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Kuo DP, Chen YC, Cheng SJ, Hsieh KLC, Ou CY, Li YT, Chen CY. Ischemia-reperfusion injury in a salvaged penumbra: Longitudinal high-tesla perfusion magnetic resonance imaging in a rat model. Magn Reson Imaging 2024; 112:47-53. [PMID: 38909765 DOI: 10.1016/j.mri.2024.06.003] [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] [Received: 04/18/2024] [Revised: 05/23/2024] [Accepted: 06/20/2024] [Indexed: 06/25/2024]
Abstract
INTRODUCTION Although ischemia-reperfusion (I/R) injury varies between cortical and subcortical regions, its effects on specific regions remain unclear. In this study, we used various magnetic resonance imaging (MRI) techniques to examine the spatiotemporal dynamics of I/R injury within the salvaged ischemic penumbra (IP) and reperfused ischemic core (IC) of a rodent model, with the aim of enhancing therapeutic strategies by elucidating these dynamics. MATERIALS AND METHODS A total of 17 Sprague-Dawley rats were subjected to 1 h of transient middle cerebral artery occlusion with a suture model. MRI, including diffusion tensor imaging (DTI), T2-weighted imaging, perfusion-weighted imaging, and T1 mapping, was conducted at multiple time points for up to 5 days during the I/R phases. The spatiotemporal dynamics of blood-brain barrier (BBB) modifications were characterized through changes in T1 within the IP and IC regions and compared with mean diffusivity (MD), T2, and cerebral blood flow. RESULTS During the I/R phases, the MD of the IC initially decreased, normalized after recanalization, decreased again at 24 h, and peaked on day 5. By contrast, the IP remained relatively stable. Both the IP and IC exhibited hyperperfusion, with the IP reaching its peak at 24 h, followed by resolution, whereas hyperperfusion was maintained in the IC until day 5. Despite hyperperfusion, the IP maintained an intact BBB, whereas the IC experienced persistent BBB leakage. At 24 h, the IC exhibited an increase in the T2 signal, corresponding to regions exhibiting BBB disruption at 5 days. CONCLUSIONS Hyperperfusion and BBB impairment have distinct patterns in the IP and IC. Quantitative T1 mapping may serve as a supplementary tool for the early detection of malignant hyperemia accompanied by BBB leakage, aiding in precise interventions after recanalization. These findings underscore the value of MRI markers in monitoring ischemia-specific regions and customizing therapeutic strategies to improve patient outcomes.
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Affiliation(s)
- Duen-Pang Kuo
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yung-Chieh Chen
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sho-Jen Cheng
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Kevin Li-Chun Hsieh
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chen-Yin Ou
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Yi-Tien Li
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Research Center for Neuroscience, Taipei Medical University, Taipei, Taiwan; Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
| | - Cheng-Yu Chen
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Research Center for Artificial Intelligence in Medicine, Taipei Medical University, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Radiology, National Defense Medical Center, Taipei, Taiwan
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Le Bihan D. From Brownian motion to virtual biopsy: a historical perspective from 40 years of diffusion MRI. Jpn J Radiol 2024:10.1007/s11604-024-01642-z. [PMID: 39289243 DOI: 10.1007/s11604-024-01642-z] [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: 07/15/2024] [Accepted: 08/07/2024] [Indexed: 09/19/2024]
Abstract
Diffusion MRI was introduced in 1985, showing how the diffusive motion of molecules, especially water, could be spatially encoded with MRI to produce images revealing the underlying structure of biologic tissues at a microscopic scale. Diffusion is one of several Intravoxel Incoherent Motions (IVIM) accessible to MRI together with blood microcirculation. Diffusion imaging first revolutionized the management of acute cerebral ischemia by allowing diagnosis at an acute stage when therapies can still work, saving the outcomes of many patients. Since then, the field of diffusion imaging has expanded to the whole body, with broad applications in both clinical and research settings, providing insights into tissue integrity, structural and functional abnormalities from the hindered diffusive movement of water molecules in tissues. Diffusion imaging is particularly used to manage many neurologic disorders and in oncology for detecting and classifying cancer lesions, as well as monitoring treatment response at an early stage. The second major impact of diffusion imaging concerns the wiring of the brain (Diffusion Tensor Imaging, DTI), allowing to obtain from the anisotropic movement of water molecules in the brain white-matter images in 3 dimensions of the brain connections making up the Connectome. DTI has opened up new avenues of clinical diagnosis and research to investigate brain diseases, neurogenesis and aging, with a rapidly extending field of application in psychiatry, revealing how mental illnesses could be seen as Connectome spacetime disorders. Adding that water diffusion is closely associated to neuronal activity, as shown from diffusion fMRI, one may consider that diffusion MRI is ideally suited to investigate both brain structure and function. This article retraces the early days and milestones of diffusion MRI which spawned over 40 years, showing how diffusion MRI emerged and expanded in the research and clinical fields, up to become a pillar of modern clinical imaging.
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Affiliation(s)
- Denis Le Bihan
- NeuroSpin, CEA, Paris-Saclay University, Bât 145, CEA-Saclay Center, 91191, Gif-sur-Yvette, France.
- Human Brain Research Center, Kyoto University, Kyoto, Japan.
- Department of System Neuroscience, National Institutes for Physiological Sciences, Okazaki, Japan.
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Mirasierra M, Fernández-Pérez A, Lizarbe B, Keiran N, Ruiz-Cañas L, Casarejos MJ, Cerdán S, Vendrell J, Fernández-Veledo S, Vallejo M. Alx3 deficiency disrupts energy homeostasis, alters body composition, and impairs hypothalamic regulation of food intake. Cell Mol Life Sci 2024; 81:343. [PMID: 39129011 PMCID: PMC11335267 DOI: 10.1007/s00018-024-05384-z] [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: 07/10/2023] [Revised: 07/03/2024] [Accepted: 07/27/2024] [Indexed: 08/13/2024]
Abstract
The coordination of food intake, energy storage, and expenditure involves complex interactions between hypothalamic neurons and peripheral tissues including pancreatic islets, adipocytes, muscle, and liver. Previous research shows that deficiency of the transcription factor Alx3 alters pancreatic islet-dependent glucose homeostasis. In this study we carried out a comprehensive assessment of metabolic alterations in Alx3 deficiency. We report that Alx3-deficient mice exhibit decreased food intake without changes in body weight, along with reduced energy expenditure and altered respiratory exchange ratio. Magnetic resonance imaging reveals increased adiposity and decreased muscle mass, which was associated with markers of motor and sympathetic denervation. By contrast, Alx3-deficient mice on a high-fat diet show attenuated weight gain and improved insulin sensitivity, compared to control mice. Gene expression analysis demonstrates altered lipogenic and lipolytic gene profiles. In wild type mice Alx3 is expressed in hypothalamic arcuate nucleus neurons, but not in major peripheral metabolic organs. Functional diffusion-weighted magnetic resonance imaging reveals selective hypothalamic responses to fasting in the arcuate nucleus of Alx3-deficient mice. Additionally, altered expression of proopiomelanocortin and melanocortin-3 receptor mRNA in the hypothalamus suggests impaired regulation of feeding behavior. This study highlights the crucial role for Alx3 in governing food intake, energy homeostasis, and metabolic nutrient partitioning, thereby influencing body mass composition.
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Affiliation(s)
- Mercedes Mirasierra
- Instituto de Investigaciones Biomédicas Sols-Morreale, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio Fernández-Pérez
- Instituto de Investigaciones Biomédicas Sols-Morreale, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
- Centro para el Desarrollo Tecnológico e Industrial (CDTI), Madrid, Spain
| | - Blanca Lizarbe
- Instituto de Investigaciones Biomédicas Sols-Morreale, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid, Spain
- Department of Biochemistry, Universidad Autónoma de Madrid, Madrid, Spain
| | - Noelia Keiran
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
- Department of Endocrinology and Nutrition, Research Unit, Institut d'Investigació Sanitària Pere Virgili (IISPV) - Hospital Universitari de Tarragona Joan XXIII, Universitat Rovira i Virgili, Tarragona, Spain
| | - Laura Ruiz-Cañas
- Instituto de Investigaciones Biomédicas Sols-Morreale, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid, Spain
- Chronic Diseases and Cancer Area 3, Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - María José Casarejos
- Neuropharmacology Laboratory, Neurobiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - Sebastián Cerdán
- Instituto de Investigaciones Biomédicas Sols-Morreale, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid, Spain
| | - Joan Vendrell
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
- Department of Endocrinology and Nutrition, Research Unit, Institut d'Investigació Sanitària Pere Virgili (IISPV) - Hospital Universitari de Tarragona Joan XXIII, Universitat Rovira i Virgili, Tarragona, Spain
| | - Sonia Fernández-Veledo
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
- Department of Endocrinology and Nutrition, Research Unit, Institut d'Investigació Sanitària Pere Virgili (IISPV) - Hospital Universitari de Tarragona Joan XXIII, Universitat Rovira i Virgili, Tarragona, Spain
| | - Mario Vallejo
- Instituto de Investigaciones Biomédicas Sols-Morreale, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain.
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Sun YW, Lyu XY, Lei XY, Huang MM, Wang ZM, Gao B. Association study of brain structure-function coupling and glymphatic system function in patients with mild cognitive impairment due to Alzheimer's disease. Front Neurosci 2024; 18:1417986. [PMID: 39139498 PMCID: PMC11320604 DOI: 10.3389/fnins.2024.1417986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 07/17/2024] [Indexed: 08/15/2024] Open
Abstract
Background Mild cognitive impairment (MCI) is a critical transitional phase from healthy cognitive aging to dementia, offering a unique opportunity for early intervention. However, few studies focus on the correlation of brain structure and functional activity in patients with MCI due to Alzheimer's disease (AD). Elucidating the complex interactions between structural-functional (SC-FC) brain connectivity and glymphatic system function is crucial for understanding this condition. Method The aims of this study were to explore the relationship among SC-FC coupling values, glymphatic system function and cognitive function. 23 MCI patients and 18 healthy controls (HC) underwent diffusion tensor imaging (DTI) and resting-state functional MRI (fMRI). DTI analysis along the perivascular space (DTI-ALPS) index and SC-FC coupling values were calculated using DTI and fMRI. Correlation analysis was conducted to assess the relationship between Mini-Mental State Examination (MMSE) scores, DTI-ALPS index, and coupling values. Receiver operating characteristic (ROC) curves was conducted on the SC-FC coupling between the whole brain and subnetworks. The correlation of coupling values with MMSE scores was also analyzed. Result MCI patients (67.74 ± 6.99 years of age) exhibited significantly lower coupling in the whole-brain network and subnetworks, such as the somatomotor network (SMN) and ventral attention network (VAN), than HCs (63.44 ± 6.92 years of age). Whole-brain network coupling was positively correlated with dorsal attention network (DAN), SMN, and visual network (VN) coupling. MMSE scores were significantly positively correlated with whole-brain coupling and SMN coupling. In MCI, whole-brain network demonstrated the highest performance, followed by the SMN and VAN, with the VN, DAN, limbic network (LN), frontoparietal network (FPN), and default mode network (DMN). Compared to HCs, lower DTI-ALPS index was observed in individuals with MCI. Additionally, the left DTI-ALPS index showed a significant positive correlation with MMSE scores and coupling values in the whole-brain network and SMN. Conclusion These findings reveal the critical role of SC-FC coupling values and the ALPS index in cognitive function of MCI. The positive correlations observed in the left DTI-ALPS and whole-brain and SMN coupling values provide a new insight for investigating the asymmetrical nature of cognitive impairments.
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Affiliation(s)
- Yong-Wen Sun
- Department of Radiology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Xin-Yue Lyu
- Department of Radiology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Xiao-Yang Lei
- Department of Neurology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Ming-Ming Huang
- Department of Radiology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Zhen-Min Wang
- Key Laboratory of Brain Imaging, Guizhou Medical University, Guiyang, China
| | - Bo Gao
- Department of Radiology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
- Key Laboratory of Brain Imaging, Guizhou Medical University, Guiyang, China
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5
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Luppi AI, Rosas FE, Mediano PAM, Demertzi A, Menon DK, Stamatakis EA. Unravelling consciousness and brain function through the lens of time, space, and information. Trends Neurosci 2024; 47:551-568. [PMID: 38824075 DOI: 10.1016/j.tins.2024.05.007] [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] [Received: 02/15/2024] [Revised: 04/29/2024] [Accepted: 05/09/2024] [Indexed: 06/03/2024]
Abstract
Disentangling how cognitive functions emerge from the interplay of brain dynamics and network architecture is among the major challenges that neuroscientists face. Pharmacological and pathological perturbations of consciousness provide a lens to investigate these complex challenges. Here, we review how recent advances about consciousness and the brain's functional organisation have been driven by a common denominator: decomposing brain function into fundamental constituents of time, space, and information. Whereas unconsciousness increases structure-function coupling across scales, psychedelics may decouple brain function from structure. Convergent effects also emerge: anaesthetics, psychedelics, and disorders of consciousness can exhibit similar reconfigurations of the brain's unimodal-transmodal functional axis. Decomposition approaches reveal the potential to translate discoveries across species, with computational modelling providing a path towards mechanistic integration.
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Affiliation(s)
- Andrea I Luppi
- Division of Anaesthesia, University of Cambridge, Cambridge, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Montreal Neurological Institute, McGill University, Montreal, QC, Canada; St John's College, University of Cambridge, Cambridge, UK; Center for Eudaimonia and Human Flourishing, Linacre College, University of Oxford, Oxford, UK.
| | - Fernando E Rosas
- Center for Eudaimonia and Human Flourishing, Linacre College, University of Oxford, Oxford, UK; Department of Informatics, University of Sussex, Brighton, UK; Center for Psychedelic Research, Imperial College London, London, UK
| | | | - Athena Demertzi
- Physiology of Cognition Lab, GIGA-Cyclotron Research Center In Vivo Imaging, University of Liège, Liège 4000, Belgium; Psychology and Neuroscience of Cognition Research Unit, University of Liège, Liège 4000, Belgium; National Fund for Scientific Research (FNRS), Brussels 1000, Belgium
| | - David K Menon
- Division of Anaesthesia, University of Cambridge, Cambridge, UK
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, University of Cambridge, Cambridge, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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6
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Zhu Y, Jing L, Hu R, Mo F, Jia Q, Yang G, Xu Z, Han M, Wang M, Cai X, Luo J. High-Throughput Microelectrode Arrays for Precise Functional Localization of the Globus Pallidus Internus. CYBORG AND BIONIC SYSTEMS 2024; 5:0123. [PMID: 38784125 PMCID: PMC11112599 DOI: 10.34133/cbsystems.0123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/09/2024] [Indexed: 05/25/2024] Open
Abstract
The globus pallidus internus (GPi) was considered a common target for stimulation in Parkinson's disease (PD). Located deep in the brain and of small size, pinpointing it during surgery is challenging. Multi-channel microelectrode arrays (MEAs) can provide micrometer-level precision functional localization, which can maximize the surgical outcome. In this paper, a 64-channel MEA modified by platinum nanoparticles with a detection site impedance of 61.1 kΩ was designed and prepared, and multiple channels could be synchronized to cover the target brain region and its neighboring regions so that the GPi could be identified quickly and accurately. The results of the implant trajectory indicate that, compared to the control side, there is a reduction in local field potential (LFP) power in multiple subregions of the upper central thalamus on the PD-induced side, while the remaining brain regions exhibit an increasing trend. When the MEA tip was positioned at 8,700 μm deep in the brain, the various characterizations of the spike signals, combined with the electrophysiological characteristics of the β-segmental oscillations in PD, enabled MEAs to localize the GPi at the single-cell level. More precise localization could be achieved by utilizing the distinct characteristics of the internal capsule (ic), the thalamic reticular nucleus (Rt), and the peduncular part of the lateral hypothalamus (PLH) brain regions, as well as the relative positions of these brain structures. The MEAs designed in this study provide a new detection method and tool for functional localization of PD targets and PD pathogenesis at the cellular level.
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Affiliation(s)
- Yuxin Zhu
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luyi Jing
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruilin Hu
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fan Mo
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qianli Jia
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gucheng Yang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaojie Xu
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meiqi Han
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mixia Wang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinxia Cai
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinping Luo
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute,
Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering,
University of Chinese Academy of Sciences, Beijing 100049, China
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Hamada HT, Abe Y, Takata N, Taira M, Tanaka KF, Doya K. Optogenetic activation of dorsal raphe serotonin neurons induces brain-wide activation. Nat Commun 2024; 15:4152. [PMID: 38755120 PMCID: PMC11099070 DOI: 10.1038/s41467-024-48489-6] [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: 08/12/2022] [Accepted: 05/01/2024] [Indexed: 05/18/2024] Open
Abstract
Serotonin is a neuromodulator that affects multiple behavioral and cognitive functions. Nonetheless, how serotonin causes such a variety of effects via brain-wide projections and various receptors remains unclear. Here we measured brain-wide responses to optogenetic stimulation of serotonin neurons in the dorsal raphe nucleus (DRN) of the male mouse brain using functional MRI with an 11.7 T scanner and a cryoprobe. Transient activation of DRN serotonin neurons caused brain-wide activation, including the medial prefrontal cortex, the striatum, and the ventral tegmental area. The same stimulation under anesthesia with isoflurane decreased brain-wide activation, including the hippocampal complex. These brain-wide response patterns can be explained by DRN serotonergic projection topography and serotonin receptor expression profiles, with enhanced weights on 5-HT1 receptors. Together, these results provide insight into the DR serotonergic system, which is consistent with recent discoveries of its functions in adaptive behaviors.
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Affiliation(s)
- Hiro Taiyo Hamada
- Neural Computation Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
- Research & Development Department, Araya Inc, Tokyo, Japan.
| | - Yoshifumi Abe
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Norio Takata
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Masakazu Taira
- Neural Computation Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Kenji Doya
- Neural Computation Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
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Kuo DP, Chen YC, Li YT, Cheng SJ, Hsieh KLC, Kuo PC, Ou CY, Chen CY. Estimating the volume of penumbra in rodents using DTI and stack-based ensemble machine learning framework. Eur Radiol Exp 2024; 8:59. [PMID: 38744784 PMCID: PMC11093947 DOI: 10.1186/s41747-024-00455-z] [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: 12/20/2023] [Accepted: 03/05/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND This study investigates the potential of diffusion tensor imaging (DTI) in identifying penumbral volume (PV) compared to the standard gadolinium-required perfusion-diffusion mismatch (PDM), utilizing a stack-based ensemble machine learning (ML) approach with enhanced explainability. METHODS Sixteen male rats were subjected to middle cerebral artery occlusion. The penumbra was identified using PDM at 30 and 90 min after occlusion. We used 11 DTI-derived metrics and 14 distance-based features to train five voxel-wise ML models. The model predictions were integrated using stack-based ensemble techniques. ML-estimated and PDM-defined PVs were compared to evaluate model performance through volume similarity assessment, the Pearson correlation analysis, and Bland-Altman analysis. Feature importance was determined for explainability. RESULTS In the test rats, the ML-estimated median PV was 106.4 mL (interquartile range 44.6-157.3 mL), whereas the PDM-defined median PV was 102.0 mL (52.1-144.9 mL). These PVs had a volume similarity of 0.88 (0.79-0.96), a Pearson correlation coefficient of 0.93 (p < 0.001), and a Bland-Altman bias of 2.5 mL (2.4% of the mean PDM-defined PV), with 95% limits of agreement ranging from -44.9 to 49.9 mL. Among the features used for PV prediction, the mean diffusivity was the most important feature. CONCLUSIONS Our study confirmed that PV can be estimated using DTI metrics with a stack-based ensemble ML approach, yielding results comparable to the volume defined by the standard PDM. The model explainability enhanced its clinical relevance. Human studies are warranted to validate our findings. RELEVANCE STATEMENT The proposed DTI-based ML model can estimate PV without the need for contrast agent administration, offering a valuable option for patients with kidney dysfunction. It also can serve as an alternative if perfusion map interpretation fails in the clinical setting. KEY POINTS • Penumbral volume can be estimated by DTI combined with stack-based ensemble ML. • Mean diffusivity was the most important feature used for predicting penumbral volume. • The proposed approach can be beneficial for patients with kidney dysfunction.
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Affiliation(s)
- Duen-Pang Kuo
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu Hsing Street, Taipei, Taiwan
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yung-Chieh Chen
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu Hsing Street, Taipei, Taiwan.
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan.
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
| | - Yi-Tien Li
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Research Center for Neuroscience, Taipei Medical University, Taipei, Taiwan
- Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Sho-Jen Cheng
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu Hsing Street, Taipei, Taiwan
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Kevin Li-Chun Hsieh
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu Hsing Street, Taipei, Taiwan
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Po-Chih Kuo
- Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Chen-Yin Ou
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Cheng-Yu Chen
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu Hsing Street, Taipei, Taiwan
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Research Center for Artificial Intelligence in Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Radiology, National Defense Medical Center, Taipei, Taiwan
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Luppi AI, Uhrig L, Tasserie J, Signorelli CM, Stamatakis EA, Destexhe A, Jarraya B, Cofre R. Local orchestration of distributed functional patterns supporting loss and restoration of consciousness in the primate brain. Nat Commun 2024; 15:2171. [PMID: 38462641 PMCID: PMC10925605 DOI: 10.1038/s41467-024-46382-w] [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: 07/16/2023] [Accepted: 02/26/2024] [Indexed: 03/12/2024] Open
Abstract
A central challenge of neuroscience is to elucidate how brain function supports consciousness. Here, we combine the specificity of focal deep brain stimulation with fMRI coverage of the entire cortex, in awake and anaesthetised non-human primates. During propofol, sevoflurane, or ketamine anaesthesia, and subsequent restoration of responsiveness by electrical stimulation of the central thalamus, we investigate how loss of consciousness impacts distributed patterns of structure-function organisation across scales. We report that distributed brain activity under anaesthesia is increasingly constrained by brain structure across scales, coinciding with anaesthetic-induced collapse of multiple dimensions of hierarchical cortical organisation. These distributed signatures are observed across different anaesthetics, and they are reversed by electrical stimulation of the central thalamus, coinciding with recovery of behavioural markers of arousal. No such effects were observed upon stimulating the ventral lateral thalamus, demonstrating specificity. Overall, we identify consistent distributed signatures of consciousness that are orchestrated by specific thalamic nuclei.
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Affiliation(s)
- Andrea I Luppi
- Division of Anaesthesia and Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
| | - Lynn Uhrig
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191, Gif-sur-Yvette, France
- Department of Anesthesiology and Critical Care, Necker Hospital, AP-HP, Université de Paris Cité, Paris, France
| | - Jordy Tasserie
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191, Gif-sur-Yvette, France
- Center for Brain Circuit Therapeutics, Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Camilo M Signorelli
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191, Gif-sur-Yvette, France
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles, 1070, Brussels, Belgium
- Department of Computer Science, University of Oxford, Oxford, 7 Parks Rd, Oxford, OX1 3QG, UK
| | - Emmanuel A Stamatakis
- Division of Anaesthesia and Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Alain Destexhe
- Institute of Neuroscience (NeuroPSI), Paris-Saclay University, Centre National de la Recherche Scientifique (CNRS), Gif-sur-Yvette, France
| | - Bechir Jarraya
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191, Gif-sur-Yvette, France
- Department of Neurology, Hopital Foch, 92150, Suresnes, France
| | - Rodrigo Cofre
- Institute of Neuroscience (NeuroPSI), Paris-Saclay University, Centre National de la Recherche Scientifique (CNRS), Gif-sur-Yvette, France.
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Le Bihan D. From Black Holes Entropy to Consciousness: The Dimensions of the Brain Connectome. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1645. [PMID: 38136525 PMCID: PMC10743094 DOI: 10.3390/e25121645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/28/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023]
Abstract
It has been shown that the theory of relativity can be applied physically to the functioning brain, so that the brain connectome should be considered as a four-dimensional spacetime entity curved by brain activity, just as gravity curves the four-dimensional spacetime of the physical world. Following the most recent developments in modern theoretical physics (black hole entropy, holographic principle, AdS/CFT duality), we conjecture that consciousness can naturally emerge from this four-dimensional brain connectome when a fifth dimension is considered, in the same way that gravity emerges from a 'flat' four-dimensional quantum world, without gravitation, present at the boundaries of a five-dimensional spacetime. This vision makes it possible to envisage quantitative signatures of consciousness based on the entropy of the connectome and the curvature of spacetime estimated from data obtained by fMRI in the resting state (nodal activity and functional connectivity) and constrained by the anatomical connectivity derived from diffusion tensor imaging.
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Affiliation(s)
- Denis Le Bihan
- NeuroSpin, Frédéric Joliot Institute for Life Sciences (Commissariat à l’Energie Atomique, CEA), Centre d’Études de Saclay, Paris-Saclay University, Bâtiment 145, 91191 Gif-sur-Yvette, France;
- Human Brain Research Center, Kyoto University, Kyoto 606-8501, Japan
- Department of System Neuroscience, National Institutes for Physiological Sciences, Okazaki 444-8585, Japan
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11
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Carisch L, Lindt B, Richter H, Del Chicca F. Regional ADC values of the morphologically normal canine brain. Front Vet Sci 2023; 10:1219943. [PMID: 38026624 PMCID: PMC10663295 DOI: 10.3389/fvets.2023.1219943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Diffusion-weighted magnetic resonance imaging is increasingly available for investigation of canine brain diseases. Apparent diffusion coefficient (ADC) of normal canine brains is reported only in small numbers of subjects. The aim of the study was to investigate the ADC of different anatomical regions in the morphologically normal brain in a large population of canine patients in clinical setting. Additionally, possible influence on the ADC value of patient-related factors like sex, age and body weight, difference between the left and right side of the cerebral hemispheres, and between gray and white matter were investigated. Methods Brain magnetic resonance studies including diffusion-weighted images of dogs presented at the Vetsuisse Faculty-University Zurich between 2015 and 2020 were reviewed retrospectively. Only morphologically normal brain magnetic resonance studies of dogs presented with neurological signs or non-neurological signs were included. Apparent diffusion coefficient values of 12 regions of interest (ROIs) in each hemisphere and an additional region in the cerebellar vermis were examined in each dog. Results A total of 321 dogs (including 247 dogs with neurological signs and 62 dogs with non-neurological signs) of various breeds, sex and age were included. Apparent diffusion coefficient significantly varied among most anatomical brain regions. A significantly higher ADC was measured in the gray [median 0.79 (range 0.69-0.90) × 10-3 mm2/s] compared to the white matter [median 0.70 (range 0.63-0.85) × 10-3 mm2/s]. No significant differences were found between the left and right cerebral hemispheres in most of the regions, neither between sexes, different reproductive status, and not consistently between body weight groups. Age was correlated first with a decrease from dogs <1 year of age to middle-age (⩾3 to <8 years) dogs and later with an increase of ADC values in dogs ⩾8 years. Discussion Apparent diffusion coefficient values of 25 ROIs were described in 321 morphologically normal canine brains in clinical setting. Apparent diffusion coefficient differences depending on the brain anatomical region are present. Apparent diffusion coefficient differences among age classes are present, likely consistent with brain maturation and aging. The described data can be a reference for future studies in clinical settings on the canine brain.
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Affiliation(s)
- Lea Carisch
- Clinic for Diagnostic Imaging, Department of Diagnostics and Clinical Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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12
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Wu CY, Hsieh HH, Huang SM, Chiu SC, Peng SL. Brain alterations in ovariohysterectomized rats revealed by diffusion tensor imaging. Neuroreport 2023; 34:649-654. [PMID: 37506310 DOI: 10.1097/wnr.0000000000001937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
OBJECTIVES Women undergoing hysterectomy with oophorectomy have an increased risk of Alzheimer's disease and Parkinson's disease. However, postoperative neuroimaging data on pathogenic processes in the brain are limited. The aim of this study was to investigate the potential effect of ovariohysterectomy on brain integrity in rat model using diffusion tensor imaging (DTI) technique for the first time. METHODS We enrolled 13 rats each in the control and ovariohysterectomy groups. Rats in the ovariohysterectomy group underwent the ovariohysterectomy at 7 weeks of age, and all rats underwent DTI scans at 9 weeks of age. The DTI-derived parameters, such as fractional anisotropy and mean diffusivity, were compared between the control and ovariohysterectomy groups. RESULTS Compared to the control group, the ovariohysterectomy group showed significantly lower fractional anisotropy in various brain regions, including the corpus callosum, bilateral striatum, and bilateral cortex (all P < 0.05), suggesting neuronal injury in ovariohysterectomized rats. Mean diffusivity did not differ significantly between groups (all P > 0.05). CONCLUSION Rats undergoing ovariohysterectomy had lower fractional anisotropy compared to control in widespread brain regions, suggesting neuronal injury and demyelination. Therefore, neuroimaging should be performed to monitor brain alterations in women after hysterectomy with bilateral oophorectomy in clinical settings.
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Affiliation(s)
- Chun-Yi Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei Branch, Taipei
| | - Hsin-Hua Hsieh
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei Branch, Taipei
| | - Sheng-Min Huang
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli
| | - Shao-Chieh Chiu
- Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science
- Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan
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13
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Peng SL, Huang SM, Chu LWL, Chiu SC. Anesthetic modulation of water diffusion: Insights from a diffusion tensor imaging study. Med Eng Phys 2023; 118:104015. [PMID: 37536836 DOI: 10.1016/j.medengphy.2023.104015] [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] [Received: 11/25/2022] [Revised: 06/15/2023] [Accepted: 06/24/2023] [Indexed: 08/05/2023]
Abstract
Diffusion tensor imaging (DTI) in animal models are essential for translational neuroscience studies. A critical step in animal studies is the use of anesthetics. Understanding the influence of specific anesthesia regimes on DTI-derived parameters, such as fractional anisotropy (FA) and mean diffusivity (MD), is imperative when comparing results between animal studies using different anesthetics. Here, the quantification of FA and MD under different anesthetic regimes, alpha-chloralose and isoflurane, is discussed. We also used a range of b-values to determine whether the anesthetic effect was b-value dependent. The first group of rats (n = 6) was anesthetized with alpha-chloralose (80 mg/kg), whereas the second group of rats (n = 7) was anesthetized with isoflurane (1.5%). DTI was performed with b-values of 500, 1500, and 1500s/mm2, and the MD and FA were assessed individually. Anesthesia-specific differences in MD were apparent, as manifested by the higher estimated MD under isoflurane anesthesia than that under alpha-chloralose anesthesia (P < 0.001). MD values increased with decreasing b-value in all regions studied, and the degree of increase when rats were anesthetized with isoflurane was more pronounced than that associated with alpha-chloralose (P < 0.05). FA quantitation was also influenced by anesthesia regimens to varying extents, depending on the brain regions and b-values. In conclusion, both scanning parameters and the anesthesia regimens significantly impacted the quantification of DTI indices.
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Affiliation(s)
- Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan; Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan.
| | - Sheng-Min Huang
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan
| | - Lok Wang Lauren Chu
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
| | - Shao-Chieh Chiu
- Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan, Taiwan
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14
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Segeroth M, Wachsmuth L, Gagel M, Albers F, Hess A, Faber C. Disentangling the impact of cerebrospinal fluid formation and neuronal activity on solute clearance from the brain. Fluids Barriers CNS 2023; 20:43. [PMID: 37316849 DOI: 10.1186/s12987-023-00443-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/18/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Despite recent attention, pathways and mechanisms of fluid transposition in the brain are still a matter of intense discussion and driving forces underlying waste clearance in the brain remain elusive. Consensus exists that net solute transport is a prerequisite for efficient clearance. The individual impact of neuronal activity and cerebrospinal fluid (CSF) formation, which both vary with brain state and anesthesia, remain unclear. METHODS To separate conditions with high and low neuronal activity and high and low CSF formation, different anesthetic regimens in naive rat were established, using Isoflurane (ISO), Medetomidine (MED), acetazolamide or combinations thereof. With dynamic contrast-enhanced MRI, after application of low molecular weight contrast agent (CA) Gadobutrol to cisterna magna, tracer distribution was monitored as surrogate for solute clearance. Simultaneous fiber-based Ca2+-recordings informed about the state of neuronal activity under different anesthetic regimen. T2-weighted MRI and diffusion-weighted MRI (DWI) provided size of subarachnoidal space and aqueductal flow as surrogates for CSF formation. Finally, a pathway and mechanism-independent two-compartment model was introduced to provide a measure of efficiency for solute clearance from the brain. RESULTS Anatomical imaging, DWI and Ca2+-recordings confirmed that conditions with distinct levels of neuronal activity and CSF formation were achieved. A sleep-resembling condition, with reduced neuronal activity and enhanced CSF formation was achieved using ISO+MED and an awake-like condition with high neuronal activity using MED alone. CA distribution in the brain correlated with the rate of CSF formation. The cortical brain state had major influence on tracer diffusion. Under conditions with low neuronal activity, higher diffusivity suggested enlargement of extracellular space, facilitating a deeper permeation of solutes into brain parenchyma. Under conditions with high neuronal activity, diffusion of solutes into parenchyma was hindered and clearance along paravascular pathways facilitated. Exclusively based on the measured time signal curves, the two-compartment model provided net exchange ratios, which were significantly larger for the sleep-resembling condition than for the awake-like condition. CONCLUSIONS Efficiency of solute clearance in brain changes with alterations in both state of neuronal activity and CSF formation. Our clearance pathway and mechanism agnostic kinetic model informs about net solute transport, solely based on the measured time signal curves. This rather simplifying approach largely accords with preclinical and clinical findings.
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Affiliation(s)
- Martin Segeroth
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
- Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Lydia Wachsmuth
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Mathias Gagel
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Franziska Albers
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Andreas Hess
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
- Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
- FAU NeW, Research Center for New Bioactive Compounds, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Cornelius Faber
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany.
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15
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Guadilla I, González S, Cerdán S, Lizarbe B, López-Larrubia P. Magnetic resonance imaging to assess the brain response to fasting in glioblastoma-bearing rats as a model of cancer anorexia. Cancer Imaging 2023; 23:36. [PMID: 37038232 PMCID: PMC10088192 DOI: 10.1186/s40644-023-00553-y] [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: 11/15/2022] [Accepted: 04/03/2023] [Indexed: 04/12/2023] Open
Abstract
BACKGROUND Global energy balance is a vital process tightly regulated by the brain that frequently becomes dysregulated during the development of cancer. Glioblastoma (GBM) is one of the most investigated malignancies, but its appetite-related disorders, like anorexia/cachexia symptoms, remain poorly understood. METHODS We performed manganese enhanced magnetic resonance imaging (MEMRI) and subsequent diffusion tensor imaging (DTI), in adult male GBM-bearing (n = 13) or control Wistar rats (n = 12). A generalized linear model approach was used to assess the effects of fasting in different brain regions involved in the regulation of the global energy metabolism: cortex, hippocampus, hypothalamus and thalamus. The regions were selected on the contralateral side in tumor-bearing animals, and on the left hemisphere in control rats. An additional DTI-only experiment was completed in two additional GBM (n = 5) or healthy cohorts (n = 6) to assess the effects of manganese infusion on diffusion measurements. RESULTS MEMRI results showed lower T1 values in the cortex (p-value < 0.001) and thalamus (p-value < 0.05) of the fed ad libitum GBM animals, as compared to the control cohort, consistent with increased Mn2+ accumulation. No MEMRI-detectable differences were reported between fed or fasting rats, either in control or in the GBM group. In the MnCl2-infused cohorts, DTI studies showed no mean diffusivity (MD) variations from the fed to the fasted state in any animal cohort. However, the DTI-only set of acquisitions yielded remarkably decreased MD values after fasting only in the healthy control rats (p-value < 0.001), and in all regions, but thalamus, of GBM compared to control animals in the fed state (p-value < 0.01). Fractional anisotropy (FA) decreased in tumor-bearing rats due to the infiltrate nature of the tumor, which was detected in both diffusion sets, with (p-value < 0.01) and without Mn2+ administration (p-value < 0.001). CONCLUSIONS Our results revealed that an altered physiological brain response to fasting occurred in hunger related regions in GBM animals, detectable with DTI, but not with MEMRI acquisitions. Furthermore, the present results showed that Mn2+ induces neurotoxic inflammation, which interferes with diffusion MRI to detect appetite-induced responses through MD changes.
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Affiliation(s)
- Irene Guadilla
- Biomedical Magnetic Resonance Group, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, C/ Arturo Duperier 4, 28029, Madrid, Spain
| | - Sara González
- Biomedical Magnetic Resonance Group, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, C/ Arturo Duperier 4, 28029, Madrid, Spain
| | - Sebastián Cerdán
- Biomedical Magnetic Resonance Group, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, C/ Arturo Duperier 4, 28029, Madrid, Spain
| | - Blanca Lizarbe
- Biomedical Magnetic Resonance Group, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, C/ Arturo Duperier 4, 28029, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, 28029, Madrid, Spain
| | - Pilar López-Larrubia
- Biomedical Magnetic Resonance Group, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, C/ Arturo Duperier 4, 28029, Madrid, Spain.
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16
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Springer CS, Baker EM, Li X, Moloney B, Wilson GJ, Pike MM, Barbara TM, Rooney WD, Maki JH. Metabolic activity diffusion imaging (MADI): I. Metabolic, cytometric modeling and simulations. NMR IN BIOMEDICINE 2023; 36:e4781. [PMID: 35654608 DOI: 10.1002/nbm.4781] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Evidence mounts that the steady-state cellular water efflux (unidirectional) first-order rate constant (kio [s-1 ]) magnitude reflects the ongoing, cellular metabolic rate of the cytolemmal Na+ , K+ -ATPase (NKA), c MRNKA (pmol [ATP consumed by NKA]/s/cell), perhaps biology's most vital enzyme. Optimal 1 H2 O MR kio determinations require paramagnetic contrast agents (CAs) in model systems. However, results suggest that the homeostatic metabolic kio biomarker magnitude in vivo is often too large to be reached with allowable or possible CA living tissue distributions. Thus, we seek a noninvasive (CA-free) method to determine kio in vivo. Because membrane water permeability has long been considered important in tissue water diffusion, we turn to the well-known diffusion-weighted MRI (DWI) modality. To analyze the diffusion tensor magnitude, we use a parsimoniously primitive model featuring Monte Carlo simulations of water diffusion in virtual ensembles comprising water-filled and -immersed randomly sized/shaped contracted Voronoi cells. We find this requires two additional, cytometric properties: the mean cell volume (V [pL]) and the cell number density (ρ [cells/μL]), important biomarkers in their own right. We call this approach metabolic activity diffusion imaging (MADI). We simulate water molecule displacements and transverse MR signal decays covering the entirety of b-space from pure water (ρ = V = 0; kio undefined; diffusion coefficient, D0 ) to zero diffusion. The MADI model confirms that, in compartmented spaces with semipermeable boundaries, diffusion cannot be described as Gaussian: the nanoscopic D (Dn ) is diffusion time-dependent, a manifestation of the "diffusion dispersion". When the "well-mixed" (steady-state) condition is reached, diffusion becomes limited, mainly by the probabilities of (1) encountering (ρ, V), and (2) permeating (kio ) cytoplasmic membranes, and less so by Dn magnitudes. Importantly, for spaces with large area/volume (A/V; claustrophobia) ratios, this can happen in less than a millisecond. The model matches literature experimental data well, with implications for DWI interpretations.
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Affiliation(s)
- Charles S Springer
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
- Brenden-Colson Center for Pancreatic Care, Oregon Health & Science University, Portland, Oregon, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon, USA
| | - Eric M Baker
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
| | - Xin Li
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
- Brenden-Colson Center for Pancreatic Care, Oregon Health & Science University, Portland, Oregon, USA
| | - Brendan Moloney
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
| | - Gregory J Wilson
- Department of Radiology, University of Washington, Seattle, Washington, USA
- Bayer Healthcare, Radiology, New Jersey, USA
| | - Martin M Pike
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
| | - Thomas M Barbara
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
| | - William D Rooney
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA
| | - Jeffrey H Maki
- Anschutz Medical Center Department of Radiology, University of Colorado, Aurora, Colorado, USA
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Han Z, Han Y, Huang X, Ma H, Zhang X, Song J, Dong J, Li S, Yu R, Liu H. A Novel Targeted Nanoparticle for Traumatic Brain Injury Treatment: Combined Effect of ROS Depletion and Calcium Overload Inhibition. Adv Healthc Mater 2022; 11:e2102256. [PMID: 35118827 DOI: 10.1002/adhm.202102256] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/25/2021] [Indexed: 12/11/2022]
Abstract
Survival after severe traumatic brain injury (TBI) depends on minimizing or avoiding secondary insults to the brain. Overproduction of reactive oxygen species (ROS) and Ca2+ influx at the damaged site are the key factors that cause secondary injury upon TBI. Herein, a TBI-targeted lipid covered radical scavenger nanoparticle is developed to deliver nimodipine (Np) (CL-PPS/Np), in order to inhibit Ca2+ influx in neurons by Np and to scavenge ROS in the brain trauma microenvironment by poly(propylene sulfide)60 (PPS60 ) and thus prevent TBI-associated secondary injury. In post-TBI models, CL-PPS/Np effectively accumulates into the wound cavity and prolongs the time of systemic circulation of Np. CL-PPS/Np can markedly protect the integrity of blood-brain barrier, prevent brain edema, reduce cell death and inflammatory responses, and promote functional recovery after TBI. These findings may provide a new therapy for TBI to prevent the spread of the secondary injury.
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Affiliation(s)
- Zhengzhong Han
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
- Department of Biomedical Engineering Southern University of Science and Technology Shenzhen Guangdong 518055 P. R. China
| | - Yuhan Han
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Xuyang Huang
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
- Department of Neurosurgery Affiliated Hospital of Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Hongwei Ma
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Xuefeng Zhang
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Jingyuan Song
- School of Nursing Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Jun Dong
- Department of Neurosurgery the Second Affiliated Hospital of Suzhou University Suzhou 215000 China
| | - Shanshan Li
- Jiangsu Medical Engineering Research Center of Gene Detection and Department of Forensic Medicine Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Rutong Yu
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
- Department of Neurosurgery Affiliated Hospital of Xuzhou Medical University Xuzhou 221002 P. R. China
| | - Hongmei Liu
- Institute of Nervous System Diseases Xuzhou Medical University Xuzhou 221002 P. R. China
- Department of Biomedical Engineering Southern University of Science and Technology Shenzhen Guangdong 518055 P. R. China
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Tasserie J, Uhrig L, Sitt JD, Manasova D, Dupont M, Dehaene S, Jarraya B. Deep brain stimulation of the thalamus restores signatures of consciousness in a nonhuman primate model. SCIENCE ADVANCES 2022; 8:eabl5547. [PMID: 35302854 PMCID: PMC8932660 DOI: 10.1126/sciadv.abl5547] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 01/26/2022] [Indexed: 05/27/2023]
Abstract
Loss of consciousness is associated with the disruption of long-range thalamocortical and corticocortical brain communication. We tested the hypothesis that deep brain stimulation (DBS) of central thalamus might restore both arousal and awareness following consciousness loss. We applied anesthesia to suppress consciousness in nonhuman primates. During anesthesia, central thalamic stimulation induced arousal in an on-off manner and increased functional magnetic resonance imaging activity in prefrontal, parietal, and cingulate cortices. Moreover, DBS restored a broad dynamic repertoire of spontaneous resting-state activity, previously described as a signature of consciousness. None of these effects were obtained during the stimulation of a control site in the ventrolateral thalamus. Last, DBS restored a broad hierarchical response to auditory violations that was disrupted under anesthesia. Thus, DBS restored the two dimensions of consciousness, arousal and conscious access, following consciousness loss, paving the way to its therapeutical translation in patients with disorders of consciousness.
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Affiliation(s)
- Jordy Tasserie
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France
| | - Lynn Uhrig
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France
- Department of Anesthesiology and Critical Care, Necker Hospital, AP-HP, Université de Paris, Paris, France
| | - Jacobo D. Sitt
- Sorbonne Université, Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Dragana Manasova
- Sorbonne Université, Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
- Université de Paris, Paris, France
| | - Morgan Dupont
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France
| | - Stanislas Dehaene
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France
- Collège de France, Université Paris-Sciences-Lettres (PSL), Paris, France
| | - Béchir Jarraya
- Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France
- University of Versailles Saint-Quentin-en-Yvelines, Université Paris-Saclay, Versailles, France
- Foch Hospital, Suresnes, France
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19
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Porat S, Sibilia F, Yoon J, Shi Y, Dahl MJ, Werkle-Bergner M, Düzel S, Bodammer N, Lindenberger U, Kühn S, Mather M. Age Differences in Diffusivity in the Locus Coeruleus and its Ascending Noradrenergic Tract. Neuroimage 2022; 251:119022. [PMID: 35192943 PMCID: PMC9183949 DOI: 10.1016/j.neuroimage.2022.119022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 12/11/2022] Open
Abstract
The noradrenergic locus coeruleus (LC) is a small brainstem nucleus that promotes arousal and attention. Recent studies have examined the microstructural properties of the LC using diffusion-weighted magnetic resonance imaging and found unexpected age-related differences in fractional anisotropy - a measure of white matter integrity. Here, we used two datasets (Berlin Aging Study-II, N = 301, the Leipzig Study for Mind-Body-Emotion Interactions, N = 220), to replicate published findings and expand them by investigating diffusivity in the LC’s ascending noradrenergic bundle. In younger adults, LC fractional anisotropy was significantly lower, compared to older adults. However, in the LC’s ascending noradrenergic bundle, we observed significantly higher fractional anisotropy in younger adults, relative to older adults. These findings indicate that diffusivity in the LC versus the ascending noradrenergic bundle are both susceptible to structural changes in aging that have opposing effects on fractional anisotropy.
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20
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Figley CR, Uddin MN, Wong K, Kornelsen J, Puig J, Figley TD. Potential Pitfalls of Using Fractional Anisotropy, Axial Diffusivity, and Radial Diffusivity as Biomarkers of Cerebral White Matter Microstructure. Front Neurosci 2022; 15:799576. [PMID: 35095400 PMCID: PMC8795606 DOI: 10.3389/fnins.2021.799576] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/17/2021] [Indexed: 01/31/2023] Open
Abstract
Fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) are commonly used as MRI biomarkers of white matter microstructure in diffusion MRI studies of neurodevelopment, brain aging, and neurologic injury/disease. Some of the more frequent practices include performing voxel-wise or region-based analyses of these measures to cross-sectionally compare individuals or groups, longitudinally assess individuals or groups, and/or correlate with demographic, behavioral or clinical variables. However, it is now widely recognized that the majority of cerebral white matter voxels contain multiple fiber populations with different trajectories, which renders these metrics highly sensitive to the relative volume fractions of the various fiber populations, the microstructural integrity of each constituent fiber population, and the interaction between these factors. Many diffusion imaging experts are aware of these limitations and now generally avoid using FA, AD or RD (at least in isolation) to draw strong reverse inferences about white matter microstructure, but based on the continued application and interpretation of these metrics in the broader biomedical/neuroscience literature, it appears that this has perhaps not yet become common knowledge among diffusion imaging end-users. Therefore, this paper will briefly discuss the complex biophysical underpinnings of these measures in the context of crossing fibers, provide some intuitive “thought experiments” to highlight how conventional interpretations can lead to incorrect conclusions, and suggest that future studies refrain from using (over-interpreting) FA, AD, and RD values as standalone biomarkers of cerebral white matter microstructure.
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Affiliation(s)
- Chase R. Figley
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
- Division of Diagnostic Imaging, Health Sciences Centre, Winnipeg, MB, Canada
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg, MB, Canada
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
- *Correspondence: Chase R. Figley,
| | - Md Nasir Uddin
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
- Department of Neurology, University of Rochester, Rochester, NY, United States
| | - Kaihim Wong
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg, MB, Canada
| | - Jennifer Kornelsen
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
- Division of Diagnostic Imaging, Health Sciences Centre, Winnipeg, MB, Canada
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg, MB, Canada
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Josep Puig
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
- Division of Diagnostic Imaging, Health Sciences Centre, Winnipeg, MB, Canada
- Girona Biomedical Research Institute (IDIBGI), Hospital Universitari de Girona Dr. Josep Trueta, Girona, Spain
| | - Teresa D. Figley
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
- Division of Diagnostic Imaging, Health Sciences Centre, Winnipeg, MB, Canada
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg, MB, Canada
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
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21
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Arboit A, Ku SP, Krautwald K, Angenstein F. Brief neuronal afterdischarges in the rat hippocampus lead to transient changes in oscillatory activity and to a very long-lasting decline in BOLD signals without inducing a hypoxic state. Neuroimage 2021; 245:118769. [PMID: 34861394 DOI: 10.1016/j.neuroimage.2021.118769] [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: 09/22/2021] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022] Open
Abstract
The effects of hippocampal neuronal afterdischarges (nAD) on hemodynamic parameters, such as blood-oxygen-level-dependent (BOLD) signals) and local cerebral blood volume (CBV) changes, as well as neuronal activity and metabolic parameters in the dentate gyrus, was investigated in rats by combining in vivo electrophysiology with functional magnetic resonance imaging (fMRI) or 1H-nuclear magnetic resonance spectroscopy (1H-NMRS). Brief electrical high-frequency pulse-burst stimulation of the right perforant pathway triggered nAD, a seizure-like activity, in the right dentate gyrus with a high incidence, a phenomenon that in turn caused a sustained decrease in BOLD signals for more than 30 min. The decrease was associated with a reduction in CBV but not with signs of hypoxic metabolism. nAD also triggered transient changes mainly in the low gamma frequency band that recovered within 20 min, so that the longer-lasting altered hemodynamics reflected a switch in blood supply rather than transient changes in ongoing neuronal activity. Even in the presence of reduced baseline BOLD signals, neurovascular coupling mechanisms remained intact, making long-lasting vasospasm unlikely. Subsequently generated nAD did not further alter the baseline BOLD signals. Similarly, nAD did not alter baseline BOLD signals when acetaminophen was previously administered, because acetaminophen alone had already caused a similar decrease in baseline BOLD signals as observed after the first nAD. Thus, at least two different blood supply states exist for the hippocampus, one low and one high, with both states allowing similar neuronal activity. Both acetaminophen and nAD switch from the high to the low blood supply state. As a result, the hemodynamic response function to an identical stimulus differed after nAD or acetaminophen, although the triggered neuronal activity was similar.
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Affiliation(s)
- Alberto Arboit
- Functional Neuroimaging Group, Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Leipzigerstr, 44, Magdeburg 39118, Germany
| | - Shih-Pi Ku
- Department Functional Architecture of Memory, Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Karla Krautwald
- Functional Neuroimaging Group, Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Leipzigerstr, 44, Magdeburg 39118, Germany
| | - Frank Angenstein
- Functional Neuroimaging Group, Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Leipzigerstr, 44, Magdeburg 39118, Germany; Department Functional Architecture of Memory, Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; Center for Behavior and Brain Sciences (CBBS), Magdeburg, Germany; Medical Faculty, Otto von Guericke University, Magdeburg 39118, Germany.
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22
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Tanaka K. Astroglia and Obsessive Compulsive Disorder. ADVANCES IN NEUROBIOLOGY 2021; 26:139-149. [PMID: 34888834 DOI: 10.1007/978-3-030-77375-5_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Obsessive compulsive disorder (OCD) has a prevalence rate of 1-3% in the general population and has been ranked as one of the top ten leading causes of illness-related disability (American Psychiatric Association 2013; Kessler et al. 2005). OCD is characterized by persistent intrusive thoughts (obsessions) and repetitive behaviors (compulsions) (Leckman et al. 1997). There are various OCD-related disorders, including Tourette syndrome (TS), grooming disorders (e.g., skin-picking, trichotillomania), and autism spectrum disorders (ASD) that share considerable overlapping features with OCD (Browne et al. 2014). Although the neurobiological basis of OCD still remains obscure, neuroimaging studies in patients with OCD and OCD-related disorders have consistently identified hyperactivity in orbitofrontal cortex and striatum (Cerliani et al. 2015; Hou et al. 2014; Jung et al. 2017; Neuner et al. 2014). However, the cellular and synaptic abnormalities underlying this hyperactivity are unclear. The most prominent theory regarding the underlying mechanisms of OCD and OCD-related disorders is an increased excitation to inhibition (E/I) ratio due to increased glutamatergic excitation or reduced GABAergic inhibition (Albin and Mink 2006; Rubenstein and Merzenich 2003; Wu et al. 2012). A proper E/I ratio is achieved by factors expressed in neuron and glia. In astrocytes, both the glutamate transporter GLT1 and GABA transporter GAT-3 are critical for regulating the E/I balance (Aida et al. 2015; Aizawa et al. 2020; Boddum et al. 2016; Cui et al. 2014; Kersanté et al. 2013; Kiryk et al. 2008; Matos et al. 2018; Scimemi 2014; Sugimoto et al. 2018; Sugiyama et al. 2017; Tanaka et al. 1997; Zhao et al. 2018). Although astrocyte dysfunction has not been directly explored in OCD patients, several animal studies have found that astrocytes are involved in the pathophysiology of OCD. In this chapter, I highlight recent studies in which astrocyte dysfunction contributed to E/I imbalance, leading to pathological repetitive behaviors shared between patients with OCD, TS, and ASD.
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Affiliation(s)
- Kohichi Tanaka
- Tokyo Medical and Dental University, Department of Molecular Neuroscience, Medical Research Institute, Tokyo, Japan.
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23
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Markicevic M, Savvateev I, Grimm C, Zerbi V. Emerging imaging methods to study whole-brain function in rodent models. Transl Psychiatry 2021; 11:457. [PMID: 34482367 PMCID: PMC8418612 DOI: 10.1038/s41398-021-01575-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/05/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023] Open
Abstract
In the past decade, the idea that single populations of neurons support cognition and behavior has gradually given way to the realization that connectivity matters and that complex behavior results from interactions between remote yet anatomically connected areas that form specialized networks. In parallel, innovation in brain imaging techniques has led to the availability of a broad set of imaging tools to characterize the functional organization of complex networks. However, each of these tools poses significant technical challenges and faces limitations, which require careful consideration of their underlying anatomical, physiological, and physical specificity. In this review, we focus on emerging methods for measuring spontaneous or evoked activity in the brain. We discuss methods that can measure large-scale brain activity (directly or indirectly) with a relatively high temporal resolution, from milliseconds to seconds. We further focus on methods designed for studying the mammalian brain in preclinical models, specifically in mice and rats. This field has seen a great deal of innovation in recent years, facilitated by concomitant innovation in gene-editing techniques and the possibility of more invasive recordings. This review aims to give an overview of currently available preclinical imaging methods and an outlook on future developments. This information is suitable for educational purposes and for assisting scientists in choosing the appropriate method for their own research question.
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Affiliation(s)
- Marija Markicevic
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
| | - Iurii Savvateev
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
- Decision Neuroscience Lab, HEST, ETH Zürich, Zürich, Switzerland
| | - Christina Grimm
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
| | - Valerio Zerbi
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland.
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland.
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24
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Abe Y, Kwon S, Oishi M, Unekawa M, Takata N, Seki F, Koyama R, Abe M, Sakimura K, Masamoto K, Tomita Y, Okano H, Mushiake H, Tanaka KF. Optical manipulation of local cerebral blood flow in the deep brain of freely moving mice. Cell Rep 2021; 36:109427. [PMID: 34320360 DOI: 10.1016/j.celrep.2021.109427] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/07/2021] [Accepted: 06/29/2021] [Indexed: 11/18/2022] Open
Abstract
An artificial tool for manipulating local cerebral blood flow (CBF) is necessary for understanding how CBF controls brain function. Here, we generate vascular optogenetic tools whereby smooth muscle cells and endothelial cells express optical actuators in the brain. The illumination of channelrhodopsin-2 (ChR2)-expressing mice induces a local reduction in CBF. Photoactivated adenylyl cyclase (PAC) is an optical protein that increases intracellular cyclic adenosine monophosphate (cAMP), and the illumination of PAC-expressing mice induces a local increase in CBF. We target the ventral striatum, determine the temporal kinetics of CBF change, and optimize the illumination intensity to confine the effects to the ventral striatum. We demonstrate the utility of this vascular optogenetic manipulation in freely and adaptively behaving mice and validate the task- and actuator-dependent behavioral readouts. The development of vascular optogenetic animal models will help accelerate research linking vasculature, circuits, and behavior to health and disease.
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Affiliation(s)
- Yoshifumi Abe
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan; Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan
| | - Soojin Kwon
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan; Department of Physiology, Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Mitsuhiro Oishi
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Miyuki Unekawa
- Department of Neurology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Norio Takata
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan; Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan
| | - Fumiko Seki
- Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan; Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Kazuto Masamoto
- Brain Science Inspired Life Support Research Center, University of Electro-Communications, Tokyo 182-8585, Japan
| | - Yutaka Tomita
- Department of Neurology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan; Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Saitama 351-0198, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan.
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25
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Impact of anesthesia on static and dynamic functional connectivity in mice. Neuroimage 2021; 241:118413. [PMID: 34293463 DOI: 10.1016/j.neuroimage.2021.118413] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/13/2021] [Accepted: 07/19/2021] [Indexed: 11/22/2022] Open
Abstract
A few studies have compared the static functional connectivity between awake and lightly anesthetized states in rodents by resting-state fMRI. However, impact of light anesthesia on static and dynamic fluctuations in functional connectivity has not been fully understood. Here, we developed a resting-state fMRI protocol to perform awake and anesthetized functional MRI in the same mice. Static functional connectivity showed a widespread decrease under light anesthesia, such as when under isoflurane or a mixture of isoflurane and medetomidine. Several interhemispheric and subcortical connections were key connections for anesthetized condition from awake state. Dynamic functional connectivity demonstrates the shift from frequent broad connections across the cortex, the hypothalamus, and the auditory-visual cortex to frequent local connections within the cortex only under light anesthesia compared with awake state. Fractional amplitude of low frequency fluctuation in the thalamic nuclei decreased under both anesthesia. These results indicate that typical anesthetics for functional MRI alters the spatiotemporal profile of the dynamic brain network in subcortical regions, including the thalamic nuclei and limbic system.
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26
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Ferris CF. Rethinking the Conditions and Mechanism for Glymphatic Clearance. Front Neurosci 2021; 15:624690. [PMID: 33897347 PMCID: PMC8060639 DOI: 10.3389/fnins.2021.624690] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 03/10/2021] [Indexed: 11/13/2022] Open
Abstract
Critical studies that form the foundation of the glymphatic system and the clearance of metabolic by-products of unwanted proteins from the brain are reviewed. Concerns are raised about studying glymphatic flow in anesthetized animals and making assumptions about the whole brain based upon data collected from a cranial window on the cortex. A new model is proposed arguing that the flow of cerebral spinal fluid and parenchymal clearance in the perivascular system of unwanted proteins is regulated by circadian changes in brain temperature and blood flow at the level of the microvasculature.
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Affiliation(s)
- Craig F Ferris
- Department Psychology and Pharmaceutical Sciences, Center for Translational Neuroimaging, Northeastern University, Boston, MA, United States
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27
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Sorrenti V, Cecchetto C, Maschietto M, Fortinguerra S, Buriani A, Vassanelli S. Understanding the Effects of Anesthesia on Cortical Electrophysiological Recordings: A Scoping Review. Int J Mol Sci 2021; 22:1286. [PMID: 33525470 PMCID: PMC7865872 DOI: 10.3390/ijms22031286] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/21/2021] [Accepted: 01/25/2021] [Indexed: 12/28/2022] Open
Abstract
General anesthesia in animal experiments is an ethical must and is required for all the procedures that are likely to cause more than slight or momentary pain. As anesthetics are known to deeply affect experimental findings, including electrophysiological recordings of brain activity, understanding their mechanism of action is of paramount importance. It is widely recognized that the depth and type of anesthesia introduce significant bias in electrophysiological measurements by affecting the shape of both spontaneous and evoked signals, e.g., modifying their latency and relative amplitude. Therefore, for a given experimental protocol, it is relevant to identify the appropriate anesthetic, to minimize the impact on neuronal circuits and related signals under investigation. This review focuses on the effect of different anesthetics on cortical electrical recordings, examining their molecular mechanisms of action, their influence on neuronal microcircuits and, consequently, their impact on cortical measurements.
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Affiliation(s)
- Vincenzo Sorrenti
- Department of Pharmaceutical & Pharmacological Sciences, University of Padova, 35131 Padova, Italy
- Maria Paola Belloni Center for Personalized Medicine, Data Medica Group (Synlab Limited), 35100 Padova, Italy;
| | - Claudia Cecchetto
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan;
- Department of Biomedical Sciences, Section of Physiology, University of Padova, via F. Marzolo 3, 35131 Padova, Italy;
- Padua Neuroscience Center, University of Padova, via Orus 2/B, 35131 Padova, Italy
| | - Marta Maschietto
- Department of Biomedical Sciences, Section of Physiology, University of Padova, via F. Marzolo 3, 35131 Padova, Italy;
| | | | - Alessandro Buriani
- Maria Paola Belloni Center for Personalized Medicine, Data Medica Group (Synlab Limited), 35100 Padova, Italy;
| | - Stefano Vassanelli
- Department of Biomedical Sciences, Section of Physiology, University of Padova, via F. Marzolo 3, 35131 Padova, Italy;
- Padua Neuroscience Center, University of Padova, via Orus 2/B, 35131 Padova, Italy
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28
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Steiner AR, Rousseau-Blass F, Schroeter A, Hartnack S, Bettschart-Wolfensberger R. Systematic Review: Anesthetic Protocols and Management as Confounders in Rodent Blood Oxygen Level Dependent Functional Magnetic Resonance Imaging (BOLD fMRI)-Part B: Effects of Anesthetic Agents, Doses and Timing. Animals (Basel) 2021; 11:ani11010199. [PMID: 33467584 PMCID: PMC7830239 DOI: 10.3390/ani11010199] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary To understand brain function in rats and mice functional magnetic resonance imaging of the brain is used. With this type of “brain scan” regional changes in blood flow and oxygen consumption are measured as an indirect surrogate for activity of brain regions. Animals are often anesthetized for the experiments to prevent stress and blurred images due to movement. However, anesthesia may alter the measurements, as blood flow within the brain is differently affected by different anesthetics, and anesthetics also directly affect brain function. Consequently, results obtained under one anesthetic protocol may not be comparable with those obtained under another, and/or not representative for awake animals and humans. We have systematically searched the existing literature for studies analyzing the effects of different anesthesia methods or studies that compared anesthetized and awake animals. Most studies reported that anesthetic agents, doses and timing had an effect on functional magnetic resonance imaging results. To obtain results which promote our understanding of brain function, it is therefore essential that a standard for anesthetic protocols for functional magnetic resonance is defined and their impact is well characterized. Abstract In rodent models the use of functional magnetic resonance imaging (fMRI) under anesthesia is common. The anesthetic protocol might influence fMRI readouts either directly or via changes in physiological parameters. As long as those factors cannot be objectively quantified, the scientific validity of fMRI in rodents is impaired. In the present systematic review, literature analyzing in rats and mice the influence of anesthesia regimes and concurrent physiological functions on blood oxygen level dependent (BOLD) fMRI results was investigated. Studies from four databases that were searched were selected following pre-defined criteria. Two separate articles publish the results; the herewith presented article includes the analyses of 83 studies. Most studies found differences in BOLD fMRI readouts with different anesthesia drugs and dose rates, time points of imaging or when awake status was compared to anesthetized animals. To obtain scientifically valid, reproducible results from rodent fMRI studies, stable levels of anesthesia with agents suitable for the model under investigation as well as known and objectively quantifiable effects on readouts are, thus, mandatory. Further studies should establish dose ranges for standardized anesthetic protocols and determine time windows for imaging during which influence of anesthesia on readout is objectively quantifiable.
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Affiliation(s)
- Aline R. Steiner
- Section of Anaesthesiology, Department of Clinical and Diagnostic Services, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
- Correspondence:
| | - Frédérik Rousseau-Blass
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada;
| | - Aileen Schroeter
- Institute for Biomedical Engineering, University and ETH Zurich, 8093 Zurich, Switzerland;
| | - Sonja Hartnack
- Section of Epidemiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
| | - Regula Bettschart-Wolfensberger
- Section of Anaesthesiology, Department of Clinical and Diagnostic Services, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
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29
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Li Y, Han H, Shi K, Cui D, Yang J, Alberts IL, Yuan L, Zhao G, Wang R, Cai X, Teng Z. The Mechanism of Downregulated Interstitial Fluid Drainage Following Neuronal Excitation. Aging Dis 2020; 11:1407-1422. [PMID: 33269097 PMCID: PMC7673848 DOI: 10.14336/ad.2020.0224] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
The drainage of brain interstitial fluid (ISF) has been observed to slow down following neuronal excitation, although the mechanism underlying this phenomenon is yet to be elucidated. In searching for the changes in the brain extracellular space (ECS) induced by electrical pain stimuli in the rat thalamus, significantly decreased effective diffusion coefficient (DECS) and volume fraction (α) of the brain ECS were shown, accompanied by the slowdown of ISF drainage. The morphological basis for structural changes in the brain ECS was local spatial deformation of astrocyte foot processes following neuronal excitation. We further studied aquaporin-4 gene (APQ4) knockout rats in which the changes of the brain ECS structure were reversed and found that the slowed DECS and ISF drainage persisted, confirming that the down-regulation of ISF drainage following neuronal excitation was mainly attributable to the release of neurotransmitters rather than to structural changes of the brain ECS. Meanwhile, the dynamic changes in the DECS were synchronized with the release and elimination processes of neurotransmitters following neuronal excitation. In conclusion, the downregulation of ISF drainage following neuronal excitation was found to be caused by the restricted diffusion in the brain ECS, and DECS mapping may be used to track the neuronal activity in the deep brain.
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Affiliation(s)
- Yuanyuan Li
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Hongbin Han
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China.
| | - Kuangyu Shi
- Department of Nuclear Medicine, University of Bern, 3010 Bern, Switzerland.
- Department of Informatics, Technical University of Munich, Garching 85748, Germany.
| | - Dehua Cui
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Jun Yang
- Department of Radiology, Peking University Third Hospital, Beijing, China.
| | - Ian Leigh Alberts
- Department of Nuclear Medicine, University of Bern, 3010 Bern, Switzerland.
| | - Lan Yuan
- Peking University Medical and Health Analysis Center, Peking University Health Science Center, Beijing, China.
| | - Guomei Zhao
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Rui Wang
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Xianjie Cai
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Ze Teng
- Department of Radiology, Cancer Hospital Chinese Academy of Medical Sciences, Beijing, China.
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31
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Abe Y, Takata N, Sakai Y, Hamada HT, Hiraoka Y, Aida T, Tanaka K, Bihan DL, Doya K, Tanaka KF. Diffusion functional MRI reveals global brain network functional abnormalities driven by targeted local activity in a neuropsychiatric disease mouse model. Neuroimage 2020; 223:117318. [PMID: 32882386 DOI: 10.1016/j.neuroimage.2020.117318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
Diffusion functional magnetic resonance imaging (DfMRI) has been proposed as an alternative functional imaging method to detect brain activity without confounding hemodynamic effects. Here, taking advantage of this DfMRI feature, we investigated abnormalities of dynamic brain function in a neuropsychiatric disease mouse model (glial glutamate transporter-knockdown mice with obsessive-compulsive disorder [OCD]-related behavior). Our DfMRI approaches consisted of three analyses: resting state brain activity, functional connectivity, and propagation of neural information. We detected hyperactivation and biased connectivity across the cortico-striatal-thalamic circuitry, which is consistent with known blood oxygen-level dependent (BOLD)-fMRI patterns in OCD patients. In addition, we performed ignition-driven mean integration (IDMI) analysis, which combined activity and connectivity analyses, to evaluate neural propagation initiated from brain activation. This analysis revealed an unbalanced distribution of neural propagation initiated from intrinsic local activation to the global network, while these were not detected by the conventional method with BOLD-fMRI. This abnormal function detected by DfMRI was associated with OCD-related behavior. Together, our comprehensive DfMRI approaches can successfully provide information on dynamic brain function in normal and diseased brains.
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Affiliation(s)
- Yoshifumi Abe
- Departemnt of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, Japan.
| | - Norio Takata
- Departemnt of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, Japan
| | - Yuki Sakai
- ATR Brain Information Communication Research Laboratory Group, Kyoto, Japan; Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hiro Taiyo Hamada
- Neural Computation Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Yuichi Hiraoka
- Department of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, Japan
| | - Tomomi Aida
- Department of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, Japan
| | - Kohichi Tanaka
- Department of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, Japan
| | - Denis Le Bihan
- NeuroSpin, Commissariat à l'énergie atomique et aux énergies alternatives, Gif-sur-Yvette, France; Department of System Neuroscience, National Institutes for Physiological Sciences, Okazaki, Japan
| | - Kenji Doya
- Neural Computation Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Kenji F Tanaka
- Departemnt of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, Japan
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32
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Komaki Y, Debacker C, Djemai B, Ciobanu L, Tsurugizawa T, Bihan DL. Differential effects of aquaporin-4 channel inhibition on BOLD fMRI and diffusion fMRI responses in mouse visual cortex. PLoS One 2020; 15:e0228759. [PMID: 32437449 PMCID: PMC7241787 DOI: 10.1371/journal.pone.0228759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/07/2020] [Indexed: 12/13/2022] Open
Abstract
The contribution of astrocytes to the BOLD fMRI and DfMRI responses in visual cortex of mice following visual stimulation was investigated using TGN-020, an aquaporin 4 (AQP4) channel blocker, acting as an astrocyte function perturbator. Under TGN-020 injection the amplitude of the BOLD fMRI response became significantly higher. In contrast no significant changes in the DfMRI responses and the electrophysiological responses were observed. Those results further confirm the implications of astrocytes in the neurovascular coupling mechanism underlying BOLD fMRI, but not in the DfMRI responses which remained unsensitive to astrocyte function perturbation.
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Affiliation(s)
- Yuji Komaki
- NeuroSpin/Joliot, CEA-Saclay Center, Gif-sur-Yvette, France
| | | | - Boucif Djemai
- NeuroSpin/Joliot, CEA-Saclay Center, Gif-sur-Yvette, France
| | - Luisa Ciobanu
- NeuroSpin/Joliot, CEA-Saclay Center, Gif-sur-Yvette, France
| | | | - Denis Le Bihan
- NeuroSpin/Joliot, CEA-Saclay Center, Gif-sur-Yvette, France
- * E-mail:
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33
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Mandino F, Cerri DH, Garin CM, Straathof M, van Tilborg GAF, Chakravarty MM, Dhenain M, Dijkhuizen RM, Gozzi A, Hess A, Keilholz SD, Lerch JP, Shih YYI, Grandjean J. Animal Functional Magnetic Resonance Imaging: Trends and Path Toward Standardization. Front Neuroinform 2020; 13:78. [PMID: 32038217 PMCID: PMC6987455 DOI: 10.3389/fninf.2019.00078] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 12/19/2019] [Indexed: 12/21/2022] Open
Abstract
Animal whole-brain functional magnetic resonance imaging (fMRI) provides a non-invasive window into brain activity. A collection of associated methods aims to replicate observations made in humans and to identify the mechanisms underlying the distributed neuronal activity in the healthy and disordered brain. Animal fMRI studies have developed rapidly over the past years, fueled by the development of resting-state fMRI connectivity and genetically encoded neuromodulatory tools. Yet, comparisons between sites remain hampered by lack of standardization. Recently, we highlighted that mouse resting-state functional connectivity converges across centers, although large discrepancies in sensitivity and specificity remained. Here, we explore past and present trends within the animal fMRI community and highlight critical aspects in study design, data acquisition, and post-processing operations, that may affect the results and influence the comparability between studies. We also suggest practices aimed to promote the adoption of standards within the community and improve between-lab reproducibility. The implementation of standardized animal neuroimaging protocols will facilitate animal population imaging efforts as well as meta-analysis and replication studies, the gold standards in evidence-based science.
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Affiliation(s)
- Francesca Mandino
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Singapore
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Domenic H. Cerri
- Center for Animal MRI, Department of Neurology, Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Clement M. Garin
- Direction de la Recherche Fondamentale, MIRCen, Institut de Biologie François Jacob, Commissariat à l’Énergie Atomique et aux Énergies Alternatives, Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Milou Straathof
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Geralda A. F. van Tilborg
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - M. Mallar Chakravarty
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
- Department of Biological and Biomedical Engineering, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
| | - Marc Dhenain
- Direction de la Recherche Fondamentale, MIRCen, Institut de Biologie François Jacob, Commissariat à l’Énergie Atomique et aux Énergies Alternatives, Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Rick M. Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Alessandro Gozzi
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Centre for Neuroscience and Cognitive Systems @ UNITN, Rovereto, Italy
| | - Andreas Hess
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich–Alexander University Erlangen–Nürnberg, Erlangen, Germany
| | - Shella D. Keilholz
- Department of Biomedical Engineering, Georgia Tech, Emory University, Atlanta, GA, United States
| | - Jason P. Lerch
- Hospital for Sick Children, Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Wellcome Centre for Integrative NeuroImaging, University of Oxford, Oxford, United Kingdom
| | - Yen-Yu Ian Shih
- Center for Animal MRI, Department of Neurology, Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Joanes Grandjean
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Singapore
- Department of Radiology and Nuclear Medicine, Donders Institute for Brain, Cognition, and Behaviour, Donders Institute, Radboud University Medical Center, Nijmegen, Netherlands
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34
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Albers F, Wachsmuth L, Schache D, Lambers H, Faber C. Functional MRI Readouts From BOLD and Diffusion Measurements Differentially Respond to Optogenetic Activation and Tissue Heating. Front Neurosci 2019; 13:1104. [PMID: 31708721 PMCID: PMC6821691 DOI: 10.3389/fnins.2019.01104] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/01/2019] [Indexed: 12/12/2022] Open
Abstract
Functional blood-oxygenation-level-dependent (BOLD) MRI provides a brain-wide readout that depends on the hemodynamic response to neuronal activity. Diffusion fMRI has been proposed as an alternative to BOLD fMRI and has been postulated to directly rely on neuronal activity. These complementary functional readouts are versatile tools to be combined with optogenetic stimulation to investigate networks of the brain. The cell-specificity and temporal precision of optogenetic manipulations promise to enable further investigation of the origin of fMRI signals. The signal characteristics of the diffusion fMRI readout vice versa may better resolve network effects of optogenetic stimulation. However, the light application needed for optogenetic stimulation is accompanied by heat deposition within the tissue. As both diffusion and BOLD are sensitive to temperature changes, light application can lead to apparent activations confounding the interpretation of fMRI data. The degree of tissue heating, the appearance of apparent activation in different fMRI sequences and the origin of these phenomena are not well understood. Here, we disentangled apparent activations in BOLD and diffusion measurements in rats from physiological activation upon sensory or optogenetic stimulation. Both, BOLD and diffusion fMRI revealed similar signal shapes upon sensory stimulation that differed clearly from those upon heating. Apparent activations induced by high-intensity light application were dominated by T2∗-effects and resulted in mainly negative signal changes. We estimated that even low-intensity light application used for optogenetic stimulation reduces the BOLD response close to the fiber by up to 0.4%. The diffusion fMRI signal contained T2, T2∗ and diffusion components. The apparent diffusion coefficient, which reflects the isolated diffusion component, showed negative changes upon both optogenetic and electric forepaw stimulation. In contrast, positive changes were detected upon high-intensity light application and thus ruled out heating as a major contributor to the diffusion fMRI signal.
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Affiliation(s)
- Franziska Albers
- Translational Research Imaging Center, Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Lydia Wachsmuth
- Translational Research Imaging Center, Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Daniel Schache
- Translational Research Imaging Center, Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Henriette Lambers
- Translational Research Imaging Center, Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Cornelius Faber
- Translational Research Imaging Center, Department of Clinical Radiology, University Hospital Münster, Münster, Germany
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35
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Lizarbe B, Fernández-Pérez A, Caz V, Largo C, Vallejo M, López-Larrubia P, Cerdán S. Systemic Glucose Administration Alters Water Diffusion and Microvascular Blood Flow in Mouse Hypothalamic Nuclei - An fMRI Study. Front Neurosci 2019; 13:921. [PMID: 31551685 PMCID: PMC6733885 DOI: 10.3389/fnins.2019.00921] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/16/2019] [Indexed: 12/23/2022] Open
Abstract
The hypothalamus is the principal regulator of global energy balance, enclosing additionally essential neuronal centers for glucose-sensing and osmoregulation. Disturbances in these tightly regulated neuronal networks are thought to underlie the development of severe pandemic syndromes, including obesity and diabetes. In this work, we investigate in vivo the response of individual hypothalamic nuclei to the i.p. administration of glucose or vehicle solutions, using two groups of adult male C57BL6/J fasted mice and a combination of non-invasive T2∗-weighted and diffusion-weighted functional magnetic resonance imaging (fMRI) approaches. MRI parameters were assessed in both groups of animals before, during and in a post-stimulus phase, following the administration of glucose or vehicle solutions. Hypothalamic nuclei depicted different patterns of activation characterized by: (i) generalized glucose-induced increases of neuronal activation and perfusion-markers in the lateral hypothalamus, arcuate and dorsomedial nuclei, (ii) cellular shrinking events and decreases in microvascular blood flow in the dorsomedial, ventromedial and lateral hypothalamus, following the administration of vehicle solutions and (iii) increased neuronal activity markers and decreased microperfusion parameters in the ARC nuclei of vehicle-administered animals. Immunohistochemical studies performed after the post-stimulus phase confirmed the presence of c-Fos immunoreactive neurons in the arcuate nucleus (ARC) from both animal groups, with significantly higher numbers in the glucose-treated animals. Together, our results reveal that fMRI methods are able to detect in vivo diverse patterns of glucose or vehicle-induced effects in the different hypothalamic nuclei.
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Affiliation(s)
- Blanca Lizarbe
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain
| | - Antonio Fernández-Pérez
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (Ciberdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Victor Caz
- Departamento de Cirugía Experimental, Instituto de Investigación Hospital Universitario La Paz - IdiPAZ, Madrid, Spain
| | - Carlota Largo
- Departamento de Cirugía Experimental, Instituto de Investigación Hospital Universitario La Paz - IdiPAZ, Madrid, Spain
| | - Mario Vallejo
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (Ciberdem), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Sebastián Cerdán
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain
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36
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The impact of fasting on resting state brain networks in mice. Sci Rep 2019; 9:2976. [PMID: 30814613 PMCID: PMC6393589 DOI: 10.1038/s41598-019-39851-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 02/04/2019] [Indexed: 11/18/2022] Open
Abstract
Fasting is known to influence learning and memory in mice and alter the neural networks that subserve these cognitive functions. We used high-resolution functional MRI to study the impact of fasting on resting-state functional connectivity in mice following 12 h of fasting. The cortex and subcortex were parcellated into 52 subregions and functional connectivity was measured between each pair of subregions in groups of fasted and non-fasted mice. Functional connectivity was globally increased in the fasted group compared to the non-fasted group, with the most significant increases evident between the hippocampus (bilateral), retrosplenial cortex (left), visual cortex (left) and auditory cortex (left). Functional brain networks in the non-fasted group comprised five segregated modules of strongly interconnected subregions, whereas the fasted group comprised only three modules. The amplitude of low frequency fluctuations (ALFF) was decreased in the ventromedial hypothalamus in the fasted group. Correlation in gamma oscillations derived from local field potentials was increased between the left visual and retrosplenial cortices in the fasted group and the power of gamma oscillations was reduced in the ventromedial hypothalamus. These results indicate that fasting induces profound changes in functional connectivity, most likely resulting from altered coupling of neuronal gamma oscillations.
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37
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Abe Y, Komaki Y, Seki F, Shibata S, Okano H, Tanaka KF. Correlative study using structural MRI and super-resolution microscopy to detect structural alterations induced by long-term optogenetic stimulation of striatal medium spiny neurons. Neurochem Int 2019; 125:163-174. [PMID: 30825601 DOI: 10.1016/j.neuint.2019.02.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 02/20/2019] [Accepted: 02/22/2019] [Indexed: 11/27/2022]
Abstract
Striatal medium spiny neurons (MSNs) control motor function. Hyper- or hypo-activity of MSNs coincides with basal ganglia-related movement disorders. Based on the assumption that lasting alterations in neuronal activity lead to structural changes in the brain, understanding these structural alterations may be used to infer MSN functional abnormalities. To infer MSN function from structural data, understanding how long-lasting alterations in MSN activity affect brain morphology is essential. To address this, we utilized a simplified model of functional induction by stimulating MSNs expressing channelrhodopsin 2 (ChR2). Subsequent structural alterations which induced long-term activity changes in these MSNs were investigated in the striatal pathway and its associated regions by diffusion tensor imaging (DTI) and histological assessment with super-resolution microscopy. DTI detected changes in the striatum, substantia nigra, and motor cortex. Histological assessment found a reduction in the diameter of myelinated cortical axons as well as MSN dendrites and axons. The structural changes showed a high correlation between DTI parameters and histological data. These results demonstrated that long-term neural activation in the MSNs alters the diameter of MSN and cortical neurons fibers. This study provides a tool for understanding the causal relationship between functional and structural alterations.
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Affiliation(s)
- Yoshifumi Abe
- Department of Neuropsychiatry, Keio University School of Medicine, Japan.
| | - Yuji Komaki
- Department of Physiology, Keio University School of Medicine, Japan; Live Imaging Center, Central Institute for Experimental Animals, Japan
| | - Fumiko Seki
- Department of Physiology, Keio University School of Medicine, Japan; Live Imaging Center, Central Institute for Experimental Animals, Japan
| | - Shinsuke Shibata
- Department of Physiology, Keio University School of Medicine, Japan; Electron Microscope Laboratory, Keio University School of Medicine, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Japan; Electron Microscope Laboratory, Keio University School of Medicine, Japan; Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Japan
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38
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Demiral ŞB, Tomasi D, Sarlls J, Lee H, Wiers CE, Zehra A, Srivastava T, Ke K, Shokri-Kojori E, Freeman CR, Lindgren E, Ramirez V, Miller G, Bandettini P, Horovitz S, Wang GJ, Benveniste H, Volkow ND. Apparent diffusion coefficient changes in human brain during sleep - Does it inform on the existence of a glymphatic system? Neuroimage 2019; 185:263-273. [PMID: 30342236 PMCID: PMC6289767 DOI: 10.1016/j.neuroimage.2018.10.043] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 10/05/2018] [Accepted: 10/17/2018] [Indexed: 01/24/2023] Open
Abstract
The role of sleep in brain physiology is poorly understood. Recently rodent studies have shown that the glymphatic system clears waste products from brain more efficiently during sleep compared to wakefulness due to the expansion of the interstitial fluid space facilitating entry of cerebrospinal fluid (CSF) into the brain. Here, we studied water diffusivity in the brain during sleep and awake conditions, hypothesizing that an increase in water diffusivity during sleep would occur concomitantly with an expansion of CSF volume - an effect that we predicted based on preclinical findings would be most prominent in cerebellum. 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 in 20 of whom we compared rested-wakefulness versus wakefulness following one night of sleep-deprivation. Sleep compared to wakefulness was associated with increases in slow-ADC in cerebellum and left temporal pole and with decreases in fast-ADC in thalamus, insula, parahippocampus and striatal regions, and the density of sleep arousals was inversely associated with ADC changes. The CSF volume was also increased during sleep and was associated with sleep-induced changes in ADCs in cerebellum. There were no differences in ADCs with wakefulness following sleep deprivation compared to rested-wakefulness. Although we hypothesized increases in ADC with sleep, our findings uncovered both increases in slow ADC (mostly in cerebellum) as well as decreases in fast ADC, which could reflect the distinct biological significance of fast- and slow-ADC values in relation to sleep. While preliminary, our findings suggest a more complex sleep-related glymphatic function in the human brain compared to rodents. 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.
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Affiliation(s)
- Şükrü Barış Demiral
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA; Behavioral Biology Branch, Center for Military Psychiatry and Neuroscience Research, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Dardo Tomasi
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Joelle Sarlls
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Corinde E Wiers
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Amna Zehra
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Tansha Srivastava
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Kenneth Ke
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Ehsan Shokri-Kojori
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Clara R Freeman
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Elsa Lindgren
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Veronica Ramirez
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Gregg Miller
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Peter Bandettini
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Silvina Horovitz
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Gene-Jack Wang
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Nora D Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA; National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA.
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39
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Nunes D, Ianus A, Shemesh N. Layer-specific connectivity revealed by diffusion-weighted functional MRI in the rat thalamocortical pathway. Neuroimage 2019; 184:646-657. [PMID: 30267858 PMCID: PMC6264401 DOI: 10.1016/j.neuroimage.2018.09.050] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 12/18/2022] Open
Abstract
Investigating neural activity from a global brain perspective in-vivo has been in the domain of functional Magnetic Resonance Imaging (fMRI) over the past few decades. The intricate neurovascular couplings that govern fMRI's blood-oxygenation-level-dependent (BOLD) functional contrast are invaluable in mapping active brain regions, but they also entail significant limitations, such as non-specificity of the signal to active foci. Diffusion-weighted functional MRI (dfMRI) with relatively high diffusion-weighting strives to ameliorate this shortcoming as it offers functional contrasts more intimately linked with the underlying activity. Insofar, apart from somewhat smaller activation foci, dfMRI's contrasts have not been convincingly shown to offer significant advantages over BOLD-driven fMRI, and its activation maps relied on significant modelling. Here, we study whether dfMRI could offer a better representation of neural activity in the thalamocortical pathway compared to its (spin-echo (SE)) BOLD counterpart. Using high-end forepaw stimulation experiments in the rat at 9.4 T, and with significant sensitivity enhancements due to the use of cryocoils, we show for the first time that dfMRI signals exhibit layer specificity, and, additionally, display signals in areas devoid of SE-BOLD responses. We find that dfMRI signals in the thalamocortical pathway cohere with each other, namely, dfMRI signals in the ventral posterolateral (VPL) thalamic nucleus cohere specifically with layers IV and V in the somatosensory cortex. These activity patterns are much better correlated (compared with SE-BOLD signals) with literature-based electrophysiological recordings in the cortex as well as thalamus. All these findings suggest that dfMRI signals better represent the underlying neural activity in the pathway. In turn, these advanatages may have significant implications towards a much more specific and accurate mapping of neural activity in the global brain in-vivo.
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Affiliation(s)
- Daniel Nunes
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Andrada Ianus
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal; Centre for Medical Image Computing, University College London, London, UK
| | - Noam Shemesh
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.
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40
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Juttukonda MR, Franco G, Englot DJ, Lin YC, Petersen KJ, Trujillo P, Hedera P, Landman BA, Kang H, Donahue MJ, Konrad PE, Dawant BM, Claassen DO. White matter differences between essential tremor and Parkinson disease. Neurology 2018; 92:e30-e39. [PMID: 30504432 DOI: 10.1212/wnl.0000000000006694] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/05/2018] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To assess white matter integrity in patients with essential tremor (ET) and Parkinson disease (PD) with moderate to severe motor impairment. METHODS Sedated participants with ET (n = 57) or PD (n = 99) underwent diffusion tensor imaging (DTI) and fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity values were computed. White matter tracts were defined using 3 well-described atlases. To determine candidate white matter regions that differ between ET and PD groups, a bootstrapping analysis was applied using the least absolute shrinkage and selection operator. Linear regression was applied to assess magnitude and direction of differences in DTI metrics between ET and PD populations in the candidate regions. RESULTS Fractional anisotropy values that differentiate ET from PD localize primarily to thalamic and visual-related pathways, while diffusivity differences localized to the cerebellar peduncles. Patients with ET exhibited lower fractional anisotropy values than patients with PD in the lateral geniculate body (p < 0.01), sagittal stratum (p = 0.01), forceps major (p = 0.02), pontine crossing tract (p = 0.03), and retrolenticular internal capsule (p = 0.04). Patients with ET exhibited greater radial diffusivity values than patients with PD in the superior cerebellar peduncle (p < 0.01), middle cerebellar peduncle (p = 0.05), and inferior cerebellar peduncle (p = 0.05). CONCLUSIONS Regionally, distinctive white matter microstructural values in patients with ET localize to the cerebellar peduncles and thalamo-cortical visual pathways. These findings complement recent functional imaging studies in ET but also extend our understanding of putative physiologic features that account for distinctions between ET and PD.
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Affiliation(s)
- Meher R Juttukonda
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Giulia Franco
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Dario J Englot
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Ya-Chen Lin
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Kalen J Petersen
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Paula Trujillo
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Peter Hedera
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Bennett A Landman
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Hakmook Kang
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Manus J Donahue
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Peter E Konrad
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Benoit M Dawant
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN
| | - Daniel O Claassen
- From the Departments of Radiology and Radiological Sciences (M.R.J., M.J.D.), Neurological Surgery (D.J.E., P.E.K.), Biostatistics (Y.-C.L., H.K.), Neurology (P.T., P.H., M.J.D.), and Psychiatry (M.J.D.), Vanderbilt University Medical Center, Nashville, TN; Department of Pathophysiology and Transplantation (G.F.) University of Milan, Italy; and Chemical and Physical Biology Program (K.J.P.) and Departments of Electrical Engineering (B.A.L., B.M.D.), Computer Engineering (B.A.L., B.M.D.), Computer Science and Biomedical Engineering (B.A.L., B.M.D.), and Neurology (D.O.C.), Vanderbilt University, Nashville, TN.
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Bydder M, Zaaraoui W, Ridley B, Soubrier M, Bertinetti M, Confort-Gouny S, Schad L, Guye M, Ranjeva JP. Dynamic 23Na MRI - A non-invasive window on neuroglial-vascular mechanisms underlying brain function. Neuroimage 2018; 184:771-780. [PMID: 30292814 DOI: 10.1016/j.neuroimage.2018.09.071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 09/21/2018] [Accepted: 09/25/2018] [Indexed: 11/17/2022] Open
Abstract
A novel magnetic resonance imaging (MRI) acquisition and reconstruction method for obtaining a series of dynamic sodium 23Na-MRI acquisitions was designed to non-invasively assess the signal variations of brain sodium during a hand motor task in 14 healthy human volunteers on an ultra high field (7T) MR scanner. Regions undergoing activation and deactivation were identified with reference to conventional task-related BOLD functional MRI (fMRI). Activation observed in the left central regions, the supplementary motor areas and the left cerebellum induced an increase in the sodium signal observed at ultra short echo time and a decrease in the 23Na signal observed at long echo time. Based on a simple model of two distinct sodium pools (namely, restricted and mobile sodium), the ultra short echo time measures the totality of sodium whereas the long echo time is mainly sensitive to mobile sodium. This activation pattern is consistent with previously described processes related to an influx of Na+ into the intracellular compartments and a moderate increase in the cerebral blood volume (CBV). In contrast, deactivation observed in the right central regions ipsilateral to the movement, the precuneus and the left cerebellum induced a slight decrease in sodium signal at ultra short echo time and an increase of sodium signal at longer echo times. This inhibitory pattern is compatible with a slight decrease in CBV and an efflux of intracellular Na+ to the extracellular compartments that may reflect neural dendritic spine and astrocytic shrinkage, and an increase of sodium in the extracellular fraction. In conclusion, cerebral dynamic 23Na MRI experiments can provide access to the ionic transients following a functional task occurring within the neuro-glial-vascular ensemble. This has the potential to open up a novel non-invasive window on the mechanisms underlying brain function.
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Affiliation(s)
- Mark Bydder
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Wafaa Zaaraoui
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Ben Ridley
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Manon Soubrier
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Marie Bertinetti
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Sylviane Confort-Gouny
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Lothar Schad
- Computer Assisted Clinical Medicine, Centre for Biomedicine and Medical Technology Mannheim, Heidelberg University, Mannheim, Germany
| | - Maxime Guye
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France
| | - Jean-Philippe Ranjeva
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France; APHM, University Hospital Timone, CEMEREM, Marseille, France.
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Springer CS. Using 1H 2O MR to measure and map sodium pump activity in vivo. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:110-126. [PMID: 29705043 DOI: 10.1016/j.jmr.2018.02.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 02/16/2018] [Accepted: 02/26/2018] [Indexed: 05/26/2023]
Abstract
The cell plasma membrane Na+,K+-ATPase [NKA] is one of biology's most [if not the most] significant enzymes. By actively transporting Na+ out [and K+ in], it maintains the vital trans-membrane ion concentration gradients and the membrane potential. The forward NKA reaction is shown in the Graphical Abstract [which is elaborated in the text]. Crucially, NKA does not operate in isolation. There are other transporters that conduct K+ back out of [II, Graphical Abstract] and Na+ back into [III, Graphical Abstract] the cell. Thus, NKA must function continually. Principal routes for ATP replenishment include mitochondrial oxidative phosphorylation, glycolysis, and creatine kinase [CrK] activity. However, it has never been possible to measure, let alone map, this integrated, cellular homeostatic NKA activity in vivo. Active trans-membrane water cycling [AWC] promises a way to do this with 1H2O MR. Inthe Graphical Abstract, the AWC system is characterized by active contributions totheunidirectional rate constants for steady-state water efflux and influx, respectively, kio(a) and koi(a). The discovery, validation, and initial exploration of active water cycling are reviewed here. Promising applications in cancer, cardiological, and neurological MRI are covered. This initial work employed paramagnetic Gd(III)chelate contrast agents [CAs]. However, the significant problems associated with in vivo CA use are also reviewed. A new analysis of water diffusion-weighted MRI [DWI] is presented. Preliminary results suggest a non-invasive way to measure the cell number density [ρ (cells/μL)], the mean cell volume [V (pL)], and the cellular NKA metabolic rate [cMRNKA(fmol(ATP)/s/cell)] with high spatial resolution. These crucial cell biology properties have not before been accessible invivo. Furthermore, initial findings indicate their absolute values can be determined.
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Affiliation(s)
- Charles S Springer
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR 97239, United States.
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Kitamura A, Hojo Y, Ikeda M, Karakawa S, Kuwahara T, Kim J, Soma M, Kawato S, Tsurugizawa T. Ingested d-Aspartate Facilitates the Functional Connectivity and Modifies Dendritic Spine Morphology in Rat Hippocampus. Cereb Cortex 2018; 29:2499-2508. [DOI: 10.1093/cercor/bhy120] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Indexed: 12/11/2022] Open
Affiliation(s)
- Akihiko Kitamura
- Institute for Innovation, Ajinomoto Co., Inc., Suzuki-cho 1-1, Kawasaki-ku, Kawasaki, Japan
| | - Yasushi Hojo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Muneki Ikeda
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Kaga 2-11-1, Itabashi, Tokyo, Japan
| | - Sachise Karakawa
- Institute for Innovation, Ajinomoto Co., Inc., Suzuki-cho 1-1, Kawasaki-ku, Kawasaki, Japan
| | - Tomomi Kuwahara
- Institute for Innovation, Ajinomoto Co., Inc., Suzuki-cho 1-1, Kawasaki-ku, Kawasaki, Japan
| | - Jonghyuk Kim
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Kaga 2-11-1, Itabashi, Tokyo, Japan
| | - Mika Soma
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Kaga 2-11-1, Itabashi, Tokyo, Japan
| | - Suguru Kawato
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Kaga 2-11-1, Itabashi, Tokyo, Japan
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Ianuş A, Shemesh N. Incomplete initial nutation diffusion imaging: An ultrafast, single-scan approach for diffusion mapping. Magn Reson Med 2017; 79:2198-2204. [PMID: 28868785 PMCID: PMC5836954 DOI: 10.1002/mrm.26894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 01/22/2023]
Abstract
Purpose Diffusion MRI is confounded by the need to acquire at least two images separated by a repetition time, thereby thwarting the detection of rapid dynamic microstructural changes. The issue is exacerbated when diffusivity variations are accompanied by rapid changes in T2. The purpose of the present study is to accelerate diffusion MRI acquisitions such that both reference and diffusion‐weighted images necessary for quantitative diffusivity mapping are acquired in a single‐shot experiment. Methods A general methodology termed incomplete initial nutation diffusion imaging (INDI), capturing two diffusion contrasts in a single shot, is presented. This methodology creates a longitudinal magnetization reservoir that facilitates the successive acquisition of two images separated by only a few milliseconds. The theory behind INDI is presented, followed by proof‐of‐concept studies in water phantom, ex vivo, and in vivo experiments at 16.4 and 9.4 T. Results Mean diffusivities extracted from INDI were comparable with diffusion tensor imaging and the two‐shot isotropic diffusion encoding in the water phantom. In ex vivo mouse brain tissues, as well as in the in vivo mouse brain, mean diffusivities extracted from conventional isotropic diffusion encoding and INDI were in excellent agreement. Simulations for signal‐to‐noise considerations identified the regimes in which INDI is most beneficial. Conclusions The INDI method accelerates diffusion MRI acquisition to single‐shot mode, which can be of great importance for mapping dynamic microstructural properties in vivo without T2 bias. Magn Reson Med 79:2198–2204, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Andrada Ianuş
- Champalimaud Neuroscience Programme, Champalimaud Centre for the UnknownLisbonPortugal
- Centre for Medical Image Computing, Department of Computer ScienceUniversity College LondonUnited Kingdom
| | - Noam Shemesh
- Champalimaud Neuroscience Programme, Champalimaud Centre for the UnknownLisbonPortugal
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Abe Y, Van Nguyen K, Tsurugizawa T, Ciobanu L, Le Bihan D. Modulation of water diffusion by activation-induced neural cell swelling in Aplysia Californica. Sci Rep 2017; 7:6178. [PMID: 28733682 PMCID: PMC5522485 DOI: 10.1038/s41598-017-05586-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/31/2017] [Indexed: 01/26/2023] Open
Abstract
Diffusion functional magnetic resonance imaging (DfMRI) has been proposed as a method for functional neuroimaging studies, as an alternative to blood oxygenation level dependent (BOLD)-fMRI. DfMRI is thought to more directly reflect neural activation, but its exact mechanism remains unclear. It has been hypothesized that the water apparent diffusion coefficient (ADC) decrease observed upon neural activation results from swelling of neurons or neuron parts. To elucidate the origin of the DfMRI response at cellular level we performed diffusion MR microscopy at 17.2 T in Aplysia californica buccal ganglia and compared the water ADCs at cellular and ganglia levels before and after neuronal activation induced by perfusion with a solution containing dopamine. Neural cell swelling, evidenced from optical microscopy imaging, resulted in an intracellular ADC increase and an ADC decrease at ganglia level. Furthermore, the intracellular ADC increase was found to have a significant positive correlation with the increase in cell size. Our results strongly support the hypothesis that the ADC decrease observed with DfMRI upon neuronal activation at tissue level reflects activation-induced neural cell swelling.
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Affiliation(s)
- Yoshifumi Abe
- NeuroSpin, Bât 145, Joliot Institute, CEA-Paris-Saclay Center, Point Courrier 156, 91191, Gif-sur-Yvette, France
| | - Khieu Van Nguyen
- NeuroSpin, Bât 145, Joliot Institute, CEA-Paris-Saclay Center, Point Courrier 156, 91191, Gif-sur-Yvette, France.,University Paris-Saclay, 15 rue Georges Clemenceau, 91400, Orsay, France
| | - Tomokazu Tsurugizawa
- NeuroSpin, Bât 145, Joliot Institute, CEA-Paris-Saclay Center, Point Courrier 156, 91191, Gif-sur-Yvette, France
| | - Luisa Ciobanu
- NeuroSpin, Bât 145, Joliot Institute, CEA-Paris-Saclay Center, Point Courrier 156, 91191, Gif-sur-Yvette, France
| | - Denis Le Bihan
- NeuroSpin, Bât 145, Joliot Institute, CEA-Paris-Saclay Center, Point Courrier 156, 91191, Gif-sur-Yvette, France.
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