental and psychiatric disorders. The term restricted repetitive behavior refers to a wide variety of inflexible patterns of behavior including stereotypy, self-injury, restricted interests, insistence on sameness, and ritualistic and compulsive behavior. However, despite their prevalence in clinical populations, their underlying causes remain poorly understood hampering the development of effective treatments. Intriguingly, numerous animal studies have demonstrated that these behaviors are reduced by rearing in enriched environments (EE). Understanding the processes responsible for the attenuation of repetitive behaviors by EE should offer insights into potential therapeutic approaches, as well as shed light on the underlying neurobiology of repetitive behaviors. This review summarizes the current knowledge of the relationship between EE and RRB and discusses potential mechanisms for EE's attenuation of RRB based on the broader EE literature. Existing gaps in the literature and future directions are also discussed.
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Affiliation(s)
- Anna L Farmer
- Department of Psychology, University of Florida, Gainesville, FL, USA.
| | - Mark H Lewis
- Department of Psychology, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA
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7
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Valk SL, Kanske P, Park BY, Hong SJ, Böckler A, Trautwein FM, Bernhardt BC, Singer T. Functional and microstructural plasticity following social and interoceptive mental training. eLife 2023; 12:e85188. [PMID: 37417306 PMCID: PMC10414971 DOI: 10.7554/elife.85188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 07/01/2023] [Indexed: 07/08/2023] Open
Abstract
The human brain supports social cognitive functions, including Theory of Mind, empathy, and compassion, through its intrinsic hierarchical organization. However, it remains unclear how the learning and refinement of social skills shapes brain function and structure. We studied if different types of social mental training induce changes in cortical function and microstructure, investigating 332 healthy adults (197 women, 20-55 years) with repeated multimodal neuroimaging and behavioral testing. Our neuroimaging approach examined longitudinal changes in cortical functional gradients and myelin-sensitive T1 relaxometry, two complementary measures of cortical hierarchical organization. We observed marked changes in intrinsic cortical function and microstructure, which varied as a function of social training content. In particular, cortical function and microstructure changed as a result of attention-mindfulness and socio-cognitive training in regions functionally associated with attention and interoception, including insular and parietal cortices. Conversely, socio-affective and socio-cognitive training resulted in differential microstructural changes in regions classically implicated in interoceptive and emotional processing, including insular and orbitofrontal areas, but did not result in functional reorganization. Notably, longitudinal changes in cortical function and microstructure predicted behavioral change in attention, compassion and perspective-taking. Our work demonstrates functional and microstructural plasticity after the training of social-interoceptive functions, and illustrates the bidirectional relationship between brain organisation and human social skills.
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Affiliation(s)
- Sofie Louise Valk
- Otto Hahn Group Cognitive Neurogenetics, Max Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
- INM-7, FZ JülichJülichGermany
| | - Philipp Kanske
- Clinical Psychology and Behavioral Neuroscience, Faculty of Psychology, Technische Universität DresdenDresdenGermany
- Max Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
| | - Bo-yong Park
- Multimodal Imaging and Connectome Analysis Lab, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill UniversityMontrealCanada
- Department of Data Science, Inha UniversityIncheonRepublic of Korea
- Center for Neuroscience Imaging Research, Institute for Basic ScienceSuwonRepublic of Korea
| | - Seok-Jun Hong
- Center for Neuroscience Imaging Research, Institute for Basic ScienceSuwonRepublic of Korea
- Center for the Developing Brain, Child Mind InstituteNew YorkUnited States
- Department of Biomedical Engineering, Sungkyunkwan UniversitySuwonRepublic of Korea
| | - Anne Böckler
- Department of Psychology, Wurzburg UniversityWurzburgGermany
| | - Fynn-Mathis Trautwein
- Department of Psychosomatic Medicine and Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine, University of FreiburgFreiburgGermany
| | - Boris C Bernhardt
- Multimodal Imaging and Connectome Analysis Lab, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill UniversityMontrealCanada
| | - Tania Singer
- Social Neuroscience Lab, Max Planck SocietyBerlinGermany
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Vinogradova A, Sysova M, Smirnova P, Sidorova M, Turkin A, Kurilova E, Tuchina O. Enriched Environment Induces Sex-Specific Changes in the Adult Neurogenesis, Cytokine and miRNA Expression in Rat Hippocampus. Biomedicines 2023; 11:biomedicines11051341. [PMID: 37239012 DOI: 10.3390/biomedicines11051341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/28/2023] [Accepted: 04/30/2023] [Indexed: 05/28/2023] Open
Abstract
An enriched environment stimulates adult hippocampal plasticity, but the exact cellular and molecular mechanisms are complex, and thus a matter of debate. We studied the behavior and hippocampal neurogenesis in adult male and female Wistar rats that were housed in an enriched environment (EE) for two months. Both EE males and females performed better than control animals in a Barnes maze, meaning that EE enhances spatial memory. However, the expression levels of neurogenesis markers KI67, DCX, Nestin, and Syn1 increased only in EE females, while in EE males only KI67 and BDNF were higher than in the corresponding control. The number of DCX+ neurons on brain slices increased in the dentate gyrus of EE females only, i.e., the level of adult hippocampal neurogenesis was increased in female but not in male rats. The level of anti-inflammatory IL-10 and signaling pathway components was upregulated in EE females. Of 84 miRNAs tested, in the hippocampi of EE female rats we detected upregulation in the expression levels of 12 miRNAs related to neuronal differentiation and morphogenesis, while in EE males four miRNAs were upregulated and involved in the regulation of cell proliferation/differentiation, and one was downregulated and associated with the stimulation of proliferation. Taken altogether, our results point to sex-specific differences in adult hippocampal plasticity, IL-10 expression, and miRNA profiles induced by an enriched environment.
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Affiliation(s)
- Anna Vinogradova
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
| | - Maria Sysova
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
| | - Polina Smirnova
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
| | - Maria Sidorova
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
| | - Andrei Turkin
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
| | - Ekaterina Kurilova
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
| | - Oksana Tuchina
- Educational and Scientific Cluster "Institute of Medicine and Life Sciences (MEDBIO)", Immanuel Kant Baltic Federal University, 14 A. Nevskogo str., 236016 Kaliningrad, Russia
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9
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Sánchez SM, Schmidt H, Gallardo G, Anwander A, Brauer J, Friederici AD, Knösche TR. White matter brain structure predicts language performance and learning success. Hum Brain Mapp 2023; 44:1445-1455. [PMID: 36399515 PMCID: PMC9921223 DOI: 10.1002/hbm.26132] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 09/01/2022] [Accepted: 10/11/2022] [Indexed: 11/19/2022] Open
Abstract
Individual differences in the ability to process language have long been discussed. Much of the neural basis of these, however, is yet unknown. Here we investigated the relationship between long-range white matter connectivity of the brain, as revealed by diffusion tractography, and the ability to process syntactically complex sentences in the participants' native language as well as the improvement thereof by multiday training. We identified specific network motifs by singular value decomposition that indeed related white matter structural connectivity to individual language processing performance. First, for two such motifs, one in the left and one in the right hemisphere, their individual prevalence significantly predicted the individual language performance, suggesting an anatomical predisposition for the individual ability to process syntactically complex sentences. Both motifs comprise a number of cortical regions, but seem to be dominated by areas known for the involvement in working memory rather than the classical language network itself. Second, we identified another left hemispheric network motif, whose change of prevalence over the training period significantly correlated with the individual change in performance, thus reflecting training induced white matter plasticity. This motif comprises diverse cortical areas including regions known for their involvement in language processing, working memory and motor functions. The present findings suggest that individual differences in language processing and learning can be explained, in part, by individual differences in the brain's white matter structure. Brain structure may be a crucial factor to be considered when discussing variations in human cognitive performance, more generally.
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Affiliation(s)
- Stella M Sánchez
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Max Planck Institute for Human Cognitive and Brain Sciences, Brain Networks Group, Leipzig, Germany.,Laureate Institute for Brain Research, Tulsa, Oklahoma, USA
| | - Helmut Schmidt
- Max Planck Institute for Human Cognitive and Brain Sciences, Brain Networks Group, Leipzig, Germany.,Institute of Computer Science, Czech Academy of Sciences, Prague, Czech Republic
| | - Guillermo Gallardo
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Alfred Anwander
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Jens Brauer
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Friedrich Schiller University, Office of the Vice-President for Young Researchers, Jena, Germany
| | - Angela D Friederici
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Thomas R Knösche
- Max Planck Institute for Human Cognitive and Brain Sciences, Brain Networks Group, Leipzig, Germany.,Institute of Biomedical Engineering and Informatics, TU Ilmenau, Ilmenau, Germany
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Feng J, Men W, Yu X, Liu W, Zhang S, Liu J, Ma L. High-altitude exposure duration dependent global and regional gray matter volume decrease in healthy immigrants: a cross-sectional study. Acta Radiol 2023; 64:751-759. [PMID: 35369766 DOI: 10.1177/02841851221091674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The correlation between brain injury and high-altitude (HA) exposure duration (Dur_HA) as well as peripheral oxygen saturation (SpO2) remains unclear. PURPOSE To evaluate the global and regional brain volume differences between HA immigrants and sea-level residents, and the relationship between brain volume with Dur_HA and SpO2. MATERIAL AND METHODS Structural magnetic resonance imaging (MRI) scans were acquired in 33 healthy male HA immigrants (HA group) and 33 matched sea-level male residents (SL group). Differences in global gray matter volume (GMV), white matter volume (WMV), brain parenchyma volume (BV), total intracranial volume (TIV), and the volume-fraction (the ratio of GMV/TIV, WMV/TIV, BV/TIV) were assessed. Regional gray matter differences were investigated using voxel-based morphology analysis. The volume of clusters with GM loss were calculated as the volume of volume of interest (V_VOI). Student's t-test and partial correlation were adopted for statistic calculation. RESULTS Compared to the SL group, the HA immigrants had larger WMV (P = 0.015), smaller ratio of GMV/WMV (P = 0.022), and regional gray matter loss in bilateral basal ganglion, limbic system, midbrain, and vermis (cluster size >100 voxels, family-wise error corrected at P = 0.01). The global GMV, BV, and V_VOI confined to vermis had negative correlations with the Dur_HA (r = -0.369, P = 0.049; r = -0.380, P = 0.042; and r = -0.471, P = 0.010. Neither global nor regional brain volume correlated with SpO2. CONCLUSION Global and regional brain are affected by long-term HA exposure, and global and regional gray matter have a time-dependent volume loss.
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Affiliation(s)
- Jie Feng
- 104607Medical School of Chinese People's Liberation Army, Beijing, PR China
- Department of Radiology, The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, PR China
- Department of Radiology, Corps Hospital of Shanxi Province of Chinese People's Armed Police Force, Taiyuan, PR China
| | - Weiwei Men
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, PR China
- Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, PR China
| | - Xiao Yu
- 104607Medical School of Chinese People's Liberation Army, Beijing, PR China
- Department of Radiology, The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, PR China
| | - Wenjia Liu
- Department of Radiology, The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, PR China
| | - Shiyu Zhang
- 104607Medical School of Chinese People's Liberation Army, Beijing, PR China
- Department of Radiology, Beijing Friendship Hospital, 535066Capital Medical University, Beijing, PR China
| | - Jie Liu
- Department of Radiology, General Hospital of Tibet Military Region, Lhasa, Tibet, PR China
| | - Lin Ma
- 104607Medical School of Chinese People's Liberation Army, Beijing, PR China
- Department of Radiology, The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, PR China
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11
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Rasia-Filho AA, Calcagnotto ME, von Bohlen Und Halbach O. Glial Cell Modulation of Dendritic Spine Structure and Synaptic Function. ADVANCES IN NEUROBIOLOGY 2023; 34:255-310. [PMID: 37962798 DOI: 10.1007/978-3-031-36159-3_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Glia comprise a heterogeneous group of cells involved in the structure and function of the central and peripheral nervous system. Glial cells are found from invertebrates to humans with morphological specializations related to the neural circuits in which they are embedded. Glial cells modulate neuronal functions, brain wiring and myelination, and information processing. For example, astrocytes send processes to the synaptic cleft, actively participate in the metabolism of neurotransmitters, and release gliotransmitters, whose multiple effects depend on the targeting cells. Human astrocytes are larger and more complex than their mice and rats counterparts. Astrocytes and microglia participate in the development and plasticity of neural circuits by modulating dendritic spines. Spines enhance neuronal connectivity, integrate most postsynaptic excitatory potentials, and balance the strength of each input. Not all central synapses are engulfed by astrocytic processes. When that relationship occurs, a different pattern for thin and large spines reflects an activity-dependent remodeling of motile astrocytic processes around presynaptic and postsynaptic elements. Microglia are equally relevant for synaptic processing, and both glial cells modulate the switch of neuroendocrine secretion and behavioral display needed for reproduction. In this chapter, we provide an overview of the structure, function, and plasticity of glial cells and relate them to synaptic maturation and modulation, also involving neurotrophic factors. Together, neurons and glia coordinate synaptic transmission in both normal and abnormal conditions. Neglected over decades, this exciting research field can unravel the complexity of species-specific neural cytoarchitecture as well as the dynamic region-specific functional interactions between diverse neurons and glial subtypes.
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Affiliation(s)
- Alberto A Rasia-Filho
- Department of Basic Sciences/Physiology and Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Maria Elisa Calcagnotto
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Psychiatry and Behavioral Science, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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12
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Normal Cortical Myelination in Galectin-4-Deficient Mice. Cells 2022; 11:cells11213485. [DOI: 10.3390/cells11213485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Myelin, critical for the correct function of the nervous system, is organized in different patterns that can include long non-myelinated axonal segments. How myelin patterning is regulated remains unexplained. The carbohydrate-binding protein galectin-4 (Gal-4) influences oligodendrocyte differentiation in vitro and is associated with non-myelinable axon segments (NMS) in cultured neurons. In consequence, Gal-4 has been proposed as a myelin patterning regulator, although no in vivo studies have corroborated this hypothesis. We used Gal-4-deficient mice (Lgals4-KO) to study the role of Gal-4 in cortical myelination in vivo. We show that cultured neurons of Lgals4-KO mice form NMS that are regulated as in control neurons. In addition, oligodendrocyte/myelin markers expression measured by biochemical and immunochemical means, and cortical myelin microstructure studied by in-depth image analysis appear unaltered in these animals. Consistently, myelin displays an essentially normal function assessed by in vivo electrophysiology and locomotion analyses. In conclusion, cortical myelin of Lgals4-KO mice does not show any significant defect in composition, organization or function, pointing to a negligible role of Gal-4 in myelination in vivo or, as discussed, to unknown mechanisms that compensate its absence.
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13
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Mackes NK, Mehta MA, Beyh A, Nkrumah RO, Golm D, Sarkar S, Fairchild G, Dell'Acqua F, Sonuga-Barke EJS. A Prospective Study of the Impact of Severe Childhood Deprivation on Brain White Matter in Adult Adoptees: Widespread Localized Reductions in Volume But Unaffected Microstructural Organization. eNeuro 2022; 9:ENEURO.0188-22.2022. [PMID: 36376082 PMCID: PMC9665880 DOI: 10.1523/eneuro.0188-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 11/16/2022] Open
Abstract
Early childhood neglect can impact brain development across the lifespan. Using voxel-based approaches we recently reported that severe and time-limited institutional deprivation in early childhood was linked to substantial reductions in total brain volume in adulthood, >20 years later. Here, we extend this analysis to explore deprivation-related regional white matter volume and microstructural organization using diffusion-based techniques. A combination of tensor-based morphometry (TBM) analysis and tractography was conducted on diffusion-weighted imaging (DWI) data from 59 young adults who spent between 3 and 41 months in the severely depriving Romanian institutions of the 1980s before being adopted into United Kingdom families, and 20 nondeprived age-matched United Kingdom controls. Independent of total volume, institutional deprivation was associated with smaller volumes in localized regions across a range of white matter tracts including (1) long-ranging association fibers such as bilateral inferior longitudinal fasciculus (ILF), bilateral inferior fronto-occipital fasciculus (IFOF), left superior longitudinal fasciculi (SLFs), and left arcuate fasciculus; (2) tracts of the limbic circuitry including fornix and cingulum; and (3) projection fibers with the corticospinal tract particularly affected. Tractographic analysis found no evidence of altered microstructural organization of any tract in terms of hindrance modulated orientational anisotropy (HMOA), fractional anisotropy (FA), or mean diffusivity (MD). We provide further evidence for the effects of early neglect on brain development and their persistence in adulthood despite many years of environmental enrichment associated with successful adoption. Localized white matter effects appear limited to volumetric changes with microstructural organization unaffected.
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Affiliation(s)
- Nuria K Mackes
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 8AF, United Kingdom
| | - Mitul A Mehta
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 8AF, United Kingdom
| | - Ahmad Beyh
- Department of Forensic & Neurodevelopmental Sciences. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 8AF, United Kingdom
| | - Richard O Nkrumah
- Department of Neuroimaging, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim J5 68159, Germany
| | - Dennis Golm
- Centre for Innovation in Mental Health, School of Psychology, University of Southampton, Southampton SO17 1PS, United Kingdom
| | - Sagari Sarkar
- Cognitive Neuroscience & Neuropsychiatry, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Graeme Fairchild
- Department of Psychology, University of Bath, Bath BA2 7AY, United Kingdom
| | - Flavio Dell'Acqua
- Department of Forensic & Neurodevelopmental Sciences. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 8AF, United Kingdom
| | - Edmund J S Sonuga-Barke
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 8AF, United Kingdom
- Department of Child & Adolescent Psychiatry, Aarhus University, Aarhus 8000, Denmark
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14
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Diez A, Wang S, Carfagnini N, MacDougall-Shackleton SA. Sex differences in myelination of the zebra finch vocal control system emerge relatively late in development. Dev Neurobiol 2022; 82:581-595. [PMID: 36207011 DOI: 10.1002/dneu.22900] [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: 01/13/2022] [Revised: 08/30/2022] [Accepted: 09/21/2022] [Indexed: 01/30/2023]
Abstract
The role of myelination in the development of motor control is widely known, but its role in the development of cognitive abilities is less understood. Here, we examined sex differences in the development of myelination of structures and tracts that support song learning and production in songbirds. We collected brains from 63 young male and female zebra finches (Taeniopygia guttata) over four stages of development that correspond to different stages of song learning. Using a myelination marker (myelin basic protein), we measured the development of myelination in three different nuclei of the vocal control system (HVC, RA, and lateral magnocellular nucleus of the anterior nidopallium [LMAN]) and two tracts (HVC-RA and lamina mesopallium ventralis [LMV]). We found that the myelination of the vocal control nuclei and tracts is sex related and male biased. In males, the patterns of myelination were age-dependent, asynchronous in rate and progression and associated with the development of song learning and production. In females, myelination of vocal control nuclei was low or absent and did not significantly change with age. Sex differences in myelination of the HVC-RA tract were large and emerged late in development well after sex differences in the size of vocal control brain regions are established. Myelination of this tract in males coincides with the age of song crystallization. Overall, the changes in myelination in the vocal control areas and tracts measured are region-, age-, and sex-specific and are consistent with sex differences in song development.
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Affiliation(s)
- Adriana Diez
- Graduate Program in Neuroscience, University of Western Ontario, London, Canada.,Advanced Facility for Avian Research, University of Western Ontario, London, Canada
| | - Shenghan Wang
- Department of Psychology, University of Western Ontario, London, Canada
| | - Nicole Carfagnini
- Department of Biology, University of Western Ontario, London, Canada
| | - Scott A MacDougall-Shackleton
- Graduate Program in Neuroscience, University of Western Ontario, London, Canada.,Advanced Facility for Avian Research, University of Western Ontario, London, Canada.,Department of Psychology, University of Western Ontario, London, Canada.,Department of Biology, University of Western Ontario, London, Canada
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15
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Wolpaw JR, Kamesar A. Heksor: The CNS substrate of an adaptive behavior. J Physiol 2022; 600:3423-3452. [PMID: 35771667 PMCID: PMC9545119 DOI: 10.1113/jp283291] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
Over the past half‐century, the largely hardwired central nervous system (CNS) of 1970 has become the ubiquitously plastic CNS of today, in which change is the rule not the exception. This transformation complicates a central question in neuroscience: how are adaptive behaviours – behaviours that serve the needs of the individual – acquired and maintained through life? It poses a more basic question: how do many adaptive behaviours share the ubiquitously plastic CNS? This question compels neuroscience to adopt a new paradigm. The core of this paradigm is a CNS entity with unique properties, here given the name heksor from the Greek hexis. A heksor is a distributed network of neurons and synapses that changes itself as needed to maintain the key features of an adaptive behaviour, the features that make the behaviour satisfactory. Through their concurrent changes, the numerous heksors that share the CNS negotiate the properties of the neurons and synapses that they all use. Heksors keep the CNS in a state of negotiated equilibrium that enables each heksor to maintain the key features of its behaviour. The new paradigm based on heksors and the negotiated equilibrium they create is supported by animal and human studies of interactions among new and old adaptive behaviours, explains otherwise inexplicable results, and underlies promising new approaches to restoring behaviours impaired by injury or disease. Furthermore, the paradigm offers new and potentially important answers to extant questions, such as the generation and function of spontaneous neuronal activity, the aetiology of muscle synergies, and the control of homeostatic plasticity.
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Affiliation(s)
- Jonathan R Wolpaw
- Director, National Center for Adaptive Neurotechnologies, Professor of Biomedical Sciences, State University of New York at Albany, Albany Stratton VA Medical Center, Albany, NY, 12208
| | - Adam Kamesar
- Professor of Judaeo-Hellenistic Literature, Hebrew Union College, Cincinnati, Ohio, 45220
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16
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Bonetto G, Belin D, Káradóttir RT. Myelin: A gatekeeper of activity-dependent circuit plasticity? Science 2021; 374:eaba6905. [PMID: 34618550 DOI: 10.1126/science.aba6905] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Giulia Bonetto
- Wellcome-Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - David Belin
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - Ragnhildur Thóra Káradóttir
- Wellcome-Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.,Department of Physiology, Biomedical Centre, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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17
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Periods of synchronized myelin changes shape brain function and plasticity. Nat Neurosci 2021; 24:1508-1521. [PMID: 34711959 DOI: 10.1038/s41593-021-00917-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 07/30/2021] [Indexed: 12/11/2022]
Abstract
Myelin, a lipid membrane that wraps axons, enabling fast neurotransmission and metabolic support to axons, is conventionally thought of as a static structure that is set early in development. However, recent evidence indicates that in the central nervous system (CNS), myelination is a protracted and plastic process, ongoing throughout adulthood. Importantly, myelin is emerging as a potential modulator of neuronal networks, and evidence from human studies has highlighted myelin as a major player in shaping human behavior and learning. Here we review how myelin changes throughout life and with learning. We discuss potential mechanisms of myelination at different life stages, explore whether myelin plasticity provides the regenerative potential of the CNS white matter, and question whether changes in myelin may underlie neurological disorders.
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18
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Chorghay Z, MacFarquhar D, Li VJ, Aufmkolk S, Schohl A, Wiseman PW, Káradóttir RT, Ruthazer ES. Activity-dependent alteration of early myelin ensheathment in a developing sensory circuit. J Comp Neurol 2021; 530:871-885. [PMID: 34599848 DOI: 10.1002/cne.25253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 12/23/2022]
Abstract
Myelination allows for the regulation of conduction velocity, affecting the precise timing of neuronal inputs important for the development and function of brain circuits. In turn, myelination may be altered by changes in experience, neuronal activity, and vesicular release, but the links between sensory experience, corresponding neuronal activity, and resulting alterations in myelination require further investigation. We thus studied the development of myelination in the Xenopus laevis tadpole, a classic model for studies of visual system development and function because it is translucent and visually responsive throughout the formation of its retinotectal system. We begin with a systematic characterization of the timecourse of early myelin ensheathment in the Xenopus retinotectal system using immunohistochemistry of myelin basic protein (MBP) along with third harmonic generation (THG) microscopy, a label-free structural imaging technique. Based on the mid-larval developmental progression of MBP expression in Xenopus, we identified an appropriate developmental window in which to assess the effects of early temporally patterned visual experience on myelin ensheathment. We used calcium imaging of axon terminals in vivo to characterize the responses of retinal ganglion cells over a range of stroboscopic stimulation frequencies. Strobe frequencies that reliably elicited robust versus dampened calcium responses were then presented to animals for 7 d, and differences in the amount of early myelin ensheathment at the optic chiasm were subsequently quantified. This study provides evidence that it is not just the presence but also to the specific temporal properties of sensory stimuli that are important for myelin plasticity.
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Affiliation(s)
- Zahraa Chorghay
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - David MacFarquhar
- Department of Chemistry, Otto Maass Building, McGill University, Montréal, QC, Canada.,Department of Physics, Otto Maass Building, McGill University, Montréal, QC, Canada
| | - Vanessa J Li
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Sarah Aufmkolk
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.,Department of Chemistry, Otto Maass Building, McGill University, Montréal, QC, Canada.,Department of Physics, Otto Maass Building, McGill University, Montréal, QC, Canada
| | - Anne Schohl
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Paul W Wiseman
- Department of Chemistry, Otto Maass Building, McGill University, Montréal, QC, Canada.,Department of Physics, Otto Maass Building, McGill University, Montréal, QC, Canada
| | - Ragnhildur Thóra Káradóttir
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.,Department of Physiology, BioMedical Center, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Edward S Ruthazer
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
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19
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Dong W, Miao H, Li H, Wu F. Electroacupuncture Inhibits Myelin Sheath Injury in the Internal Capsule After Focal Cerebral Infarction in Rats Through the Nogo-A/NgR Signaling Pathway. Med Sci Monit Basic Res 2021; 27:e933253. [PMID: 34593748 PMCID: PMC8491559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023] Open
Abstract
BACKGROUND Ischemic stroke is usually accompanied by white matter damage. The effect of electroacupuncture (EA) on ameliorating white matter damage is still unclear. The purpose of this study was to explore the precise mechanism of EA in treating ischemic white matter. MATERIAL AND METHODS In this study, 40 Sprague-Dawley rats were randomly divided into 4 groups: normal group, the sham-operated group, model group, and EA group. The stroke model was established by right middle cerebral artery occlusion, and EA was performed 24 h after the operation for 30 min per day. After 14 days of treatment, brain tissue samples were collected. Hematoxylin and eosin and Luxol fast blue staining were used to observe the changes of white matter damage in the internal capsule (IC). The expression levels of myelin basic protein (MBP), Nogo-A, and Nogo-A receptor (NgR) were detected by immunohistochemistry and western blot. RESULTS Compared with the sham-operated group, the model group had decreased expression of MBP and significantly increased expression of Nogo-A and NgR (P<0.05). Compared with the model group, the IC damage was alleviated in the EA group. Immunohistochemistry and western blot analysis showed that EA significantly increased the expression of MBP in white matter (P<0.05) and downregulated the expression levels of Nogo-A and NgR (P<0.05). CONCLUSIONS The results of this study indicate that EA can inhibit the expression of Nogo-A/NgR and promote myelin sheath regeneration.
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20
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Maguire AS, Martin DR. White Matter Pathology as a Barrier to Gangliosidosis Gene Therapy. Front Cell Neurosci 2021; 15:682106. [PMID: 34456684 PMCID: PMC8397537 DOI: 10.3389/fncel.2021.682106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/23/2021] [Indexed: 11/25/2022] Open
Abstract
The gangliosidoses are a family of neurodegenerative lysosomal storage diseases that have recently seen promising advances in gene therapy. White matter deficits are well established components of gangliosidosis pathology that are now receiving more attention because they are partially refractory to correction by gene therapy. After a brief synopsis of normal myelinogenesis, this review outlines current viewpoints on the origin of white matter deficits in the gangliosidoses and potential obstacles to treating them effectively by gene therapy. Dysmyelinogenesis (failure of myelin sheaths to form properly) is proposed as the predominant contributor to white matter pathology, but precise mechanistic details are not well understood. The involvement of neuronal storage deficits may extend beyond secondary demyelination (destruction of myelin due to axonal loss) and contribute to dysmyelinogenesis. Preclinical studies in animal models of the gangliosidoses have substantially improved lifespan and quality of life, leading to the initiation of several clinical trials. However, improvement of white matter pathology has lagged behind other metrics and few evidence-based explanations have been proposed to date. Research groups in the field are encouraged to include myelin-specific investigations in future gene therapy work to address this gap in knowledge.
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Affiliation(s)
- Anne S. Maguire
- Scott-Ritchey Research Center, Auburn University College of Veterinary Medicine, Auburn, AL, United States
- Department of Anatomy, Physiology, and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL, United States
| | - Douglas R. Martin
- Scott-Ritchey Research Center, Auburn University College of Veterinary Medicine, Auburn, AL, United States
- Department of Anatomy, Physiology, and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL, United States
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21
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Purkinje cell axonal swellings enhance action potential fidelity and cerebellar function. Nat Commun 2021; 12:4129. [PMID: 34226561 PMCID: PMC8257784 DOI: 10.1038/s41467-021-24390-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/11/2021] [Indexed: 11/08/2022] Open
Abstract
Axonal plasticity allows neurons to control their output, which critically determines the flow of information in the brain. Axon diameter can be regulated by activity, yet how morphological changes in an axon impact its function remains poorly understood. Axonal swellings have been found on Purkinje cell axons in the cerebellum both in healthy development and in neurodegenerative diseases, and computational models predicts that axonal swellings impair axonal function. Here we report that in young Purkinje cells, axons with swellings propagated action potentials with higher fidelity than those without, and that axonal swellings form when axonal failures are high. Furthermore, we observed that healthy young adult mice with more axonal swellings learn better on cerebellar-related tasks than mice with fewer swellings. Our findings suggest that axonal swellings underlie a form of axonal plasticity that optimizes the fidelity of action potential propagation in axons, resulting in enhanced learning.
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22
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Mendez Colmenares A, Voss MW, Fanning J, Salerno EA, Gothe NP, Thomas ML, McAuley E, Kramer AF, Burzynska AZ. White matter plasticity in healthy older adults: The effects of aerobic exercise. Neuroimage 2021; 239:118305. [PMID: 34174392 DOI: 10.1016/j.neuroimage.2021.118305] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/15/2022] Open
Abstract
White matter deterioration is associated with cognitive impairment in healthy aging and Alzheimer's disease. It is critical to identify interventions that can slow down white matter deterioration. So far, clinical trials have failed to demonstrate the benefits of aerobic exercise on the adult white matter using diffusion Magnetic Resonance Imaging. Here, we report the effects of a 6-month aerobic walking and dance interventions (clinical trial NCT01472744) on white matter integrity in healthy older adults (n = 180, 60-79 years) measured by changes in the ratio of calibrated T1- to T2-weighted images (T1w/T2w). Specifically, the aerobic walking and social dance interventions resulted in positive changes in the T1w/T2w signal in late-myelinating regions, as compared to widespread decreases in the T1w/T2w signal in the active control. Notably, in the aerobic walking group, positive change in the T1w/T2w signal correlated with improved episodic memory performance. Lastly, intervention-induced increases in cardiorespiratory fitness did not correlate with change in the T1w/T2w signal. Together, our findings suggest that white matter regions that are vulnerable to aging retain some degree of plasticity that can be induced by aerobic exercise training. In addition, we provided evidence that the T1w/T2w signal may be a useful and broadly accessible measure for studying short-term within-person plasticity and deterioration in the adult human white matter.
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Affiliation(s)
- Andrea Mendez Colmenares
- Department of Human Development and Family Studies/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, 80523, United States; Department of Psychology/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, 80523, United States
| | - Michelle W Voss
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, 52242, United States
| | - Jason Fanning
- Department of Health and Exercise Sciences, Wake Forest University, Winston-Salem, NC, 27109, United States
| | - Elizabeth A Salerno
- Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO, 63130, United States
| | - Neha P Gothe
- Department of Kinesiology and Community Health, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Michael L Thomas
- Department of Psychology/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, 80523, United States
| | - Edward McAuley
- Department of Kinesiology and Community Health, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Arthur F Kramer
- Department of Kinesiology and Community Health, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States; Department of Psychology, Northeastern University, Boston, MA, 02115, United States
| | - Agnieszka Z Burzynska
- Department of Psychology, Northeastern University, Boston, MA, 02115, United States.
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23
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Tremblay SA, Jäger AT, Huck J, Giacosa C, Beram S, Schneider U, Grahl S, Villringer A, Tardif CL, Bazin PL, Steele CJ, Gauthier CJ. White matter microstructural changes in short-term learning of a continuous visuomotor sequence. Brain Struct Funct 2021; 226:1677-1698. [PMID: 33885965 DOI: 10.1007/s00429-021-02267-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 03/26/2021] [Indexed: 11/29/2022]
Abstract
Efficient neural transmission is crucial for optimal brain function, yet the plastic potential of white matter (WM) has long been overlooked. Growing evidence now shows that modifications to axons and myelin occur not only as a result of long-term learning, but also after short training periods. Motor sequence learning (MSL), a common paradigm used to study neuroplasticity, occurs in overlapping learning stages and different neural circuits are involved in each stage. However, most studies investigating short-term WM plasticity have used a pre-post design, in which the temporal dynamics of changes across learning stages cannot be assessed. In this study, we used multiple magnetic resonance imaging (MRI) scans at 7 T to investigate changes in WM in a group learning a complex visuomotor sequence (LRN) and in a control group (SMP) performing a simple sequence, for five consecutive days. Consistent with behavioral results, where most improvements occurred between the two first days, structural changes in WM were observed only in the early phase of learning (d1-d2), and in overall learning (d1-d5). In LRNs, WM microstructure was altered in the tracts underlying the primary motor and sensorimotor cortices. Moreover, our structural findings in WM were related to changes in functional connectivity, assessed with resting-state functional MRI data in the same cohort, through analyses in regions of interest (ROIs). Significant changes in WM microstructure were found in a ROI underlying the right supplementary motor area. Together, our findings provide evidence for highly dynamic WM plasticity in the sensorimotor network during short-term MSL.
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Affiliation(s)
- Stéfanie A Tremblay
- Department of Physics/PERFORM Center, Concordia University, Montreal, QC, Canada.,Montreal Heart Institute, Montreal, QC, Canada
| | - Anna-Thekla Jäger
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Charite Universitätsmedizin, Charite, Berlin, Germany
| | - Julia Huck
- Department of Physics/PERFORM Center, Concordia University, Montreal, QC, Canada
| | - Chiara Giacosa
- Department of Physics/PERFORM Center, Concordia University, Montreal, QC, Canada
| | - Stephanie Beram
- Department of Physics/PERFORM Center, Concordia University, Montreal, QC, Canada
| | - Uta Schneider
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Sophia Grahl
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Arno Villringer
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Clinic for Cognitive Neurology, Leipzig, Germany.,Leipzig University Medical Centre, IFB Adiposity Diseases, Leipzig, Germany.,Collaborative Research Centre 1052-A5, University of Leipzig, Leipzig, Germany
| | - Christine L Tardif
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada.,Montreal Neurological Institute, Montreal, QC, Canada
| | - Pierre-Louis Bazin
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Faculty of Social and Behavioral Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Christopher J Steele
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Department of Psychology, Concordia University, Montreal, QC, Canada
| | - Claudine J Gauthier
- Department of Physics/PERFORM Center, Concordia University, Montreal, QC, Canada. .,Montreal Heart Institute, Montreal, QC, Canada.
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24
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Islam R, Kaffman A. White-Matter Repair as a Novel Therapeutic Target for Early Adversity. Front Neurosci 2021; 15:657693. [PMID: 33897364 PMCID: PMC8062784 DOI: 10.3389/fnins.2021.657693] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/17/2021] [Indexed: 12/13/2022] Open
Abstract
Early adversity (EA) impairs myelin development in a manner that persists later in life across diverse mammalian species including humans, non-human primates, and rodents. These observations, coupled with the highly conserved nature of myelin development suggest that animal models can provide important insights into the molecular mechanisms by which EA impairs myelin development later in life and the impact of these changes on network connectivity, cognition, and behavior. However, this area of translational research has received relatively little attention and no comprehensive review is currently available to address these issues. This is particularly important given some recent mechanistic studies in rodents and the availability of new agents to increase myelination. The goals of this review are to highlight the need for additional pre-clinical work in this area and to provide specific examples that demonstrate the potential of this work to generate novel therapeutic interventions that are highly needed.
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Affiliation(s)
- Rafiad Islam
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Arie Kaffman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
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25
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Chacon-De-La-Rocha I, Fryatt G, Rivera AD, Verkhratsky A, Raineteau O, Gomez-Nicola D, Butt AM. Accelerated Dystrophy and Decay of Oligodendrocyte Precursor Cells in the APP/PS1 Model of Alzheimer's-Like Pathology. Front Cell Neurosci 2020; 14:575082. [PMID: 33343301 PMCID: PMC7744306 DOI: 10.3389/fncel.2020.575082] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/22/2020] [Indexed: 12/22/2022] Open
Abstract
Myelin disruption is a feature of natural aging and Alzheimer's disease (AD). In the CNS, myelin is produced by oligodendrocytes, which are generated throughout life by oligodendrocyte progenitor cells (OPCs). Here, we examined age-related changes in OPCs in APP/PS1 mice, a model for AD-like pathology, compared with non-transgenic (Tg) age-matched controls. The analysis was performed in the CA1 area of the hippocampus following immunolabeling for NG2 with the nuclear dye Hoescht, to identify OPC and OPC sister cells, a measure of OPC replication. The results indicate a significant decrease in the number of OPCs at 9 months in APP/PS1 mice, compared to age-matched controls, without further decline at 14 months. Also, the number of OPC sister cells declined significantly at 14 months in APP/PS1 mice, which was not observed in age-matched controls. Notably, OPCs also displayed marked morphological changes at 14 months in APP/PS1 mice, characterized by an overall shrinkage of OPC process domains and increased process branching. The results indicate that OPC disruption is a pathological sign in the APP/PS1 mouse model of AD.
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Affiliation(s)
- Irene Chacon-De-La-Rocha
- School of Pharmacy and Biomedical Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Gemma Fryatt
- School of Biological Sciences, Southampton General Hospital, University of Southampton, Portsmouth, United Kingdom
| | - Andrea D. Rivera
- School of Pharmacy and Biomedical Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, United Kingdom
| | - Olivier Raineteau
- University of Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Diego Gomez-Nicola
- School of Biological Sciences, Southampton General Hospital, University of Southampton, Portsmouth, United Kingdom
| | - Arthur M. Butt
- School of Pharmacy and Biomedical Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, United Kingdom
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26
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Beaulieu C, Yip E, Low PB, Mädler B, Lebel CA, Siegel L, Mackay AL, Laule C. Myelin Water Imaging Demonstrates Lower Brain Myelination in Children and Adolescents With Poor Reading Ability. Front Hum Neurosci 2020; 14:568395. [PMID: 33192398 PMCID: PMC7596275 DOI: 10.3389/fnhum.2020.568395] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/31/2020] [Indexed: 01/18/2023] Open
Abstract
Magnetic resonance imaging (MRI) provides a means to non-invasively investigate the neurological links with dyslexia, a learning disability that affects one’s ability to read. Most previous brain MRI studies of dyslexia and reading skill have used structural or diffusion imaging to reveal regional brain abnormalities. However, volumetric and diffusion MRI lack specificity in their interpretation at the microstructural level. Myelin is a critical neural component for brain function and plasticity, and as such, deficits in myelin may impact reading ability. MRI can estimate myelin using myelin water fraction (MWF) imaging, which is based on evaluation of the proportion of short T2 myelin-associated water from multi-exponential T2 relaxation analysis, but has not yet been applied to the study of reading or dyslexia. In this study, MWF MRI, intelligence, and reading assessments were acquired in 20 participants aged 10–18 years with a wide range of reading ability to investigate the relationship between reading ability and myelination. Group comparisons showed markedly lower MWF by 16–69% in poor readers relative to good readers in the left and right thalamus, as well as the left posterior limb of the internal capsule, left/right anterior limb of the internal capsule, left/right centrum semiovale, and splenium of the corpus callosum. MWF over the entire group also correlated positively with three different reading scores in the bilateral thalamus as well as white matter, including the splenium of the corpus callosum, left posterior limb of the internal capsule, left anterior limb of the internal capsule, and left centrum semiovale. MWF imaging from T2 relaxation suggests that myelination, particularly in the bilateral thalamus, splenium, and left hemisphere white matter, plays a role in reading abilities. Myelin water imaging thus provides a potentially valuable in vivo imaging tool for the study of dyslexia and its remediation.
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Affiliation(s)
- Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Eugene Yip
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Pauline B Low
- Department of Education and Counseling Psychology, University of British Columbia, Vancouver, BC, Canada
| | | | | | - Linda Siegel
- Department of Education and Counseling Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Alex L Mackay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Cornelia Laule
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada.,Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
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27
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Lockwood CT, Duffy CJ. Hyperexcitability in Aging Is Lost in Alzheimer's: What Is All the Excitement About? Cereb Cortex 2020; 30:5874-5884. [PMID: 32548625 DOI: 10.1093/cercor/bhaa163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Neuronal hyperexcitability has emerged as a potential biomarker of late-onset early-stage Alzheimer's disease (LEAD). We hypothesize that the aging-related posterior cortical hyperexcitability anticipates the loss of excitability with the emergence of impairment in LEAD. To test this hypothesis, we compared the behavioral and neurophysiological responses of young and older (ON) normal adults, and LEAD patients during a visuospatial attentional control task. ONs show frontal cortical signal incoherence and posterior cortical hyper-responsiveness with preserved attentional control. LEADs lose the posterior hyper-responsiveness and fail in the attentional task. Our findings suggest that signal incoherence and cortical hyper-responsiveness in aging may contribute to the development of functional impairment in LEAD.
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Affiliation(s)
- Colin T Lockwood
- Departments of Neurology and Brain and Cognitive Sciences, University of Rochester Medical Center, Rochester 14642, NY, USA
| | - Charles J Duffy
- Departments of Neurology and Brain and Cognitive Sciences, University of Rochester Medical Center, Rochester 14642, NY, USA
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28
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Sun H, Gonzalez F, McQuillen PS. Caffeine Restores Background EEG Activity Independent of Infarct Reduction after Neonatal Hypoxic Ischemic Brain Injury. Dev Neurosci 2020; 42:72-82. [PMID: 32810862 DOI: 10.1159/000509365] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 06/10/2020] [Indexed: 12/19/2022] Open
Abstract
In human preterm newborns, caffeine increases brain activity and improves neurodevelopmental outcomes. In animal models of hypoxic ischemic brain injury, caffeine pretreatment reduces infarct volume. We studied the relationship between tissue neuroprotection and brain activity after injury to further understand caffeine neuroprotection. Rat dams received caffeine prior to birth or on postnatal day 3 (P3) through P16. Caffeine-treated and -untreated pups underwent the Vannucci procedure (unilateral carotid ligation, global hypoxia) on P2. A subset had EEG recordings. Brain hemispheric infarct volume was measured on P16. P2 hypoxic ischemia (HI) results in histologic brain injury (mean ± standard deviation infarct volume 10.3 ± 4.6%) and transient suppression of EEG activity. Caffeine pretreatment reduces brain injury (mean ± standard deviation infarct volume 1.6 ± 4.5%, p < 0.001) and improves amplitude-integrated EEG (aEEG) and EEG burst duration and amplitude. Caffeine treatment after HI does not reduce infarct volume (mean ± standard deviation 8.3 ± 4.1%, p = 1.0). However, caffeine posttreatment was equally effective at restoring aEEG amplitude and EEG burst duration and amplitude. Thus, caffeine supports brain background electrical activity independent of tissue neuroprotection.
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Affiliation(s)
- Haiyan Sun
- Institute of Pediatrics, Xuzhou Medical University, Xuzhou, China
| | - Fernando Gonzalez
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA
| | - Patrick S McQuillen
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA,
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29
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Irmen F, Karabanov AN, Bögemann SA, Andersen KW, Madsen KH, Bisgaard T, Dyrby TB, Siebner HR. Functional and Structural Plasticity Co-express in a Left Premotor Region During Early Bimanual Skill Learning. Front Hum Neurosci 2020; 14:310. [PMID: 32922275 PMCID: PMC7456840 DOI: 10.3389/fnhum.2020.00310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/13/2020] [Indexed: 12/02/2022] Open
Abstract
Introduction: Motor skill learning already triggers the functional reorganization of regional brain activity after short periods of training. Recent studies suggest that microstructural change may emerge at similar timescales, but the spatiotemporal profiles of functional and structural plasticity have rarely been traced in parallel. Recently, we demonstrated that 5 days of endoscopic skill training induces changes in task-related brain activity in the ventral premotor cortex (PMv) and other areas of the frontoparietal grasping network. Here, we analyzed microstructural data, collected during the same experiment to investigate if microstructural plasticity overlaps temporally and spatially with the training-induced changes in task-related brain activity. Materials and Methods: Thirty-nine students were divided into a full-routine group (n = 20), that underwent three endoscopy training sessions in the MR-scanner as well as a 5-day virtual reality (VR)-endoscopy training and a brief-routine group (n = 19), that only performed the in-scanner endoscopy training sessions. Diffusion Tensor Imaging (DTI)-derived fractional anisotropy (FA) and resting-state functional magnetic resonance imaging (rs-fMRI) were collected at baseline, after the first and after the last VR-training session. Results: The full-routine group showed significant FA changes in a left-hemispheric subcortical cluster underlying the PMv region, for which we previously demonstrated functional plasticity during endoscopy training in the same sample. Functional (task-related fMRI) and structural (FA) changes showed the largest change from the first to the second scan, suggesting similar temporal dynamics. In the full-routine group, the FA change in the subcortical cluster underlying the left PMv scaled positively with the individual improvement in endoscopic surgery. Conclusion: Microstructural white-matter plasticity mirrors the spatiotemporal profile of task-dependent plasticity during a 5-day course of endoscopy skill training. The observed similarities motivate future research on the interplay between functional and structural plasticity during early skill acquisition.
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Affiliation(s)
- Friederike Irmen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Neurology, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Anke Ninija Karabanov
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Sophie Alida Bögemann
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Kasper Winther Andersen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Kristoffer Hougaard Madsen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Thue Bisgaard
- Surgical Department, Centre for Surgical Science, Zealand University Hospital Køge, Køge, Denmark
| | - Tim B. Dyrby
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
- Institute for Clinical Medicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark
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30
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Wilton DK, Stevens B. The contribution of glial cells to Huntington's disease pathogenesis. Neurobiol Dis 2020; 143:104963. [PMID: 32593752 DOI: 10.1016/j.nbd.2020.104963] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/07/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Glial cells play critical roles in the normal development and function of neural circuits, but in many neurodegenerative diseases, they become dysregulated and may contribute to the development of brain pathology. In Huntington's disease (HD), glial cells both lose normal functions and gain neuropathic phenotypes. In addition, cell-autonomous dysfunction elicited by mutant huntingtin (mHTT) expression in specific glial cell types is sufficient to induce both pathology and Huntington's disease-related impairments in motor and cognitive performance, suggesting that these cells may drive the development of certain aspects of Huntington's disease pathogenesis. In support of this imaging studies in pre-symptomatic HD patients and work on mouse models have suggested that glial cell dysfunction occurs at a very early stage of the disease, prior to the onset of motor and cognitive deficits. Furthermore, selectively ablating mHTT from specific glial cells or correcting for HD-induced changes in their transcriptional profile rescues some HD-related phenotypes, demonstrating the potential of targeting these cells for therapeutic intervention. Here we review emerging research focused on understanding the involvement of different glial cell types in specific aspects of HD pathogenesis. This work is providing new insight into how HD impacts biological functions of glial cells in the healthy brain as well as how HD induced dysfunction in these cells might change the way they integrate into biological circuits.
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Affiliation(s)
- Daniel K Wilton
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Beth Stevens
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Stanley Center, Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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31
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Persic D, Thomas ME, Pelekanos V, Ryugo DK, Takesian AE, Krumbholz K, Pyott SJ. Regulation of auditory plasticity during critical periods and following hearing loss. Hear Res 2020; 397:107976. [PMID: 32591097 PMCID: PMC8546402 DOI: 10.1016/j.heares.2020.107976] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/15/2020] [Accepted: 04/14/2020] [Indexed: 02/07/2023]
Abstract
Sensory input has profound effects on neuronal organization and sensory maps in the brain. The mechanisms regulating plasticity of the auditory pathway have been revealed by examining the consequences of altered auditory input during both developmental critical periods—when plasticity facilitates the optimization of neural circuits in concert with the external environment—and in adulthood—when hearing loss is linked to the generation of tinnitus. In this review, we summarize research identifying the molecular, cellular, and circuit-level mechanisms regulating neuronal organization and tonotopic map plasticity during developmental critical periods and in adulthood. These mechanisms are shared in both the juvenile and adult brain and along the length of the auditory pathway, where they serve to regulate disinhibitory networks, synaptic structure and function, as well as structural barriers to plasticity. Regulation of plasticity also involves both neuromodulatory circuits, which link plasticity with learning and attention, as well as ascending and descending auditory circuits, which link the auditory cortex and lower structures. Further work identifying the interplay of molecular and cellular mechanisms associating hearing loss-induced plasticity with tinnitus will continue to advance our understanding of this disorder and lead to new approaches to its treatment. During CPs, brain plasticity is enhanced and sensitive to acoustic experience. Enhanced plasticity can be reinstated in the adult brain following hearing loss. Molecular, cellular, and circuit-level mechanisms regulate CP and adult plasticity. Plasticity resulting from hearing loss may contribute to the emergence of tinnitus. Modifying plasticity in the adult brain may offer new treatments for tinnitus.
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Affiliation(s)
- Dora Persic
- University of Groningen, University Medical Center Groningen, Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713, GZ, Groningen, the Netherlands
| | - Maryse E Thomas
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear and Department of Otorhinolaryngology and Head/Neck Surgery, Harvard Medical School, Boston, MA, USA
| | - Vassilis Pelekanos
- Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, University Park, Nottingham, UK
| | - David K Ryugo
- Hearing Research, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia; School of Medical Sciences, UNSW Sydney, Sydney, NSW, 2052, Australia; Department of Otolaryngology, Head, Neck & Skull Base Surgery, St Vincent's Hospital, Sydney, NSW, 2010, Australia
| | - Anne E Takesian
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear and Department of Otorhinolaryngology and Head/Neck Surgery, Harvard Medical School, Boston, MA, USA
| | - Katrin Krumbholz
- Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, University Park, Nottingham, UK
| | - Sonja J Pyott
- University of Groningen, University Medical Center Groningen, Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713, GZ, Groningen, the Netherlands.
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32
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Spencer SA, Suárez-Pozos E, Escalante M, Myo YP, Fuss B. Sodium-Calcium Exchangers of the SLC8 Family in Oligodendrocytes: Functional Properties in Health and Disease. Neurochem Res 2020; 45:1287-1297. [PMID: 31927687 DOI: 10.1007/s11064-019-02949-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/30/2022]
Abstract
The solute carrier 8 (SLC8) family of sodium-calcium exchangers (NCXs) functions as an essential regulatory system that couples opposite fluxes of sodium and calcium ions across plasmalemmal membranes. NCXs, thereby, play key roles in maintaining an ion homeostasis that preserves cellular integrity. Hence, alterations in NCX expression and regulation have been found to lead to ionic imbalances that are often associated with intracellular calcium overload and cell death. On the other hand, intracellular calcium has been identified as a key driver for a multitude of downstream signaling events that are crucial for proper functioning of biological systems, thus highlighting the need for a tightly controlled balance. In the CNS, NCXs have been primarily characterized in the context of synaptic transmission and ischemic brain damage. However, a much broader picture is emerging. NCXs are expressed by virtually all cells of the CNS including oligodendrocytes (OLGs), the cells that generate the myelin sheath. With a growing appreciation of dynamic calcium signals in OLGs, NCXs are becoming increasingly recognized for their crucial roles in shaping OLG function under both physiological and pathophysiological conditions. In order to provide a current update, this review focuses on the importance of NCXs in cells of the OLG lineage. More specifically, it provides a brief introduction into plasmalemmal NCXs and their modes of activity, and it discusses the roles of OLG expressed NCXs in regulating CNS myelination and in contributing to CNS pathologies associated with detrimental effects on OLG lineage cells.
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Affiliation(s)
- Samantha A Spencer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Edna Suárez-Pozos
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Miguel Escalante
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.,Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Yu Par Myo
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.
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33
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de Vivo L, Bellesi M. The role of sleep and wakefulness in myelin plasticity. Glia 2019; 67:2142-2152. [PMID: 31237382 PMCID: PMC6771952 DOI: 10.1002/glia.23667] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/17/2022]
Abstract
Myelin plasticity is gaining increasing recognition as an essential partner to synaptic plasticity, which mediates experience-dependent brain structure and function. However, how neural activity induces adaptive myelination and which mechanisms are involved remain open questions. More than two decades of transcriptomic studies in rodents have revealed that hundreds of brain transcripts change their expression in relation to the sleep-wake cycle. These studies consistently report upregulation of myelin-related genes during sleep, suggesting that sleep represents a window of opportunity during which myelination occurs. In this review, we summarize recent molecular and morphological studies detailing the dependence of myelin dynamics after sleep, wake, and chronic sleep loss, a condition that can affect myelin substantially. We present novel data about the effects of sleep loss on the node of Ranvier length and provide a hypothetical mechanism through which myelin changes in response to sleep loss. Finally, we discuss the current findings in humans, which appear to confirm the important role of sleep in promoting white matter integrity.
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Affiliation(s)
- Luisa de Vivo
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Michele Bellesi
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
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Bells S, Lefebvre J, Longoni G, Narayanan S, Arnold DL, Yeh EA, Mabbott DJ. White matter plasticity and maturation in human cognition. Glia 2019; 67:2020-2037. [PMID: 31233643 DOI: 10.1002/glia.23661] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 12/17/2022]
Abstract
White matter plasticity likely plays a critical role in supporting cognitive development. However, few studies have used the imaging methods specific to white matter tissue structure or experimental designs sensitive to change in white matter necessary to elucidate these relations. Here we briefly review novel imaging approaches that provide more specific information regarding white matter microstructure. Furthermore, we highlight recent studies that provide greater clarity regarding the relations between changes in white matter and cognition maturation in both healthy children and adolescents and those with white matter insult. Finally, we examine the hypothesis that white matter is linked to cognitive function via its impact on neural synchronization. We test this hypothesis in a population of children and adolescents with recurrent demyelinating syndromes. Specifically, we evaluate group differences in white matter microstructure within the optic radiation; and neural phase synchrony in visual cortex during a visual task between 25 patients and 28 typically developing age-matched controls. Children and adolescents with demyelinating syndromes show evidence of myelin and axonal compromise and this compromise predicts reduced phase synchrony during a visual task compared to typically developing controls. We investigate one plausible mechanism at play in this relationship using a computational model of gamma generation in early visual cortical areas. Overall, our findings show a fundamental connection between white matter microstructure and neural synchronization that may be critical for cognitive processing. In the future, longitudinal or interventional studies can build upon our knowledge of these exciting relations between white matter, neural communication, and cognition.
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Affiliation(s)
- Sonya Bells
- Neurosciences and Mental Health Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jérémie Lefebvre
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Department of Mathematics, University of Toronto, Toronto, Ontario, Canada
| | - Giulia Longoni
- Neurosciences and Mental Health Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Sridar Narayanan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Douglas L Arnold
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Eleun Ann Yeh
- Neurosciences and Mental Health Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Donald J Mabbott
- Neurosciences and Mental Health Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
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Turner R. Myelin and Modeling: Bootstrapping Cortical Microcircuits. Front Neural Circuits 2019; 13:34. [PMID: 31133821 PMCID: PMC6517540 DOI: 10.3389/fncir.2019.00034] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 04/25/2019] [Indexed: 12/15/2022] Open
Abstract
Histological studies of myelin-stained sectioned cadaver brain and in vivo myelin-weighted magnetic resonance imaging (MRI) show that the cerebral cortex is organized into cortical areas with generally well-defined boundaries, which have consistent internal patterns of myelination. The process of myelination is largely driven by neural experience, in which the axonal passage of action potentials stimulates neighboring oligodendrocytes to perform their task. This bootstrapping process, such that the traffic of action potentials facilitates increased traffic, suggests the hypothesis that the specific pattern of myelination (myeloarchitecture) in each cortical area reveals the principal cortical microcircuits required for the function of that area. If this idea is correct, the observable sequential maturation of specific brain areas can provide evidence for models of the stages of cognitive development.
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Affiliation(s)
- Robert Turner
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom
- Spinoza Centre for Neuroimaging, University of Amsterdam, Amsterdam, Netherlands
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Abstract
Oligodendrocytes are the myelinating cells of the CNS, producing the insulating myelin sheath that facilitates rapid electrical conduction of axonal action potentials. Oligodendrocytes arise from oligodendrocyte progenitor cells (OPCs) under the control of multiple factors, including neurotransmitters and other neuron-derived factors. A significant population of OPCs persists in the adult CNS, where they are often referred to as NG2-glia, because they are identified by their expression of the NG2 chondroitin sulphate proteoglycan (CSPG4). In the adult brain, the primary function of NG2-glia is the life-long generation of oligodendrocytes to replace myelin lost through natural 'wear and tear' and pathology, as well as to provide new oligodendrocytes to myelinate new connections formed in response to new life experiences. NG2-glia contact synapses and respond to neurotransmitters and potassium released during neuronal transmission; to this end, NG2-glia (OPCs) express multiple neurotransmitter receptors and ion channels, with prominent roles being identified for glutamatergic signalling and potassium channels in oligodendrocyte differentiation. Myelinating oligodendrocytes also express a wide range of neurotransmitter receptors and ion channels, together with transporters and gap junctions; together, these have critical functions in cellular ion and water homeostasis, as well as metabolism, which is essential for maintaining myelin and axon integrity. An overriding theme is that oligodendrocyte function and myelination is not only essential for rapid axonal conduction, but is essential for learning and the long-term integrity of axons and neurones. Hence, myelination underpins cognitive function and the massive computing power of the human brain and myelin loss has devastating effects on CNS function. This chapter focuses on normal oligodendrocyte physiology.
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Butt AM, De La Rocha IC, Rivera A. Oligodendroglial Cells in Alzheimer's Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:325-333. [PMID: 31583593 DOI: 10.1007/978-981-13-9913-8_12] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Oligodendrocytes form the myelin that ensheaths CNS axons, which is essential for rapid neuronal signalling and underpins the massive computing power of the human brain. Oligodendrocytes and myelin also provide metabolic and trophic support for axons and their disruption results in axonal demise and neurodegeneration, which are key features of Alzheimer's disease (AD). Notably, the brain has a remarkable capacity for regenerating oligodendrocytes, which is the function of adult oligodendrocyte progenitor cells (OPCs) or NG2-glia. White matter loss is often among the earliest brain changes in AD, preceding the tangles and plaques that characterize neuronal deficits. The underlying causes of myelin loss include oxidative stress, neuroinflammation and excitotoxicity, associated with accumulation of Aβ and tau hyperphosphorylation, pathological hallmarks of AD. Moreover, there is evidence that NG2-glia are disrupted in AD, which may be associated with disruption of synaptic signalling. This has led to the hypothesis that a vicious cycle of myelin loss and failure of regeneration from NG2-glia plays a key role in AD. Therapies that target NG2-glia are likely to have positive effects on myelination and neuroprotection in AD.
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Affiliation(s)
- Arthur M Butt
- School of Pharmacy and Biomedical Science, University of Portsmouth, St. Michael's Building, White Sawn Road, Portsmouth, PO1 2DT, UK.
| | - Irene Chacon De La Rocha
- School of Pharmacy and Biomedical Science, University of Portsmouth, St. Michael's Building, White Sawn Road, Portsmouth, PO1 2DT, UK
| | - Andrea Rivera
- School of Pharmacy and Biomedical Science, University of Portsmouth, St. Michael's Building, White Sawn Road, Portsmouth, PO1 2DT, UK
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