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Xing H, Wu Z, Chang Y, Ma M, Song Z, Liu Y, Dai H. Resting-State fMRI Study of Vigilance Under Circadian and Homeostatic Modulation Based on Fractional Amplitude of Low-Frequency Fluctuation and Regional Homogeneity in Humans Under Normal Entrained Conditions. J Magn Reson Imaging 2024; 59:211-222. [PMID: 37078514 DOI: 10.1002/jmri.28750] [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: 02/09/2023] [Revised: 04/10/2023] [Accepted: 04/10/2023] [Indexed: 04/21/2023] Open
Abstract
BACKGROUND How brain neural activity changes at multiple time points throughout the day and the neural mechanisms underlying time-dependent modulation of vigilance are less clear. PURPOSE To explore the effect of circadian rhythms and homeostasis on brain neural activity and the potential neural basis of time-dependent modulation of vigilance. STUDY TYPE Prospective. SUBJECTS A total of 30 healthy participants (22-27 years old). FIELD STRENGTH/SEQUENCE A 3.0 T, T1-weighted imaging, echo-planar functional MRI (fMRI). ASSESSMENT Six resting-state fMRI (rs-fMRI) scanning sessions were performed at fixed times (9:00 h, 13:00 h, 17:00 h, 21:00 h, 1:00 h, and 5:00 h) to investigate fractional amplitude of low-frequency fluctuation (fALFF) and regional homogeneity (ReHo) diurnal variation. The fALFF/ReHo and the result of the psychomotor vigilance task were used to assess local neural activity and vigilance. STATISTICAL TESTS One-way repeated measures analysis of variance (ANOVA) was used to assess changes in vigilance (P < 0.05) and neural activity in the whole brain (P < 0.001 at the voxel level and P < 0.01 at the cluster level, Gaussian random field [GRF] corrected). Correlation analysis was used to examine the relationship between neural activity and vigilance at all-time points of the day. RESULTS The fALFF/ReHo in the thalamus and some perceptual cortices tended to increase from 9:00 h to 13:00 h and from 21:00 h to 5:00 h, whereas the key nodes of the default mode network (DMN) tended to decrease from 21:00 h to 5:00 h. The vigilance tended to decrease from 21:00 h to 5:00 h. The fALFF/ReHo in the thalamus and some perceptual cortices was negatively correlated with vigilance at all-time points of the day, whereas the fALFF/ReHo in the key nodes of the DMN was positively correlated with vigilance. DATA CONCLUSION Neural activities in the thalamus and some perceptual cortices show similar trends throughout the day, whereas the key nodes of the DMN show roughly opposite trends. Notably, diurnal variation of the neural activity in these brain regions may be an adaptive or compensatory response to changes in vigilance. EVIDENCE LEVEL 1. TECHNICAL EFFICACY 1.
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Affiliation(s)
- Hanqi Xing
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Zhiwei Wu
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Yue Chang
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Mengya Ma
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Ziyang Song
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Yuanqing Liu
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Hui Dai
- Department of Radiology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, People's Republic of China
- Institute of Medical Imaging, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
- Suzhou Key Laboratory of Intelligent Medicine and Equipment, Suzhou, Jiangsu Province, People's Republic of China
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Wang Z, Donahue EK, Guo Y, Renteln M, Petzinger GM, Jakowec MW, Holschneider DP. Exercise alters cortico-basal ganglia network metabolic connectivity: a mesoscopic level analysis informed by anatomic parcellation defined in the mouse brain connectome. Brain Struct Funct 2023; 228:1865-1884. [PMID: 37306809 PMCID: PMC10516800 DOI: 10.1007/s00429-023-02659-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 05/29/2023] [Indexed: 06/13/2023]
Abstract
The basal ganglia are important modulators of the cognitive and motor benefits of exercise. However, the neural networks underlying these benefits remain poorly understood. Our study systematically analyzed exercise-associated changes in metabolic connectivity in the cortico-basal ganglia-thalamic network during the performance of a new motor task, with regions-of-interest defined based on mesoscopic domains recently defined in the mouse brain structural connectome. Mice were trained on a motorized treadmill for six weeks or remained sedentary (control), thereafter undergoing [14C]-2-deoxyglucose metabolic brain mapping during wheel walking. Regional cerebral glucose uptake (rCGU) was analyzed in 3-dimensional brains reconstructed from autoradiographic brain sections using statistical parametric mapping. Metabolic connectivity was assessed by calculating inter-regional correlation of rCGU cross-sectionally across subjects within a group. Compared to controls, exercised animals showed broad decreases in rCGU in motor areas, but increases in limbic areas, as well as the visual and association cortices. In addition, exercised animals showed (i) increased positive metabolic connectivity within and between the motor cortex and caudoputamen (CP), (ii) newly emerged negative connectivity of the substantia nigra pars reticulata with the globus pallidus externus, and CP, and (iii) reduced connectivity of the prefrontal cortex (PFC). Increased metabolic connectivity in the motor circuit in the absence of increases in rCGU strongly suggests greater network efficiency, which is also supported by the reduced involvement of PFC-mediated cognitive control during the performance of a new motor task. Our study delineates exercise-associated changes in functional circuitry at the subregional level and provides a framework for understanding the effects of exercise on functions of the cortico-basal ganglia-thalamic network.
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Affiliation(s)
- Zhuo Wang
- Department of Psychiatry and Behavioral Sciences, University of Southern California, 1975 Zonal Avenue, KAM 400, MC9037, Los Angeles, California 90089-9037 USA
| | - Erin K. Donahue
- Graduate Program in Neurosciences, University of Southern California, Los Angeles, California USA
| | - Yumei Guo
- Department of Psychiatry and Behavioral Sciences, University of Southern California, 1975 Zonal Avenue, KAM 400, MC9037, Los Angeles, California 90089-9037 USA
| | - Michael Renteln
- Present Address: Department of Neurology, University of Southern California, Los Angeles, California USA
| | - Giselle M. Petzinger
- Graduate Program in Neurosciences, University of Southern California, Los Angeles, California USA
- Present Address: Department of Neurology, University of Southern California, Los Angeles, California USA
| | - Michael W. Jakowec
- Graduate Program in Neurosciences, University of Southern California, Los Angeles, California USA
- Present Address: Department of Neurology, University of Southern California, Los Angeles, California USA
| | - Daniel P. Holschneider
- Department of Psychiatry and Behavioral Sciences, University of Southern California, 1975 Zonal Avenue, KAM 400, MC9037, Los Angeles, California 90089-9037 USA
- Graduate Program in Neurosciences, University of Southern California, Los Angeles, California USA
- Present Address: Department of Neurology, University of Southern California, Los Angeles, California USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California USA
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The Therapeutic Role of Ketogenic Diet in Neurological Disorders. Nutrients 2022; 14:nu14091952. [PMID: 35565918 PMCID: PMC9102882 DOI: 10.3390/nu14091952] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 02/01/2023] Open
Abstract
The ketogenic diet (KD) is a high-fat, low-carbohydrate and adequate-protein diet that has gained popularity in recent years in the context of neurological diseases (NDs). The complexity of the pathogenesis of these diseases means that effective forms of treatment are still lacking. Conventional therapy is often associated with increasing tolerance and/or drug resistance. Consequently, more effective therapeutic strategies are being sought to increase the effectiveness of available forms of therapy and improve the quality of life of patients. For the moment, it seems that KD can provide therapeutic benefits in patients with neurological problems by effectively controlling the balance between pro- and antioxidant processes and pro-excitatory and inhibitory neurotransmitters, and modulating inflammation or changing the composition of the gut microbiome. In this review we evaluated the potential therapeutic efficacy of KD in epilepsy, depression, migraine, Alzheimer’s disease and Parkinson’s disease. In our opinion, KD should be considered as an adjuvant therapeutic option for some neurological diseases.
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Stevenson R, Samokhina E, Rossetti I, Morley JW, Buskila Y. Neuromodulation of Glial Function During Neurodegeneration. Front Cell Neurosci 2020; 14:278. [PMID: 32973460 PMCID: PMC7473408 DOI: 10.3389/fncel.2020.00278] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022] Open
Abstract
Glia, a non-excitable cell type once considered merely as the connective tissue between neurons, is nowadays acknowledged for its essential contribution to multiple physiological processes including learning, memory formation, excitability, synaptic plasticity, ion homeostasis, and energy metabolism. Moreover, as glia are key players in the brain immune system and provide structural and nutritional support for neurons, they are intimately involved in multiple neurological disorders. Recent advances have demonstrated that glial cells, specifically microglia and astroglia, are involved in several neurodegenerative diseases including Amyotrophic lateral sclerosis (ALS), Epilepsy, Parkinson's disease (PD), Alzheimer's disease (AD), and frontotemporal dementia (FTD). While there is compelling evidence for glial modulation of synaptic formation and regulation that affect neuronal signal processing and activity, in this manuscript we will review recent findings on neuronal activity that affect glial function, specifically during neurodegenerative disorders. We will discuss the nature of each glial malfunction, its specificity to each disorder, overall contribution to the disease progression and assess its potential as a future therapeutic target.
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Affiliation(s)
- Rebecca Stevenson
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Evgeniia Samokhina
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Ilaria Rossetti
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - John W. Morley
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
- International Centre for Neuromorphic Systems, The MARCS Institute for Brain, Behaviour and Development, Penrith, NSW, Australia
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Investigatory pathway and principles of patient selection for epilepsy surgery candidates: a systematic review. BMC Neurol 2020; 20:100. [PMID: 32183734 PMCID: PMC7079385 DOI: 10.1186/s12883-020-01680-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 03/10/2020] [Indexed: 01/20/2023] Open
Abstract
Background The predominant treatment for epilepsy is pharmacotherapy, yet 20–40% do not respond to anti-epileptic drugs. After becoming pharmacoresistant, some patients are worked-up to determine candidacy for epilepsy surgery. Despite the 2009 American Epilepsy Society guidelines, there is no broadly accepted criteria for the investigatory pathway and principles of patient selection for epilepsy surgery candidates. The objective of this systematic review is to elucidate what diagnostic pathways clinicians globally utilize. Methods Utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and the Cochrane Handbook of Systemic Reviews of Interventions, we conducted a systematic review through MEDLINE, Embase, and CENTRAL. Results From 2092 screened articles, 14 met inclusion criteria for qualitative synthesis. Structural MRI was required in all investigatory pathways. All but two articles required neuropsychological assessment. Six required neuropsychiatric assessment. Two protocols mentioned assessing the patient’s support network. Three other protocols mentioned discussing expectations with patients. One also motioned conducing an occupational evaluation and making all surgery decisions in a multidisciplinary management conference. fMRI and the Wada test were required assessments in seven of the protocols. [18F]FDG-PET and SPECT were ancillary for all but three articles (where they were required). MEG and intracranial EEG were only mentioned as ancillary. Magnetic resonance (MR) spectroscopy was required at two institutes. With regards to the actual indication for selecting patients to begin the investigatory pathway, seven of the articles used a variation of the International League Against Epilepsy definition of refectory epilepsy, while one incorporated patient social history. Conclusions Despite attempts to standardize patient selection and investigatory pathways, no two protocols were identical. Scalp video/EEG telemetry, structural MRI, and neuropsychological assessment were the only assessments utilized in nearly all protocols. Socioeconomic restrictions appear to play a role in determining which tests are utilized in the investigatory pathway—not just for developing countries. However, cost-effective assessments, such as assessing patient support network and providing realistic expectation of outcomes, were only utilized in few protocols. In addition, no advanced imaging technologies (i.e., qMRI, 3D-MMI) were utilized. Overall, even amongst expert examiners there is significant variation throughout epilepsy centers globally, in selecting candidates and working up patients.
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Abstract
Huntington's disease (HD) is a fatal, inherited neurodegenerative disorder caused by a mutation in the huntingtin gene (HTT). While mutant HTT is present ubiquitously throughout life, HD onset typically occurs in mid-life, suggesting that aging may play an active role in pathogenesis. Cellular aging is defined as the slow decline in stress resistance and accumulation of damage over time. While different cells and tissues can age at different rates, 9 hallmarks of aging have emerged to better define the cellular aging process. Strikingly, many of the hallmarks of aging are also hallmarks of HD pathology. Models of HD and HD patients possess markers of accelerated aging, and processes that decline during aging also decline at a more rapid rate in HD, further implicating the role of aging in HD pathogenesis. Furthermore, accelerating aging in HD mouse and patient-derived neurons unmasks HD-specific phenotypes, suggesting an active role for the aging process in the onset and progression of HD. Here, we review the overlap between the hallmarks of aging and HD and discuss how aging may contribute to pathogenesis in HD.
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Affiliation(s)
- Emily Machiela
- University of Central Florida, College of Medicine, Burnett School of Biomedical Sciences, Orlando, FL, USA
| | - Amber L. Southwell
- University of Central Florida, College of Medicine, Burnett School of Biomedical Sciences, Orlando, FL, USA
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7
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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8
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Sweeney MD, Montagne A, Sagare AP, Nation DA, Schneider LS, Chui HC, Harrington MG, Pa J, Law M, Wang DJJ, Jacobs RE, Doubal FN, Ramirez J, Black SE, Nedergaard M, Benveniste H, Dichgans M, Iadecola C, Love S, Bath PM, Markus HS, Al-Shahi Salman R, Allan SM, Quinn TJ, Kalaria RN, Werring DJ, Carare RO, Touyz RM, Williams SCR, Moskowitz MA, Katusic ZS, Lutz SE, Lazarov O, Minshall RD, Rehman J, Davis TP, Wellington CL, González HM, Yuan C, Lockhart SN, Hughes TM, Chen CLH, Sachdev P, O'Brien JT, Skoog I, Pantoni L, Gustafson DR, Biessels GJ, Wallin A, Smith EE, Mok V, Wong A, Passmore P, Barkof F, Muller M, Breteler MMB, Román GC, Hamel E, Seshadri S, Gottesman RF, van Buchem MA, Arvanitakis Z, Schneider JA, Drewes LR, Hachinski V, Finch CE, Toga AW, Wardlaw JM, Zlokovic BV. Vascular dysfunction-The disregarded partner of Alzheimer's disease. Alzheimers Dement 2019; 15:158-167. [PMID: 30642436 PMCID: PMC6338083 DOI: 10.1016/j.jalz.2018.07.222] [Citation(s) in RCA: 426] [Impact Index Per Article: 85.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/31/2018] [Indexed: 12/30/2022]
Abstract
Increasing evidence recognizes Alzheimer's disease (AD) as a multifactorial and heterogeneous disease with multiple contributors to its pathophysiology, including vascular dysfunction. The recently updated AD Research Framework put forth by the National Institute on Aging-Alzheimer's Association describes a biomarker-based pathologic definition of AD focused on amyloid, tau, and neuronal injury. In response to this article, here we first discussed evidence that vascular dysfunction is an important early event in AD pathophysiology. Next, we examined various imaging sequences that could be easily implemented to evaluate different types of vascular dysfunction associated with, and/or contributing to, AD pathophysiology, including changes in blood-brain barrier integrity and cerebral blood flow. Vascular imaging biomarkers of small vessel disease of the brain, which is responsible for >50% of dementia worldwide, including AD, are already established, well characterized, and easy to recognize. We suggest that these vascular biomarkers should be incorporated into the AD Research Framework to gain a better understanding of AD pathophysiology and aid in treatment efforts.
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Affiliation(s)
- Melanie D Sweeney
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Axel Montagne
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Abhay P Sagare
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Daniel A Nation
- Department of Psychology, University of Southern California, Los Angeles, CA, USA; Alzheimer's Disease Research Center, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Lon S Schneider
- Alzheimer's Disease Research Center, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Psychiatry and the Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Helena C Chui
- Alzheimer's Disease Research Center, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Judy Pa
- Laboratory of Neuro Imaging (LONI), Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Meng Law
- Alzheimer's Disease Research Center, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA; Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Danny J J Wang
- Laboratory of Neuro Imaging (LONI), Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Russell E Jacobs
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Fergus N Doubal
- Neuroimaging Sciences and Brain Research Imaging Center, Division of Neuroimaging Sciences, Center for Clinical Brain Sciences, UK Dementia Research Institute at the University of Edinburgh, UK
| | - Joel Ramirez
- LC Campbell Cognitive Neurology Research Unit, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada; Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada; Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Sandra E Black
- Department of Medicine (Neurology), Hurvitz Brain Sciences Program, Canadian Partnership for Stroke Recovery, and LC Campbell Cognitive Neurology Research Unit, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto Dementia Research Alliance, University of Toronto, Toronto, Canada
| | - Maiken Nedergaard
- Section for Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Division of Glia Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Martin Dichgans
- Institute for Stroke and Dementia Research (ISD), Ludwing-Maximilians-University Munich, Munich, Germany
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Seth Love
- Institute of Clinical Neurosciences, University of Bristol, School of Medicine, Level 2 Learning and Research, Southmead Hospital, Bristol, UK
| | - Philip M Bath
- Stroke Trials Unit, Division of Clinical Neuroscience, University of Nottingham, City Hospital Campus, Nottingham, UK; Stroke, Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham, UK
| | - Hugh S Markus
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Rustam Al-Shahi Salman
- Neuroimaging Sciences and Brain Research Imaging Center, Division of Neuroimaging Sciences, Center for Clinical Brain Sciences, UK Dementia Research Institute at the University of Edinburgh, UK
| | - Stuart M Allan
- Faculty of Biology, Medicine and Health, Division of Neuroscience and Experimental Psychology, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Terence J Quinn
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Rajesh N Kalaria
- Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - David J Werring
- Stroke Research Centre, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London, UK
| | - Roxana O Carare
- Faculty of Medicine, University of Southampton, Southampton, UK
| | - Rhian M Touyz
- British Heart Foundation, Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - Steve C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Michael A Moskowitz
- Stroke and Neurovascular Regulation Laboratory, Departments of Radiology and Neurology Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - Zvonimir S Katusic
- Department of Anesthesiology and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Sarah E Lutz
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Orly Lazarov
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Richard D Minshall
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA; Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA
| | - Jalees Rehman
- Department of Pharmacology, The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL, USA; Department of Medicine, The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL, USA
| | - Thomas P Davis
- Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - Cheryl L Wellington
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hector M González
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Chun Yuan
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Samuel N Lockhart
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; Alzheimer's Disease Research Center, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Timothy M Hughes
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; Alzheimer's Disease Research Center, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Christopher L H Chen
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Memory Aging and Cognition Centre, National University Health System, Singapore; Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Memory Aging and Cognition Centre, National University Health System, Singapore
| | - Perminder Sachdev
- Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales Australia, Sydney, Australia
| | - John T O'Brien
- Department of Psychiatry, University of Cambridge School of Clinical Medicine, Cambridge, UK
| | - Ingmar Skoog
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden
| | - Leonardo Pantoni
- "L. Sacco" Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Deborah R Gustafson
- Department of Neurology, State University of New York-Downstate Medical Center, Brooklyn, NY, USA
| | - Geert Jan Biessels
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anders Wallin
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenberg, Sweden
| | - Eric E Smith
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Vincent Mok
- Department of Medicine and Therapeutics, Therese Pei Fong Chow Research Centre for Prevention of Dementia, The Chinese University of Hong Kong, Hong Kong SAR, China; Gerald Choa Neuroscience Centre, Lui Che Woo Institute of Innovative Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Adrian Wong
- Department of Medicine and Therapeutics, Therese Pei Fong Chow Research Centre for Prevention of Dementia, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Peter Passmore
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Frederick Barkof
- Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands; Institutes of Neurology and Healthcare Engineering, University College London, London, UK
| | - Majon Muller
- Section of Geriatrics, Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Monique M B Breteler
- Department of Population Health Sciences, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Institute for Medical Biometry, Informatics and Epidemiology (IMBIE), Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Gustavo C Román
- Department of Neurology, Methodist Neurological Institute, Houston, TX, USA
| | - Edith Hamel
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Sudha Seshadri
- The Framingham Heart Study, Framingham, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Rebecca F Gottesman
- Departments of Neurology and Epidemiology, Johns Hopkins University, Baltimore, MD, USA
| | - Mark A van Buchem
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Zoe Arvanitakis
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA; Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Julie A Schneider
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA; Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Lester R Drewes
- Laboratory of Cerebral Vascular Biology, Department of Biomedical Sciences, University of Minnesota Medical School Duluth, Duluth, MN, USA
| | - Vladimir Hachinski
- Division of Neurology, Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada
| | - Caleb E Finch
- Leonard Davis School of Gerontology, Dornsife College, University of Southern California, Los Angeles, CA, USA
| | - Arthur W Toga
- Alzheimer's Disease Research Center, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA; Laboratory of Neuro Imaging (LONI), Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Joanna M Wardlaw
- Neuroimaging Sciences and Brain Research Imaging Center, Division of Neuroimaging Sciences, Center for Clinical Brain Sciences, UK Dementia Research Institute at the University of Edinburgh, UK
| | - Berislav V Zlokovic
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Alzheimer's Disease Research Center, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA.
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Sweeney MD, Sagare AP, Zlokovic BV. Blood-brain barrier breakdown in Alzheimer disease and other neurodegenerative disorders. Nat Rev Neurol 2018; 14:133-150. [PMID: 29377008 PMCID: PMC5829048 DOI: 10.1038/nrneurol.2017.188] [Citation(s) in RCA: 1617] [Impact Index Per Article: 269.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The blood-brain barrier (BBB) is a continuous endothelial membrane within brain microvessels that has sealed cell-to-cell contacts and is sheathed by mural vascular cells and perivascular astrocyte end-feet. The BBB protects neurons from factors present in the systemic circulation and maintains the highly regulated CNS internal milieu, which is required for proper synaptic and neuronal functioning. BBB disruption allows influx into the brain of neurotoxic blood-derived debris, cells and microbial pathogens and is associated with inflammatory and immune responses, which can initiate multiple pathways of neurodegeneration. This Review discusses neuroimaging studies in the living human brain and post-mortem tissue as well as biomarker studies demonstrating BBB breakdown in Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, multiple sclerosis, HIV-1-associated dementia and chronic traumatic encephalopathy. The pathogenic mechanisms by which BBB breakdown leads to neuronal injury, synaptic dysfunction, loss of neuronal connectivity and neurodegeneration are described. The importance of a healthy BBB for therapeutic drug delivery and the adverse effects of disease-initiated, pathological BBB breakdown in relation to brain delivery of neuropharmaceuticals are briefly discussed. Finally, future directions, gaps in the field and opportunities to control the course of neurological diseases by targeting the BBB are presented.
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Affiliation(s)
- Melanie D Sweeney
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Abhay P Sagare
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Berislav V Zlokovic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo Street, Los Angeles, California 90089, USA
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Burroni J, Taylor P, Corey C, Vachnadze T, Siegelmann HT. Energetic Constraints Produce Self-sustained Oscillatory Dynamics in Neuronal Networks. Front Neurosci 2017; 11:80. [PMID: 28289370 PMCID: PMC5326782 DOI: 10.3389/fnins.2017.00080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 02/03/2017] [Indexed: 12/27/2022] Open
Abstract
Overview: We model energy constraints in a network of spiking neurons, while exploring general questions of resource limitation on network function abstractly. Background: Metabolic states like dietary ketosis or hypoglycemia have a large impact on brain function and disease outcomes. Glia provide metabolic support for neurons, among other functions. Yet, in computational models of glia-neuron cooperation, there have been no previous attempts to explore the effects of direct realistic energy costs on network activity in spiking neurons. Currently, biologically realistic spiking neural networks assume that membrane potential is the main driving factor for neural spiking, and do not take into consideration energetic costs. Methods: We define local energy pools to constrain a neuron model, termed Spiking Neuron Energy Pool (SNEP), which explicitly incorporates energy limitations. Each neuron requires energy to spike, and resources in the pool regenerate over time. Our simulation displays an easy-to-use GUI, which can be run locally in a web browser, and is freely available. Results: Energy dependence drastically changes behavior of these neural networks, causing emergent oscillations similar to those in networks of biological neurons. We analyze the system via Lotka-Volterra equations, producing several observations: (1) energy can drive self-sustained oscillations, (2) the energetic cost of spiking modulates the degree and type of oscillations, (3) harmonics emerge with frequencies determined by energy parameters, and (4) varying energetic costs have non-linear effects on energy consumption and firing rates. Conclusions: Models of neuron function which attempt biological realism may benefit from including energy constraints. Further, we assert that observed oscillatory effects of energy limitations exist in networks of many kinds, and that these findings generalize to abstract graphs and technological applications.
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Affiliation(s)
- Javier Burroni
- Biologically Inspired Neural and Dynamical Systems Laboratory, College of Information and Computer Sciences, University of Massachusetts Amherst, MA, USA
| | - P Taylor
- Biologically Inspired Neural and Dynamical Systems Laboratory, College of Information and Computer Sciences, University of MassachusettsAmherst, MA, USA; Neuroscience and Behavior Program, University of MassachusettsAmherst, MA, USA
| | - Cassian Corey
- Biologically Inspired Neural and Dynamical Systems Laboratory, College of Information and Computer Sciences, University of Massachusetts Amherst, MA, USA
| | - Tengiz Vachnadze
- Biologically Inspired Neural and Dynamical Systems Laboratory, College of Information and Computer Sciences, University of Massachusetts Amherst, MA, USA
| | - Hava T Siegelmann
- Biologically Inspired Neural and Dynamical Systems Laboratory, College of Information and Computer Sciences, University of MassachusettsAmherst, MA, USA; Neuroscience and Behavior Program, University of MassachusettsAmherst, MA, USA
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11
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Lin AL, Rothman DL. What have novel imaging techniques revealed about metabolism in the aging brain? FUTURE NEUROLOGY 2014; 9:341-354. [PMID: 25214817 DOI: 10.2217/fnl.14.13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Brain metabolism declines with age and do so in an accelerated manner in neurodegenerative disorders. Noninvasive neuroimaging techniques have played an important role to identify the metabolic biomarkers in aging brain. Particularly, PET with fluorine-18 (18F)-labeled 2-fluoro-2-deoxy-d-glucose tracer and proton magnetic resonance spectroscopy (MRS) have been widely used to monitor changes in brain metabolism over time, identify the risk for Alzheimer's disease (AD) and predict the conversion from mild cognitive impairment to AD. Novel techniques, including PET carbon-11 Pittsburgh compound B, carbon-13 and phosphorus-31 MRS, have also been introduced to determine Aβ plaques deposition, mitochondrial functions and brain bioenergetics in aging brain and neurodegenerative disorders. Here, we introduce the basic principle of the imaging techniques, review the findings from 2-fluoro-2-deoxy-d-glucose-PET, Pittsburgh compound B PET, proton, carbon-13 and phosphorus-31 MRS on changes in metabolism in normal aging brain, mild cognitive impairment and AD, and discuss the potential of neuroimaging to identify effective interventions and treatment efficacy for neurodegenerative disorders.
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Affiliation(s)
- Ai-Ling Lin
- Sanders-Brown Center on Aging, Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Diagnostic Radiology & Biomedical Engineering, Yale University, New Haven, CT, USA
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12
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Guerrini R, Scerrati M, Rubboli G, Esposito V, Colicchio G, Cossu M, Marras CE, Tassi L, Tinuper P, Paola Canevini M, Quarato P, Giordano F, Granata T, Villani F, Giulioni M, Scarpa P, Barbieri V, Bottini G, Del Sole A, Vatti G, Spreafico R, Lo Russo G. Overview of presurgical assessment and surgical treatment of epilepsy from the Italian League Against Epilepsy. Epilepsia 2013; 54 Suppl 7:35-48. [DOI: 10.1111/epi.12308] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Renzo Guerrini
- Pediatric Neurology Unit and Laboratories; Children's Hospital A. Meyer-University of Florence; Florence Italy
| | - Massimo Scerrati
- Neurosurgery; University Hospital - Polytechnic University of Marche; Ancona Italy
| | - Guido Rubboli
- IRCCS Institute of Neurological Sciences; Bellaria Hospital; Bologna Italy
- Danish Epilepsy Center; Epilepsy Hospital, Dianalund Denmark
| | - Vincenzo Esposito
- Neurosurgery; I.R.C.C.S. Neuromed; Pozzilli (IS) Italy
- Department of Neurology and Psychiatry; Sapienza University of Rome; Rome Italy
| | | | - Massimo Cossu
- C. Munari Epilepsy Surgery Center; Niguarda Hospital; Milan Italy
| | - Carlo Efisio Marras
- Neurosurgery Unit; Department of Neuroscience e Neurorehabilitation; Bambino Gesù Children Hospital; Rome Italy
| | - Laura Tassi
- C. Munari Epilepsy Surgery Center; Niguarda Hospital; Milan Italy
| | - Paolo Tinuper
- Neurological Clinic; Bellaria Hospital IRCCS Institute of Neurological Sciences of Bologna and Department of Biomedical and Neuromotor Sciences; University of Bologna; Bologna Italy
| | - Maria Paola Canevini
- Epilepsy Center; San Paolo Hospital and Department of Health Sciences; University of Milan; Milan Italy
| | - Pierpaolo Quarato
- Epilepsy Surgery Unit; Department of Neurological Sciences; IRCCS “NEUROMED”; Pozzilli (IS) Italy
| | - Flavio Giordano
- Pediatric Neurosurgery Unit; Children's Hospital Meyer-University of Florence; Florence Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience; Carlo Besta Neurological Institute; Milan Italy
| | - Flavio Villani
- Clinical Epileptology and Experimental Neurophysiology Unit; Carlo Besta Neurological Institute; Milan Italy
| | - Marco Giulioni
- Division of Neurosurgery; IRCCS Institute of Neurological Sciences of Bologna; Bellaria Hospital; Bologna Italy
| | - Pina Scarpa
- Cognitive Neuropsychology Centre; Niguarda Hospital; Milan Italy
| | - Valentina Barbieri
- Psychiatric Branch; Department of Medicine, Surgery and Dentistry; University of Milan and San Paolo Hospital; Milan Italy
| | - Gabriella Bottini
- Cognitive Neuropsychology Centre; Niguarda Hospital; Milan Italy
- Department of Psychology; University of Pavia; Pavia Italy
| | - Angelo Del Sole
- Department of Diagnostic Services; Unit of Nuclear Medicine; San Paolo Hospital and Department of Health Sciences; University of Milan; Milan Italy
| | - Giampaolo Vatti
- Department of Neurological and Sensorial Sciences; University of Siena; Siena Italy
| | - Roberto Spreafico
- Clinical Epileptology and Experimental Neurophysiology Unit; Carlo Besta Neurological Institute; Milan Italy
| | - Giorgio Lo Russo
- C. Munari Epilepsy Surgery Center; Niguarda Hospital; Milan Italy
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Greer DM, Scripko PD, Wu O, Edlow BL, Bartscher J, Sims JR, Camargo EEC, Singhal AB, Furie KL. Hippocampal magnetic resonance imaging abnormalities in cardiac arrest are associated with poor outcome. J Stroke Cerebrovasc Dis 2012; 22:899-905. [PMID: 22995378 DOI: 10.1016/j.jstrokecerebrovasdis.2012.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 07/01/2012] [Accepted: 08/16/2012] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The role of neuroimaging in assessing prognosis in comatose cardiac survivors appears promising, but little is known regarding the import of particular spatial patterns. We report a specific spatial imaging abnormality on magnetic resonance imaging (MRI) that portends a poor prognosis: bilateral hippocampal hyperintensities on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences. METHODS Eighty sequential comatose cardiac arrest patients underwent MRI scans. Qualitative and quantitative regional analyses were performed. Patients were categorized as HIPPO(+) (n = 18) or HIPPO(-) (n = 62) based on whether they had bilateral hippocampal hyperintensities. Poor outcome was defined by a modified Rankin Scale (mRS) score ≥4 at 6 months. RESULTS Patients with bilateral hippocampal abnormalities had a higher frequency of poor outcome (P = .032). HIPPO(+) patients suffered more severe cerebral injury, with lower whole brain apparent diffusion coefficient values (P = .043) and a greater number of affected regions on DWI (P = .001) and FLAIR (P = .001) than HIPPO(-) patients. The hippocampal approach was 100% specific for a poor prognosis; only 1 patient survived and remained in a vegetative state. CONCLUSIONS Bilateral hippocampal hyperintensities on MRI may be a specific imaging finding that is indicative of poor prognosis in patients who suffer global hypoxic-ischemic injury. More research on the prognostic significance of this and similar neuroimaging patterns is indicated.
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Affiliation(s)
- David M Greer
- Department of Neurology at Yale University School of Medicine, New Haven, Connecticut; Department of Neurology at Massachusetts General Hospital, Boston.
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Dietrich A, Audiffren M. The reticular-activating hypofrontality (RAH) model of acute exercise. Neurosci Biobehav Rev 2011; 35:1305-25. [PMID: 21315758 DOI: 10.1016/j.neubiorev.2011.02.001] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 02/02/2011] [Accepted: 02/03/2011] [Indexed: 11/16/2022]
Abstract
We present here a comprehensive, neurocognitive model to account for the psychological consequences of acute exercise. There is a substantial amount of disparate research and the proposed mechanistic explanation meaningfully integrates this body of brain and behavioral data into a single, unified model. The model's central feature is a cascading, two-step process. First, exercise engages arousal mechanisms in the reticular-activating system. This activation process, which involves a number of neurotransmitter systems, has several interrelated effects on cognition and emotion but, in general, has evolved to facilitate implicit information processing. Second, exercise disengages the higher-order functions of the prefrontal cortex. This deactivation process, which is caused in part by resource limitations, also has several interrelated effects but, in general, has evolved to keep the inefficient explicit system and unhelpful emotional processes from compromising the implicit system's functioning when optimal motor execution is needed most. In this article, we review evidence in support of this reticular-activating hypofrontality (RAH) model of acute exercise and place it into a larger evolutionary context.
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Affiliation(s)
- Arne Dietrich
- Department of Social and Behavioral Sciences, American University of Beirut, Beirut 1107-2020, Lebanon.
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15
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Cunnane S, Nugent S, Roy M, Courchesne-Loyer A, Croteau E, Tremblay S, Castellano A, Pifferi F, Bocti C, Paquet N, Begdouri H, Bentourkia M, Turcotte E, Allard M, Barberger-Gateau P, Fulop T, Rapoport SI. Brain fuel metabolism, aging, and Alzheimer's disease. Nutrition 2011; 27:3-20. [PMID: 21035308 PMCID: PMC3478067 DOI: 10.1016/j.nut.2010.07.021] [Citation(s) in RCA: 390] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Revised: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/14/2022]
Abstract
Lower brain glucose metabolism is present before the onset of clinically measurable cognitive decline in two groups of people at risk of Alzheimer's disease--carriers of apolipoprotein E4, and in those with a maternal family history of AD. Supported by emerging evidence from in vitro and animal studies, these reports suggest that brain hypometabolism may precede and therefore contribute to the neuropathologic cascade leading to cognitive decline in AD. The reason brain hypometabolism develops is unclear but may include defects in brain glucose transport, disrupted glycolysis, and/or impaired mitochondrial function. Methodologic issues presently preclude knowing with certainty whether or not aging in the absence of cognitive impairment is necessarily associated with lower brain glucose metabolism. Nevertheless, aging appears to increase the risk of deteriorating systemic control of glucose utilization, which, in turn, may increase the risk of declining brain glucose uptake, at least in some brain regions. A contributing role of deteriorating glucose availability to or metabolism by the brain in AD does not exclude the opposite effect, i.e., that neurodegenerative processes in AD further decrease brain glucose metabolism because of reduced synaptic functionality and hence reduced energy needs, thereby completing a vicious cycle. Strategies to reduce the risk of AD by breaking this cycle should aim to (1) improve insulin sensitivity by improving systemic glucose utilization, or (2) bypass deteriorating brain glucose metabolism using approaches that safely induce mild, sustainable ketonemia.
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Affiliation(s)
- Stephen Cunnane
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Physiology and Biophysics, Université de Sherbrooke, Sherbrooke, QC, Canada.
| | - Scott Nugent
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Physiology and Biophysics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Maggie Roy
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Physiology and Biophysics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Alexandre Courchesne-Loyer
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Physiology and Biophysics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Etienne Croteau
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Sébastien Tremblay
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Alex Castellano
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - Christian Bocti
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Nancy Paquet
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Hadi Begdouri
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - M'hamed Bentourkia
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Turcotte
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Michèle Allard
- UMR CNRS 5231 and Ecole Pratique des Hautes Etudes, France
| | - Pascale Barberger-Gateau
- INSERM U897, Bordeaux F-33076, France; Université Victor Segalen Bordeaux 2, Bordeaux F-33076, France
| | - Tamas Fulop
- Research Center on Aging, Health and Social Services Center-Sherbrooke University Geriatrics Institute, Université de Sherbrooke, Sherbrooke, QC, Canada; Department of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Stanley I Rapoport
- Brain Physiology and Metabolism Section, National Institute of Aging, Bethesda, MD, USA
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Fuller S, Münch G, Steele M. Activated astrocytes: a therapeutic target in Alzheimer's disease? Expert Rev Neurother 2010; 9:1585-94. [PMID: 19903019 DOI: 10.1586/ern.09.111] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Astrocytes become activated in Alzheimer's disease, contributing to and reinforcing an inflammatory cascade. A large body of evidence suggests that by transforming from a basal to a reactive state, astrocytes neglect their neurosupportive functions, thus rendering neurons vulnerable to neurotoxins, including proinflammatory cytokines and reactive oxygen species. This review highlights three important astrocytic functions that may be impaired in neurodegenerative diseases such as Alzheimer's disease. These are: the uptake of glucose and release of lactate; the uptake of glutamate and release of glutamine; and the uptake of glutathione precursors and release of glutathione. Astrocytes could become promising targets of therapeutic intervention for Alzheimer's disease, if these compromised functions can be normalized with pharmacological agents that are specifically designed to return astrocytes to a quiescent phenotype or to supplement any factors that activated astrocytes fail to produce.
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Affiliation(s)
- Stacey Fuller
- Department of Pharmacology, School of Medicine, University of Western Sydney, Campbelltown, NSW 1797, Australia.
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Goldstein G, Panchalingam K, McClure RJ, Stanley JA, Calhoun VD, Pearlson GD, Pettegrew JW. Molecular neurodevelopment: an in vivo 31P-1H MRSI study. J Int Neuropsychol Soc 2009; 15:671-83. [PMID: 19674503 PMCID: PMC2773163 DOI: 10.1017/s1355617709990233] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Synaptic development and elimination are normal neurodevelopmental processes, which if altered could contribute to various neuropsychiatric disorders. 31P-1H magnetic resonance spectroscopic imaging (MRSI) and structural magnetic resonance imaging (MRI) exams were conducted on 105 healthy children ages 6-18 years old to identify neuromolecular indices of synaptic development and elimination. Over the age range studied, age-related changes in high-energy phosphate (phosphocreatine), membrane phospholipid metabolism (precursors and breakdown products), and percent gray matter volume were found. These neuromolecular and structural indices of synaptic development and elimination are associated with development of several cognitive domains. Monitoring of these molecular markers is essential for devising treatment strategies for neurodevelopmental disorders.
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Freemantle E, Vandal M, Tremblay Mercier J, Plourde M, Poirier J, Cunnane SC. Metabolic response to a ketogenic breakfast in the healthy elderly. J Nutr Health Aging 2009; 13:293-8. [PMID: 19300863 DOI: 10.1007/s12603-009-0026-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE To determine whether the metabolism of glucose or ketones differs in the healthy elderly compared to young or middle-aged adults during mild, short-term ketosis induced by a ketogenic breakfast. DESIGN AND PARTICIPANTS Healthy subjects in three age groups (23 +/- 1, 50 +/- 1 and 76 +/- 2 y old) were given a ketogenic meal and plasma beta -hydroxybutyrate, glucose, insulin, triacylglycerols, total cholesterol, non-esterified fatty acids and breath acetone were measured over the subsequent 6 h. Each subject completed the protocol twice in order to determine the oxidation of a tracer dose of both carbon-13 (13C) glucose and 13C-beta-hydroxybutyrate. The tracers were given separately in random order. Apolipoprotein E genotype was also determined in all subjects. RESULTS Plasma glucose decreased and beta-hydroxybutyrate, acetone and insulin increased similarly over 6 h in all three groups after the ketogenic meal. There was no significant change in cholesterol, triacylglycerols or non-esterified fatty acids over the 6 h. 13C-glucose and 13C-beta-hydroxybutyrate oxidation peaked at 2-3 h postdose for all age groups. Cumulative 13C-glucose oxidation over 24 h was significantly higher in the elderly but only versus the middle-aged group. There was no difference in cumulative 13C-beta-hydroxybutyrate oxidation between the three groups. Apolipoprotein E (epsilon 4) was associated with elevated fasting cholesterol but was unrelated to the other plasma metabolites. CONCLUSION Elderly people in relatively good health have a similar capacity to produce ketones and to oxidize 13C-beta-hydroxybutyrate as middle-aged or young adults, but oxidize 13C-glucose a little more rapidly than healthy middle-aged adults.
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Affiliation(s)
- E Freemantle
- Research Center on Aging, Health, and Social Services Center, Sherbrooke University Geriatrics Institute, 1036 Belvédère S., Sherbrooke, QC, Canada
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Dietrich A. Imaging the imagination: the trouble with motor imagery. Methods 2008; 45:319-24. [PMID: 18539161 DOI: 10.1016/j.ymeth.2008.04.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 04/24/2008] [Accepted: 04/25/2008] [Indexed: 12/01/2022] Open
Abstract
Sports and exercise psychology finds itself in a most unfortunate situation these days. While all other branches of the psychological sciences help themselves freely to the glitzy new toys of modern neuroscience--MRI and PET, mostly--exploring the neural underpinnings of whatever cognitive function they are interested in exploring, the sport sciences are left out of the fun for the simple reason that these imaging instruments preclude motion--the very thing then that is the subject of interest to them. There are several legitimate ways around this problem but the one that seems to be most popular is, I think, not--legitimate, that is. The basic idea, unduly sharpened here, is the following. Neuroimaging studies have shown that imagined and actual motion share the same neural substrates or, alternatively, imagining an action corresponds to a subliminal activation of the same brain areas required for its execution. It follows from this, the arguments runs, that motor imagery can be used as a proxy for real motor performance, et voilà, the sports sciences can go wild with all the snazzy brain imaging tools after all--just like everyone else. This notion is, I believe, misbegotten, a house of cards that threatens to cast a long shadow over the field. The present article, then, is, to be frank, intended to put a machete to this kind of thinking. It does this by exposing this conclusion to be based on an unholy marriage of selective data reporting and gross overgeneralization. The result is a wild goose chase fueled by wishful thinking.
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Affiliation(s)
- Arne Dietrich
- Department of Social and Behavioral Sciences, American University of Beirut, Lebanon.
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Kölker S, Sauer SW, Hoffmann GF, Müller I, Morath MA, Okun JG. Pathogenesis of CNS involvement in disorders of amino and organic acid metabolism. J Inherit Metab Dis 2008; 31:194-204. [PMID: 18392748 DOI: 10.1007/s10545-008-0823-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 02/12/2008] [Accepted: 02/14/2008] [Indexed: 12/21/2022]
Abstract
Inherited disorders of amino and organic acid metabolism have a high cumulative frequency, and despite heterogeneous aetiology and varying clinical presentation, the manifestation of neurological disease is common. It has been demonstrated for some of these diseases that accumulating pathological metabolites are directly involved in the manifestation of neurological disease. Various pathomechanisms have been suggested in different in vitro and in vivo models including an impairment of brain energy metabolism, an imbalance of excitatory and inhibitory neurotransmission, altered transport across the blood-brain barrier and between glial cells and neurons, impairment of myelination and disturbed neuronal efflux of metabolic water. This review summarizes recent knowledge on pathomechanisms involved in phenylketonuria, glutaric aciduria type I, succinic semialdehyde dehydrogenase deficiency and aspartoacylase deficiency with examples, highlighting general as well as disease-specific concepts and their putative impact on treatment.
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Affiliation(s)
- S Kölker
- Department of General Pediatrics, Division of Inherited Metabolic Disease, University Children’s Hospital Heidelberg, Heidelberg, Germany.
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21
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González-Pardo H, Conejo NM, Arias JL. Oxidative metabolism of limbic structures after acute administration of diazepam, alprazolam and zolpidem. Prog Neuropsychopharmacol Biol Psychiatry 2006; 30:1020-6. [PMID: 16647177 DOI: 10.1016/j.pnpbp.2006.03.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effects of acute administration of two benzodiazepines and a non-benzodiazepine hypnotic on behavior and brain metabolism were evaluated in rats. After testing the behavioral action of the benzodiazepines on the open field and the elevated plus-maze, the effects of the three drugs on neuronal metabolism of particular limbic regions were measured using cytochrome c oxidase (CO) histochemistry. Diazepam (5 mg/kg i.p.) and alprazolam (0.5 mg/kg i.p.) induced clear anxiolytic effects and a decrease in locomotion, whereas zolpidem (2 mg/kg i.p.) caused an intense hypnotic effect. The anxiolytic effects of alprazolam were distinguishable from diazepam due to the pharmacological and clinical profile of this triazolobenzodiazepine. CO activity decreased significantly in almost all the limbic regions evaluated after zolpidem administration. However, significant prominent decreases in CO activity were found after diazepam treatment in the medial mammillary nucleus, anteroventral thalamus, cingulate cortex, dentate gyrus and basolateral amygdala. Alprazolam caused similar decreases in CO activity, with the exception of the prelimbic and cingulate cortices, where significant increases were detected. In agreement with previous studies using other functional mapping techniques, our results indicate that particular benzodiazepines and non-benzodiazepine hypnotics induce selective changes in brain oxidative metabolism.
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Affiliation(s)
- Héctor González-Pardo
- Laboratorio de Neurociencias, Facultad de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, E-33003 Oviedo, Spain.
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Burke M, Bührle C. BOLD response during uncoupling of neuronal activity and CBF. Neuroimage 2006; 32:1-8. [PMID: 16677832 DOI: 10.1016/j.neuroimage.2006.03.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 02/27/2006] [Accepted: 03/16/2006] [Indexed: 11/22/2022] Open
Abstract
The widely used technique of functional magnetic resonance imaging (fMRI) based on the blood oxygenation level-dependent (BOLD) effect is a tool for the investigation of changes in local brain activity upon stimulation. The principle of measurement is based on the assumption that there is a strong coupling between changes in neural activity, metabolism, vascular response and oxygen extraction in the area under investigation. As fMRI is on the way to become a routine tool in clinical examinations, we wanted to investigate whether, generally and under a variety of conditions, there is a strong link between the BOLD signal and neural activity. For clinical and experimental application of the method, it is crucial, whether the absence of changes in BOLD signal intensity upon stimulation can always be interpreted as an absence of changes in brain activity. We approached this question by inhibiting the nitric oxide mediated 'neurovascular coupling' via application of 7 nitroindazole. Before and after inhibition of this neurovascular coupling, we acquired evoked potentials and performed fMRI during somatosensory stimulation in rats. Cerebral blood flow response as well as BOLD signal intensity changes following electrical stimulation were abolished within 10 min after application of 7 nitroindazole, whereas somatosensory-evoked potentials were only slightly affected but still clearly detectable. Even 1 h after injection of 7 nitroindazole, there was still remaining electrical activity. Thus, we observed an uncoupling between electrical, i.e., neural activity and the BOLD signal. According to our results, the absence of BOLD signal changes did not permit the conclusion that there was no neural activity in the area under investigation. Our findings are especially relevant for the clinical application of fMRI in patients suffering from cerebrovascular and other brain diseases.
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Affiliation(s)
- M Burke
- Faculty of Psychology, Section for Experimental and Biological Psychology, Philipps-Universität Marburg, Gutenbergstrasse 18, D-35032 Marburg, Germany.
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23
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Choi JK, Chen YI, Hamel E, Jenkins BG. Brain hemodynamic changes mediated by dopamine receptors: Role of the cerebral microvasculature in dopamine-mediated neurovascular coupling. Neuroimage 2006; 30:700-12. [PMID: 16459104 DOI: 10.1016/j.neuroimage.2005.10.029] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/30/2005] [Accepted: 10/14/2005] [Indexed: 11/27/2022] Open
Abstract
The coupling between neurotransmitter-induced changes in neuronal activity and the resultant hemodynamic response is central to the interpretation of neuroimaging techniques. In the present study, MRI experiments showed that dopamine transporter blockers such as cocaine and dopamine releasers such as amphetamine and D1 receptor agonists induced large positive increases in relative cerebral blood volume (rCBV) that were not sensitive to nitric oxide synthase inhibition. However, D1/D5 receptor antagonism with SCH-23390 prevented or blocked the hemodynamic response without any concomitant effect on dopamine release. Dopamine D2/D3 receptor agonists, in contrast, induced negative changes in rCBV in brain regions corresponding largely to those endowed with these receptors. D1 and D5 receptor mRNAs were expressed in microvessels of responsive brain areas, while D2 and D3 receptors were not consistently associated with the microvascular bed. D3 receptors had an astroglial localization. Together, these experiments show that direct effects of dopamine upon the vasculature cannot be ignored in measuring the hemodynamic coupling associated with dopaminergic drugs. These results further suggest that this coupling is partially mediated through D1/D5 receptors on the microvasculature leading to increased rCBV and through astroglial D3 receptors leading to decreased rCBV. These data provide additional support for the role of local post-synaptic events in neurovascular coupling and emphasize that the interpretation of fMRI signals exclusively in terms of neuronal activity may be incomplete.
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Affiliation(s)
- Ji-Kyung Choi
- MGH-NMR Center and Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Building 149 13th Street Charlestown, MA 02129, USA
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24
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Montero SA, Cadenas JL, Lemus M, Roces de Alvarez-Buylla E, Alvarez-Buylla R. Nitric oxide in brain glucose retention after carotid body receptors stimulation with cyanide in rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 580:293-300; discussion 351-9. [PMID: 16683734 DOI: 10.1007/0-387-31311-7_45] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Affiliation(s)
- S A Montero
- Centro Universitario de Investigaciones Biomedicas, Universidad de Colima, Colima, México
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25
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Hérard AS, Besret L, Dubois A, Dauguet J, Delzescaux T, Hantraye P, Bonvento G, Moya KL. siRNA targeted against amyloid precursor protein impairs synaptic activity in vivo. Neurobiol Aging 2005; 27:1740-50. [PMID: 16337035 DOI: 10.1016/j.neurobiolaging.2005.10.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 10/07/2005] [Accepted: 10/20/2005] [Indexed: 11/27/2022]
Abstract
The amyloid precursor protein (APP) plays a central role in Alzheimer's disease (AD) pathogenesis through its cleavage leading to the accumulation of the peptide betaA4. Diffusible oligomeric assemblies of amyloid beta peptide are thought to induce synaptic dysfunction, an early change in AD. We tested the hypothesis that a reduction in presynaptic APP could itself lead to a decrease in synaptic efficacy in vivo. Twenty-four hours after intraocular injection, siRNA targeted against APP accumulated in retinal cells and the APP in retinal terminals in the superior colliculus was significantly reduced. Surprisingly, the amyloid precursor-like protein 2 (APLP2) was reduced as well. Functional imaging experiments in rats during visual stimulation showed that knockdown of presynaptic APP/APLP2 significantly reduced the stimulation-induced glucose utilization in the superior colliculus. Our results suggest that perturbations in the amount of APP/APLP2 axonally transported to, and/or in their turnover in the nerve terminal alter synaptic function and could be a pathogenic mechanism in AD.
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Affiliation(s)
- A S Hérard
- CEA-CNRS URA 2210, Service Hospitalier Frédéric Joliot, 4, Place du Général Leclerc, F-91401 Orsay Cedex, France
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26
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Mehrabian Z, Liu LI, Fiskum G, Rapoport SI, Chandrasekaran K. Regulation of mitochondrial gene expression by energy demand in neural cells. J Neurochem 2005; 93:850-60. [PMID: 15857388 DOI: 10.1111/j.1471-4159.2005.03066.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mitochondrial DNA (mtDNA) encodes critical subunit proteins of the oxidative phosphorylation (OXPHOS) complex that generates ATP. This study tested the hypothesis that mitochondrial gene expression in neural cells is regulated by energy demand, as modified via stimulation of cellular sodium transport. Exposure of PC12S cells to the sodium ionophore monensin (250 nm) for 1-6 h caused a 13-60% decrease in cellular ATP (from 15 to 5 nmol per mg protein at 6 h). Levels of mitochondrial DNA-encoded mRNAs (mt-mRNAs) increased significantly (150%) within the first hour of exposure to monensin, and then decreased significantly (50%) at 3-4 h. Levels of mtDNA-encoded 12S rRNA and nuclear DNA-encoded OXPHOS subunit mRNAs were not significantly affected. Exposure of primary cerebellar neuronal cultures to the excitatory amino acid glutamate caused a similar rapid and significant increase followed by a significant decrease in cell mt-mRNA levels. The monensin-induced initial increase in mt-mRNA levels was abolished by pretreatment with actinomycin D or by reducing extracellular sodium ion concentration. The monensin-induced delayed reduction in mt-mRNA levels was accelerated in the presence of actinomycin D, and was accompanied by a 67% reduction in the half-life (from 3.6 to 1.2 h). Exposure of PC12S cells to 2-deoxy-d-glucose significantly decreased cellular ATP levels (from 14.2 to 7.1 nmol per mg protein at 8 h), and increased mt-mRNA levels. These results suggest a physiological transcriptional mechanism of regulation of mitochondrial gene expression by energy demand and a post-transcriptional regulation that is independent of energy status of the cell.
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Affiliation(s)
- Zara Mehrabian
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, 21201, USA
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27
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Novotny EJ, Fulbright RK, Pearl PL, Gibson KM, Rothman DL. Magnetic resonance spectroscopy of neurotransmitters in human brain. Ann Neurol 2003; 54 Suppl 6:S25-31. [PMID: 12891651 DOI: 10.1002/ana.10697] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magnetic resonance spectroscopy (MRS) is a noninvasive method that permits measurement of the concentration of specific biochemical compounds in the brain and other organ systems in precisely defined regions guided by MR imaging (MRI). Recently, MRS methods have been developed to measure specific neurotransmitters in the brain. More advanced MRS methods have been developed to measure the synthesis rates and turnover of specific neurotransmitters. These turnover rates can provide measures of brain metabolism similar to radioisotope techniques. Also, investigations of the relationship of brain metabolism and specific neurotransmitter systems are now possible using MRS. Here, we review the MRS techniques and studies of neurotransmitters in the human brain. A discussion of the potential use of these techniques in the context of certain pediatric neurotransmitter disorders will be presented.
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Affiliation(s)
- Edward J Novotny
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520-8064, USA.
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28
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Trübel HKF, Maciejewski PK, Farber JH, Hyder F. Brain temperature measured by 1H-NMR in conjunction with a lanthanide complex. J Appl Physiol (1985) 2003; 94:1641-9. [PMID: 12626478 DOI: 10.1152/japplphysiol.00841.2002] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In vivo data on temperature distributions in the intact brain are scarce, partly due to lack of noninvasive methods for the region of interest. NMR has been exploited for probing a variety of brain activities in vivo noninvasively within the region of interest. Here we report the use of a thulium-based thermometric sensor, infused through the blood, for monitoring absolute temperature in rat brain in vivo by (1)H-NMR and validated by direct temperature measurements with thermocouple wires. Because the (1)H chemical shifts also demonstrate pH sensitivity, detection of multiple resonances was used to measure both temperature and pH simultaneously with high sensitivity. Examination of blood plasma and cerebral spinal fluid samples removed from rats infused with the thermometric sensor suggests that the complex, despite its negative charge, crosses the blood-brain barrier to enter the extracellular milieu. In the future, the thulium-based thermometric sensor may be used for monitoring temperature (and pH) distributions throughout the entire brain, examining response to therapy and evaluating changes induced by alterations in neuronal activity.
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Affiliation(s)
- Hubert K F Trübel
- Departments of Pediatrics, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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29
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Pettegrew JW, Klunk WE, Panchalingam K, McClure RJ, Stanley JA. Molecular insights into neurodevelopmental and neurodegenerative diseases. Brain Res Bull 2000; 53:455-69. [PMID: 11137004 DOI: 10.1016/s0361-9230(00)00376-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Magnetic resonance spectroscopy (MRS) is a non-invasive physical technique that is routinely used to determine the quantity and structure of organic molecules in solution. Technical advances that have expanded the usefulness of this technique include: (1) high resolution MRS to identify and quantify individual molecules present in complex mixtures of tissue extracts; (2) in vivo MRS techniques to non-invasively monitor metabolites in humans; (3) structure determination of proteins of moderate size; and (4) improved structure characterization of solids and liquid crystals, such as the detection of phase changes in membranes. The focus of this review is on the first two technical advances mentioned above. The strengths of MRS as a research tool to investigate molecular alterations in disease states include ease of sample preparation, minimum sample manipulation, avoidance of the preparation of derivatives, and the ability to analyze an unfractionated sample. The strengths of MRS in the clinic are its ability to measure neuronal metabolite levels non-invasively in humans and its potential for disease diagnosis, monitoring disease progression, and assessing the efficacy of experimental therapies.
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Affiliation(s)
- J W Pettegrew
- Department of Psychiatry, School of Medicine, Neurophysics Laboratory, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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30
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Abstract
Technologic advances in functional brain imaging have provided exciting and informative insights into the functional neuroanatomy and neurochemistry of schizophrenia. Using MR spectroscopy, it has been possible to examine in vivo brain metabolism and to relate observed changes to physiological processes occurring at a cellular level. Positron emission tomography and single photon emission computed tomography have revealed disturbances of cerebral blood flow and glucose metabolism in patients with schizophrenia. More recently, these tools have also proved most useful in studying the relative receptor occupancy of typical and atypical antipsychotic medications.
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Affiliation(s)
- R J McClure
- Department of Psychiatry, University of Pittsburgh Medical Center, Pennsylvania, USA
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31
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Pettegrew JW, Klunk WE, Panchalingam K, McClure RJ, Stanley JA. Magnetic resonance spectroscopic changes in Alzheimer's disease. Ann N Y Acad Sci 1997; 826:282-306. [PMID: 9329700 DOI: 10.1111/j.1749-6632.1997.tb48480.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In vitro and in vivo 31P magnetic resonance (MR) spectroscopy studies of Alzheimer's disease (AD) brain have revealed alterations in membrane phospholipid metabolism and high-energy phosphate metabolism. Mildly demented AD patients compared with control subjects have increased levels of phosphomonoesters, decreased levels of phosphocreatine and probably adenosine diphosphate and an increased oxidative metabolic rate. As the dementia worsens, levels of phosphomonoesters decrease and levels of phosphocreatine and adenosine di-phosphate increase. The changes in oxidative metabolic rate suggest that the AD brain is under energetic stress. The phosphomonoester findings support our in vitro findings and implicate basic defects in membrane metabolism in AD brain. MR spectroscopy provides new diagnostic insights and a noninvasive method to follow the progression of the disease and the metabolic response to therapeutic interventions.
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Affiliation(s)
- J W Pettegrew
- Department of Psychiatry, University of Pittsburgh, Pennsylvania 15213, USA
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32
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Kirstein CL, Philpot RM, Dark T. Fetal alcohol syndrome: early olfactory learning as a model system to study neurobehavioral deficits. Int J Neurosci 1997; 89:119-32. [PMID: 9134450 DOI: 10.3109/00207459708988467] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The goal of basic research examining the deficits underlying fetal alcohol syndrome is to develop an animal model which allows investigation and assessment of the neural and cognitive impairments resulting from prenatal alcohol exposure. The following review focuses on animal models and their relationship to human deficits following prenatal alcohol exposure. In addition, this review examines a unique, well-established model system which may permit an increased understanding of the role of alcohol on the developing brain and cognitive behavior. Specifically, large metabolic, neurochemical, neuropharmacological, morphological and neurophysiological changes in young rats have been reported as a consequence of early olfactory preference conditioning, a form of learning that normally occurs during both human and rat development. This olfactory odor preference training paradigm can be used to assess changes in learning as well as the neural substrates underlying this learning. Olfactory preference training has been used to examine: 1) learning, as demonstrated by a behavioral preference for an odor previously paired with stimulation which mimics maternal care; 2) metabolism, by measuring 2-deoxyglucose uptake and distribution in response to the trained odor; 3) neurotransmitter levels, by using in vivo microdialysis, to examine changes in neurotransmitter levels in the olfactory bulb in response to a trained odor. Using in vivo microdialysis enables measurement of both baseline responsiveness of alcohol-exposed pups as well as learned responses at several different developmental ages. The established neural features of this olfactory model include an increase in behavioral preference for a trained odor, increases in 2-DG uptake in specific foci within the olfactory bulb in response to the odor, and increases in dopamine in response to olfactory preference training stimuli, as well as conditioned increases in norepinephrine following olfactory preference training. Using these known behavioral, metabolic and neurochemical indices in control pups allows identification of some of the neurotransmitter systems involved in deficits and the neurobiological basis for impairments induced by prenatal alcohol exposure.
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Affiliation(s)
- C L Kirstein
- Department of Psychology, University of South Florida, Tampa 33620, USA
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33
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Abstract
In exercise, little is known about local cerebral glucose utilization (LCGU), which is an index of functional neurogenic activity. We measured LCGU in resting and running (approximately 85% of maximum O2 uptake) rats (n = 7 in both groups) previously equipped with a tail artery catheter. LCGU was measured quantitatively from 2-deoxy-D-[1-14C]glucose autoradiographs. During exercise, total cerebral glucose utilization (TCGU) increased by 38% (p < 0.005). LCGU increased (p < 0.05) in areas involved in motor function (motor cortex 39%, cerebellum approximately 110%, basal ganglia approximately 30%, substantia nigra approximately 37%, and in the following nuclei: subthalamic 47%, posterior hypothalamic 74%, red 61%, ambiguous 43%, pontine 61%), areas involved in sensory function (somatosensory 27%, auditory 32%, and visual cortex 42%, thalamus approximately 75%, and in the following nuclei: Darkschewitsch 22%, cochlear 51%, vestibular 30%, superior olive 23%, cuneate 115%), areas involved in autonomic function (dorsal raphe nucleus 30%, and areas in the hypothalamus approximately 35%, amygdala approximately 35%, and hippocampus 29%), and in white matter of the corpus callosum (36%) and cerebellum (52%). LCGU did not change with exercise in prefrontal and frontal cortex, cingulum, inferior olive, nucleus of solitary tract and median raphe, lateral septal and interpenduncular nuclei, or in areas of the hippocampus, amygdala, and hypothalamus. Glucose utilization did not decrease during exercise in any of the studied cerebral regions. In summary, heavy dynamic exercise increases TCGU and evokes marked differential changes in LCGU. The findings provide clues to the cerebral areas that participate in the large motor, sensory, and autonomic adaptation occurring in exercise.
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Affiliation(s)
- J Vissing
- Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark
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34
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Pettegrew JW, Klunk WE, Panchalingam K, Kanfer JN, McClure RJ. Clinical and neurochemical effects of acetyl-L-carnitine in Alzheimer's disease. Neurobiol Aging 1995; 16:1-4. [PMID: 7723928 DOI: 10.1016/0197-4580(95)80001-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In a double-blind, placebo study, acetyl-L-carnitine was administered to 7 probable Alzheimer's disease patients who were then compared by clinical and 31P magnetic resonance spectroscopic measures to 5 placebo-treated probable AD patients and 21 age-matched healthy controls over the course of 1 year. Compared to AD patients on placebo, acetyl-L-carnitine-treated patients showed significantly less deterioration in their Mini-Mental Status and Alzheimer's Disease Assessment Scale test scores. Furthermore, the decrease in phosphomonoester levels observed in both the acetyl-L-carnitine and placebo AD groups at entry was normalized in the acetyl-L-carnitine-treated but not in the placebo-treated patients. Similar normalization of high-energy phosphate levels was observed in the acetyl-L-carnitine-treated but not in the placebo-treated patients. This is the first direct in vivo demonstration of a beneficial effect of a drug on both clinical and CNS neurochemical parameters in AD.
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Affiliation(s)
- J W Pettegrew
- Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh, School of Medicine, PA 15213, USA
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