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Apparent diffusion coefficient changes in human brain during sleep – Does it inform on the existence of a glymphatic system?

Şükrü Barış Demiral, Dardo Tomasi, Joelle Sarlls, Hedok Lee, Corinde E. Wiers, Amna Zehra, Tansha Srivastava, Kenneth Ke, Ehsan Shokri-Kojori, Clara R. Freeman, Elsa Lindgren, Veronica Ramirez (+6 others)
2019 NeuroImage  
On the other hand, our findings of sleep-induced changes in CSF volume provide preliminary evidence that is consistent with a glymphatic transport process in the human brain.  ...  We used MRI to measure slow and fast components of the apparent diffusion coefficient (ADC) of water in the brain in 50 healthy participants, in 30 of whom we compared awake versus sleep conditions and  ...  We also thank Okan Irfanoglu and Amritha Nayak for their help in diffusion data processing. We also thank Peter Manza for his suggestions in figure preparation and discussion of the findings.  ... 
doi:10.1016/j.neuroimage.2018.10.043 pmid:30342236 pmcid:PMC6289767 fatcat:ai4nuawfuncqjomjgefglpf6ei

Glymphatic Dysfunction: A Bridge Between Sleep Disturbance and Mood Disorders

Tao Yan, Yuefeng Qiu, Xinfeng Yu, Linglin Yang
2021 Frontiers in Psychiatry  
Recent discovery of the glymphatic system and its dynamic fluctuation with sleep provide a plausible explanation.  ...  The diurnal variation of the glymphatic circulation is dependent on the astrocytic activity and polarization of water channel protein aquaporin-4 (AQP4).  ...  However, several limitations exist in this study. First, much of the existing evidence on the glymphatic system has been conducted in rodents and only a few in humans.  ... 
doi:10.3389/fpsyt.2021.658340 pmid:34025481 pmcid:PMC8138157 fatcat:pswpypqrbnbx3c3ortnafpcaq4

The role of brain barriers in fluid movement in the CNS: is there a 'glymphatic' system?

N. Joan Abbott, Michelle E. Pizzo, Jane E. Preston, Damir Janigro, Robert G. Thorne
2018 Acta Neuropathologica  
This review discusses studies which question the role of AQP4 in ISF flow and the lack of evidence for its ability to transport solutes; summarizes attributes of brain ECS that strongly favour the diffusion  ...  'glymphatic' concepts in favour of a new system better taking into account basic cerebrovascular physiology and fluid transport considerations.  ...  Acknowledgements This work was supported by the University of  ... 
doi:10.1007/s00401-018-1812-4 pmid:29428972 fatcat:yxr6osugsndybpjuhcp6jpjn5q

Spatial model of convective solute transport in brain extracellular space does not support a "glymphatic" mechanism

Byung-Ju Jin, Alex J. Smith, Alan S. Verkman
2016 The Journal of General Physiology  
Here, we investigate the major predictions of the glymphatic mechanism by modeling diffusive and convective transport in brain ECS and by solving the Navier–Stokes and convection–diffusion equations, using  ...  The model predicts solute accumulation and clearance from the ECS after a step change in solute concentration in para-arterial fluid.  ...  Changes in the size of the ECS during sleep have been proposed to activate the glymphatic system to clear unwanted solutes from the ECS, offering a novel role for sleep (Xie et al., 2013) .  ... 
doi:10.1085/jgp.201611684 pmid:27836940 pmcid:PMC5129742 fatcat:xpajbplnn5eqrm5kq7vpr4bdwe

Current Techniques for Investigating the Brain Extracellular Space

Federico N. Soria, Cristina Miguelez, Olga Peñagarikano, Jan Tønnesen
2020 Frontiers in Neuroscience  
The brain extracellular space (ECS) is a continuous reticular compartment that lies between the cells of the brain.  ...  Our conventional view of this compartment as largely static and of secondary importance for brain function is rapidly changing, and its active dynamic roles in signaling and metabolite clearance have come  ...  In humans, intrathecal infusion of an MRI tracer revealed a brain-wide drainage of CSF to the cervical nodes, thereby corroborating the existence of a functional glymphatic system also in humans (Eide  ... 
doi:10.3389/fnins.2020.570750 pmid:33177979 pmcid:PMC7591815 fatcat:gtzzj35fiffa3f4hu5fm4pu6cq

Evidence for wakefulness-related changes to extracellular space in human brain white matter from diffusion-weighted MRI

Irene Voldsbekk, Ivan I. Maximov, Nathalia Zak, Daniel Roelfs, Oliver Geier, Paulina Due-Tønnessen, Torbjørn Elvsåshagen, Marie Strømstad, Atle Bjørnerud, Inge Groote
2020 NeuroImage  
Recently, several magnetic resonance imaging (MRI) studies have reported time-of-day effects on brain structure and function.  ...  In addition, the current study assessed whether time-of-day effects were driven by changes to extracellular space, by including estimations of non-Gaussian diffusion metrics obtained from diffusion kurtosis  ...  Acknowledgements This project was funded by a research grant from the Norwegian South-East Health Authorities (2017090), and by the Research Council of Norway (249795).  ... 
doi:10.1016/j.neuroimage.2020.116682 pmid:32114147 fatcat:poofuiwswzafvnngkl55cgtmmm

Glymphatic MRI in idiopathic normal pressure hydrocephalus

Geir Ringstad, Svein Are Sirirud Vatnehol, Per Kristian Eide
2017 Brain  
The glymphatic system has in previous studies been shown as fundamental to clearance of waste metabolites from the brain interstitial space, and is proposed to be instrumental in normal ageing and brain  ...  We aimed to image cerebrospinal fluid flow characteristics and glymphatic function in humans, and applied the methodology in a prospective study of 15 idiopathic normal pressure hydrocephalus patients  ...  Supplementary material Supplementary material is available at Brain online. Glymphatic MRI in iNPH BRAIN 2017: 140; 2691-2705 | 2703  ... 
doi:10.1093/brain/awx191 pmid:28969373 pmcid:PMC5841149 fatcat:sicgvhm5unhkdenuhufxniyr3a

Quantitative analysis of macroscopic solute transport in the murine brain

Lori A. Ray, Martin Pike, Matthew Simon, Jeffrey J. Iliff, Jeffrey J. Heys
2021 Fluids and Barriers of the CNS  
The set of regional effective diffusivities ($$D_{eff}$$ D eff ), a transport parameter combining all mechanisms of transport, that best represent the experimental data are determined and compared to apparent  ...  diffusivity ($$D_{app}$$ D app ), the known rate of diffusion through brain tissue, to draw conclusions about dominant transport mechanisms in each region.  ...  the right-hand side of Eq. 3): where c = concentration, D app = apparent diffusivity, D disp = dispersion coefficient, v = superficial velocity (a vector field), s(c) = spatially dependent source term  ... 
doi:10.1186/s12987-021-00290-z pmid:34876169 pmcid:PMC8650464 fatcat:r7pogubmwjbobo27od6nni2eki

Lymphatic Clearance of the Brain: Perivascular, Paravascular and Significance for Neurodegenerative Diseases

Erik N. T. P. Bakker, Brian J. Bacskai, Michal Arbel-Ornath, Roxana Aldea, Beatrice Bedussi, Alan W. J. Morris, Roy O. Weller, Roxana O. Carare
2016 Cellular and molecular neurobiology  
Recent work suggests that clearance of the brain mainly occurs during sleep, with a specific role for peri-and para-vascular spaces as drainage pathways from the brain parenchyma.  ...  The different views on the possible routes for ISF drainage of the brain are discussed in the context of pathological significance.  ...  The apparent diffusion coefficient (D Ã ) compared to the diffusion coefficient in water (D) is measured by tortuosity (k).  ... 
doi:10.1007/s10571-015-0273-8 pmid:26993512 pmcid:PMC4844641 fatcat:eefww2zb2ndz3bl3imlkdophva

Advanced Diffusion MRI of the Visual System in Glaucoma: From Experimental Animal Models to Humans

Monica Mendoza, Max Shotbolt, Muneeb A. Faiq, Carlos Parra, Kevin C. Chan
2022 Biology  
A growing body of dMRI research indicates that this modality holds promise in characterizing early glaucomatous changes in the visual system, determining the disease severity, and identifying potential  ...  In this review, we discuss dMRI methods currently used in visual system investigations, focusing on the eye, optic nerve, optic tract, subcortical visual brain nuclei, optic radiations, and visual cortex  ...  Acknowledgments: We thank all collaborators who contributed to our research papers upon which the present commentary is based. Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/biology11030454 pmid:35336827 pmcid:PMC8945790 fatcat:iuqpsty4efamto5qq5e7eaufpi

Mechanisms of fluid movement into, through and out of the brain: evaluation of the evidence

Stephen B Hladky, Margery A Barrand
2014 Fluids and Barriers of the CNS  
that secrete fluid of controlled composition into the brain and distribute and reabsorb it.  ...  Modern techniques have revealed complex fluid movements within the brain. This review provides a critical evaluation of the data.  ...  and 4.4.2, TG-M for a preprint of his poster on possible explanations of the TMA results and for pointing out to us the extremely rapid nature of the volume changes being inferred by Xie et al  ... 
doi:10.1186/2045-8118-11-26 pmid:25678956 pmcid:PMC4326185 fatcat:xgrozkocmbaxhju4nnh22ldmee

Elimination of substances from the brain parenchyma: efflux via perivascular pathways and via the blood–brain barrier

Stephen B. Hladky, Margery A. Barrand
2018 Fluids and Barriers of the CNS  
Total clearance of a substance is the sum of clearance values for all available routes including perivascular pathways and the blood-brain barrier.  ...  This review considers efflux of substances from brain parenchyma quantified as values of clearances (CL, stated in µL g −1 min −1 ).  ...  In order for the system to be modified some sort of signal is required 'to inform' the elimination system that the input and/or the concentration has changed.  ... 
doi:10.1186/s12987-018-0113-6 fatcat:ysmziuqfe5dn5homx3r63sqbhq

Autonomic arousals contribute to brain fluid pulsations during sleep [article]

Dante Picchioni, Pinar S. Özbay, Hendrik Mandelkow, Jacco A. de Zwart, Yicun Wang, Peter van Gelderen, Jeff H. Duyn
2021 bioRxiv   pre-print
AbstractDuring sleep, slow waves of neuro-electrical activity engulf the human brain and aid in the consolidation of memories.  ...  To investigate the role of slow waves in the generation of CSF pulsations, we analyzed functional MRI data obtained across the full sleep-wake cycle and during a respiratory task during wakefulness.  ...  It seems therefore likely that the absolute change in the level of neuronal firing during a slow 11 wave does not exceed that during a strong stimulus of equal duration. 13 Note 6: CSF displacement from  ... 
doi:10.1101/2021.05.04.442672 fatcat:bxpbfbxotbgm5pjem22uvawfhi

A deeper look into natural sciences with physics-based and data-driven measures

Davi Röhe Rodrigues, Karin Everschor-Sitte, Susanne Gerber, Illia Horenko
2021 iScience  
and a latent network of glymphatic channels from the mouse brain microscopy data.  ...  With the development of machine learning in recent years, it is possible to glean much more information from an experimental data set to study matter.  ...  ACKNOWLEDGMENTS We would like to thank the group of M. Klä ui, in particular J. Zazvorká , for discussions and contributing with the experimental data used in Figure 4 .  ... 
doi:10.1016/j.isci.2021.102171 pmid:33665584 pmcid:PMC7907479 fatcat:l47w7qmbkfg4bexhcx7jdlcgqa

Military traumatic brain injury: a challenge straddling neurology and psychiatry

Ling-Zhuo Kong, Rui-Li Zhang, Shao-Hua Hu, Jian-Bo Lai
2022 Military Medical Research  
To date, advances in neuroimaging and molecular biology have greatly boosted the studies on military traumatic brain injury (TBI).  ...  AbstractMilitary psychiatry, a new subcategory of psychiatry, has become an invaluable, intangible effect of the war.  ...  All authors read and approved the final manuscript.  ... 
doi:10.1186/s40779-021-00363-y pmid:34991734 pmcid:PMC8740337 fatcat:6v42ox4dozgujji7rfjwpxqrie
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