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Measuring Cortical Connectivity in Alzheimer's Disease as a Brain Neural Network Pathology: Toward Clinical Applications. J Int Neuropsychol Soc 2016; 22:138-63. [PMID: 26888613 DOI: 10.1017/s1355617715000995] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES The objective was to review the literature on diffusion tensor imaging as well as resting-state functional magnetic resonance imaging and electroencephalography (EEG) to unveil neuroanatomical and neurophysiological substrates of Alzheimer's disease (AD) as a brain neural network pathology affecting structural and functional cortical connectivity underlying human cognition. METHODS We reviewed papers registered in PubMed and other scientific repositories on the use of these techniques in amnesic mild cognitive impairment (MCI) and clinically mild AD dementia patients compared to cognitively intact elderly individuals (Controls). RESULTS Hundreds of peer-reviewed (cross-sectional and longitudinal) papers have shown in patients with MCI and mild AD compared to Controls (1) impairment of callosal (splenium), thalamic, and anterior-posterior white matter bundles; (2) reduced correlation of resting state blood oxygen level-dependent activity across several intrinsic brain circuits including default mode and attention-related networks; and (3) abnormal power and functional coupling of resting state cortical EEG rhythms. Clinical applications of these measures are still limited. CONCLUSIONS Structural and functional (in vivo) cortical connectivity measures represent a reliable marker of cerebral reserve capacity and should be used to predict and monitor the evolution of AD and its relative impact on cognitive domains in pre-clinical, prodromal, and dementia stages of AD.
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Heinzel S, Metzger FG, Ehlis AC, Korell R, Alboji A, Haeussinger FB, Wurster I, Brockmann K, Suenkel U, Eschweiler GW, Maetzler W, Berg D, Fallgatter AJ. Age and Vascular Burden Determinants of Cortical Hemodynamics Underlying Verbal Fluency. PLoS One 2015; 10:e0138863. [PMID: 26394050 PMCID: PMC4578891 DOI: 10.1371/journal.pone.0138863] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/04/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Aging processes and several vascular burden factors have been shown to increase the risk of dementia including Alzheimer's disease. While pathological alterations in dementia precede diagnosis by many years, reorganization of brain processing might temporarily delay cognitive decline. We hypothesized that in healthy elderly individuals both age-related neural and vascular factors known to be related to the development of dementia impact functional cortical hemodynamics during increased cognitive demands. METHODS Vascular burden factors and cortical functional hemodynamics during verbal fluency were assessed in 1052 non-demented elderly individuals (51 to 83 years; cross-sectional data of the longitudinal TREND study) using functional near-infrared spectroscopy (fNIRS). The prediction of functional hemodynamic responses by age in multiple regressions and the impact of single and cumulative vascular burden factors including hypertension, diabetes, obesity, smoking and atherosclerosis were investigated. RESULTS Replicating and extending previous findings we could show that increasing age predicted functional hemodynamics to be increased in right prefrontal and bilateral parietal cortex, and decreased in bilateral inferior frontal junction during phonological fluency. Cumulative vascular burden factors, with hypertension in particular, decreased left inferior frontal junction hemodynamic responses during phonological fluency. However, age and vascular burden factors showed no statistical interaction on functional hemodynamics. CONCLUSION Based on these findings, one might hypothesize that increased fronto-parietal processing may represent age-related compensatory reorganization during increased cognitive demands. Vascular burden factors, such as hypertension, may contribute to regional cerebral hypoperfusion. These neural and vascular hemodynamic determinants should be investigated longitudinally and combined with other markers to advance the prediction of future cognitive decline and dementia.
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Affiliation(s)
- Sebastian Heinzel
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tuebingen, Tuebingen, Germany
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
- * E-mail:
| | - Florian G. Metzger
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
- Geriatric Center, University Hospital Tübingen, Tübingen, Germany
| | - Ann-Christine Ehlis
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
| | - Robert Korell
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
| | - Ahmed Alboji
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
| | | | - Isabel Wurster
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tuebingen, Tuebingen, Germany
| | - Kathrin Brockmann
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tuebingen, Tuebingen, Germany
| | - Ulrike Suenkel
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tuebingen, Tuebingen, Germany
| | - Gerhard W. Eschweiler
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
- Geriatric Center, University Hospital Tübingen, Tübingen, Germany
| | - Walter Maetzler
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tuebingen, Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
| | - Daniela Berg
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tuebingen, Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
| | - Andreas J. Fallgatter
- Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany
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Nugent S, Castellano CA, Bocti C, Dionne I, Fulop T, Cunnane SC. Relationship of metabolic and endocrine parameters to brain glucose metabolism in older adults: do cognitively-normal older adults have a particular metabolic phenotype? Biogerontology 2015; 17:241-55. [DOI: 10.1007/s10522-015-9595-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/25/2015] [Indexed: 01/13/2023]
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Metabolic connectivity as index of verbal working memory. J Cereb Blood Flow Metab 2015; 35:1122-6. [PMID: 25785830 PMCID: PMC4640275 DOI: 10.1038/jcbfm.2015.40] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/20/2015] [Accepted: 02/16/2015] [Indexed: 11/08/2022]
Abstract
Positron emission tomography (PET) data are commonly analyzed in terms of regional intensity, while covariant information is not taken into account. Here, we searched for network correlates of healthy cognitive function in resting state PET data. PET with [(18)F]-fluorodeoxyglucose and a test of verbal working memory (WM) were administered to 35 young healthy adults. Metabolic connectivity was modeled at a group level using sparse inverse covariance estimation. Among 13 WM-relevant Brodmann areas (BAs), 6 appeared to be robustly connected. Connectivity within this network was significantly stronger in subjects with above-median WM performance. In respect to regional intensity, i.e., metabolism, no difference between groups was found. The results encourage examination of covariant patterns in FDG-PET data from non-neurodegenerative populations.
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Swerdlow RH. Bioenergetic medicine. Br J Pharmacol 2014; 171:1854-69. [PMID: 24004341 DOI: 10.1111/bph.12394] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 08/17/2013] [Accepted: 08/22/2013] [Indexed: 12/12/2022] Open
Abstract
Here we discuss a specific therapeutic strategy we call 'bioenergetic medicine'. Bioenergetic medicine refers to the manipulation of bioenergetic fluxes to positively affect health. Bioenergetic medicine approaches rely heavily on the law of mass action, and impact systems that monitor and respond to the manipulated flux. Since classically defined energy metabolism pathways intersect and intertwine, targeting one flux also tends to change other fluxes, which complicates treatment design. Such indirect effects, fortunately, are to some extent predictable, and from a therapeutic perspective may also be desirable. Bioenergetic medicine-based interventions already exist for some diseases, and because bioenergetic medicine interventions are presently feasible, new approaches to treat certain conditions, including some neurodegenerative conditions and cancers, are beginning to transition from the laboratory to the clinic.
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Affiliation(s)
- Russell H Swerdlow
- Departments of Neurology, Molecular and Integrative Physiology, Biochemistry and Molecular Biology, University of Kansas School of Medicine, Kansas City, KS, USA; Alzheimer's Disease Center, University of Kansas Medical Center, Fairway, KS, USA
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Wilkins HM, Carl SM, Greenlief ACS, Festoff BW, Swerdlow RH. Bioenergetic dysfunction and inflammation in Alzheimer's disease: a possible connection. Front Aging Neurosci 2014; 6:311. [PMID: 25426068 PMCID: PMC4226164 DOI: 10.3389/fnagi.2014.00311] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/23/2014] [Indexed: 11/29/2022] Open
Abstract
Inflammation is observed in Alzheimer’s disease (AD) subject brains. Inflammation-relevant genes are increasingly implicated in AD genetic studies, and inflammatory cytokines to some extent even function as peripheral biomarkers. What underlies AD inflammation is unclear, but no “foreign” agent has been implicated. This suggests that internally produced damage-associated molecular pattern (DAMPs) molecules may drive inflammation in AD. A more complete characterization and understanding of AD-relevant DAMPs could advance our understanding of AD and suggest novel therapeutic strategies. In this review, we consider the possibility that mitochondria, intracellular organelles that resemble bacteria in many ways, trigger and maintain chronic inflammation in AD subjects. Data supporting the possible nexus between AD-associated bioenergetic dysfunction are discussed.
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Affiliation(s)
- Heather M Wilkins
- Department of Neurology, University of Kansas Medical Center , Kansas City, KS , USA ; University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center , Kansas City, KS , USA
| | - Steven M Carl
- University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center , Kansas City, KS , USA
| | - Alison C S Greenlief
- University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center , Kansas City, KS , USA
| | - Barry W Festoff
- Department of Neurology, University of Kansas Medical Center , Kansas City, KS , USA ; Department of Pharmacology, University of Kansas Medical Center , Kansas City, KS , USA ; Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, KS , USA ; pHLOGISTIX Neurodiagnostics , Lenexa, KS , USA
| | - Russell H Swerdlow
- Department of Neurology, University of Kansas Medical Center , Kansas City, KS , USA ; University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center , Kansas City, KS , USA ; Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, KS , USA ; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center , Kansas City, KS , USA
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Vidal-Piñeiro D, Valls-Pedret C, Fernández-Cabello S, Arenaza-Urquijo EM, Sala-Llonch R, Solana E, Bargalló N, Junqué C, Ros E, Bartrés-Faz D. Decreased Default Mode Network connectivity correlates with age-associated structural and cognitive changes. Front Aging Neurosci 2014; 6:256. [PMID: 25309433 PMCID: PMC4174767 DOI: 10.3389/fnagi.2014.00256] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 09/09/2014] [Indexed: 11/13/2022] Open
Abstract
Ageing entails cognitive and motor decline as well as brain changes such as loss of gray (GM) and white matter (WM) integrity, neurovascular and functional connectivity alterations. Regarding connectivity, reduced resting-state fMRI connectivity between anterior and posterior nodes of the Default Mode Network (DMN) relates to cognitive function and has been postulated to be a hallmark of ageing. However, the relationship between age-related connectivity changes and other neuroimaging-based measures in ageing is fragmentarily investigated. In a sample of 116 healthy elders we aimed to study the relationship between antero-posterior DMN connectivity and measures of WM integrity, GM integrity and cerebral blood flow (CBF), assessed with an arterial spin labeling sequence. First, we replicated previous findings demonstrating DMN connectivity decreases in ageing and an association between antero-posterior DMN connectivity and memory scores. The results showed that the functional connectivity between posterior midline structures and the medial prefrontal cortex was related to measures of WM and GM integrity but not to CBF. Gray and WM correlates of anterio-posterior DMN connectivity included, but were not limited to, DMN areas and cingulum bundle. These results resembled patterns of age-related vulnerability which was studied by comparing the correlates of antero-posterior DMN with age-effect maps. These age-effect maps were obtained after performing an independent analysis with a second sample including both young and old subjects. We argue that antero-posterior connectivity might be a sensitive measure of brain ageing over the brain. By using a comprehensive approach, the results provide valuable knowledge that may shed further light on DMN connectivity dysfunctions in ageing.
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Affiliation(s)
- Didac Vidal-Piñeiro
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain
| | - Cinta Valls-Pedret
- Unitat de Lípids, Servei Endicronologia i Nutrició, Hospital Clínic Barcelona, Spain
| | - Sara Fernández-Cabello
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain
| | - Eider M Arenaza-Urquijo
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain ; Laboratoire de neuropsychologie, INSERM U1077 Caen, France
| | - Roser Sala-Llonch
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain ; Institut d'Investigacions Biomédiques August Pi i Sunyer (IDIBAPS) Barcelona, Spain
| | - Elisabeth Solana
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain
| | - Núria Bargalló
- Institut d'Investigacions Biomédiques August Pi i Sunyer (IDIBAPS) Barcelona, Spain ; Servei de Radiologia, Hospital Clínic de Barcelona Barcelona, Spain
| | - Carme Junqué
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain ; Institut d'Investigacions Biomédiques August Pi i Sunyer (IDIBAPS) Barcelona, Spain
| | - Emilio Ros
- Unitat de Lípids, Servei Endicronologia i Nutrició, Hospital Clínic Barcelona, Spain
| | - David Bartrés-Faz
- Departament de Psiquiatria i Psicobiologica Clinica, Facultat de Medicina, Universitat de Barcelona Barcelona, Spain ; Institut d'Investigacions Biomédiques August Pi i Sunyer (IDIBAPS) Barcelona, Spain
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Sundermann B, Olde lütke Beverborg M, Pfleiderer B. Toward literature-based feature selection for diagnostic classification: a meta-analysis of resting-state fMRI in depression. Front Hum Neurosci 2014; 8:692. [PMID: 25309382 PMCID: PMC4159995 DOI: 10.3389/fnhum.2014.00692] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/19/2014] [Indexed: 12/11/2022] Open
Abstract
Information derived from functional magnetic resonance imaging (fMRI) during wakeful rest has been introduced as a candidate diagnostic biomarker in unipolar major depressive disorder (MDD). Multiple reports of resting state fMRI in MDD describe group effects. Such prior knowledge can be adopted to pre-select potentially discriminating features for diagnostic classification models with the aim to improve diagnostic accuracy. Purpose of this analysis was to consolidate spatial information about alterations of spontaneous brain activity in MDD, primarily to serve as feature selection for multivariate pattern analysis techniques (MVPA). Thirty two studies were included in final analyses. Coordinates extracted from the original reports were assigned to two categories based on directionality of findings. Meta-analyses were calculated using the non-additive activation likelihood estimation approach with coordinates organized by subject group to account for non-independent samples. Converging evidence revealed a distributed pattern of brain regions with increased or decreased spontaneous activity in MDD. The most distinct finding was hyperactivity/hyperconnectivity presumably reflecting the interaction of cortical midline structures (posterior default mode network components including the precuneus and neighboring posterior cingulate cortices associated with self-referential processing and the subgenual anterior cingulate and neighboring medial frontal cortices) with lateral prefrontal areas related to externally-directed cognition. Other areas of hyperactivity/hyperconnectivity include the left lateral parietal cortex, right hippocampus and right cerebellum whereas hypoactivity/hypoconnectivity was observed mainly in the left temporal cortex, the insula, precuneus, superior frontal gyrus, lentiform nucleus and thalamus. Results are made available in two different data formats to be used as spatial hypotheses in future studies, particularly for diagnostic classification by MVPA.
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Affiliation(s)
- Benedikt Sundermann
- Department of Clinical Radiology, University Hospital MünsterMünster, Germany
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Swerdlow RH, Burns JM, Khan SM. The Alzheimer's disease mitochondrial cascade hypothesis: progress and perspectives. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:1219-31. [PMID: 24071439 PMCID: PMC3962811 DOI: 10.1016/j.bbadis.2013.09.010] [Citation(s) in RCA: 518] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/14/2013] [Accepted: 09/16/2013] [Indexed: 01/01/2023]
Abstract
Ten years ago we first proposed the Alzheimer's disease (AD) mitochondrial cascade hypothesis. This hypothesis maintains that gene inheritance defines an individual's baseline mitochondrial function; inherited and environmental factors determine rates at which mitochondrial function changes over time; and baseline mitochondrial function and mitochondrial change rates influence AD chronology. Our hypothesis unequivocally states in sporadic, late-onset AD, mitochondrial function affects amyloid precursor protein (APP) expression, APP processing, or beta amyloid (Aβ) accumulation and argues if an amyloid cascade truly exists, mitochondrial function triggers it. We now review the state of the mitochondrial cascade hypothesis, and discuss it in the context of recent AD biomarker studies, diagnostic criteria, and clinical trials. Our hypothesis predicts that biomarker changes reflect brain aging, new AD definitions clinically stage brain aging, and removing brain Aβ at any point will marginally impact cognitive trajectories. Our hypothesis, therefore, offers unique perspective into what sporadic, late-onset AD is and how to best treat it.
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Affiliation(s)
- Russell H Swerdlow
- Departments of Neurology and Molecular and Integrative Physiology, and the University of Kansas Alzheimer's Disease Center, University of Kansas School of Medicine, Kansas City, KS, USA; Department of Biochemistry and Molecular Biology, University of Kansas School of Medicine, Kansas City, KS, USA.
| | - Jeffrey M Burns
- Departments of Neurology and Molecular and Integrative Physiology, and the University of Kansas Alzheimer's Disease Center, University of Kansas School of Medicine, Kansas City, KS, USA
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Nugent S, Tremblay S, Chen KW, Ayutyanont N, Roontiva A, Castellano CA, Fortier M, Roy M, Courchesne-Loyer A, Bocti C, Lepage M, Turcotte E, Fulop T, Reiman EM, Cunnane SC. Brain glucose and acetoacetate metabolism: a comparison of young and older adults. Neurobiol Aging 2014; 35:1386-95. [DOI: 10.1016/j.neurobiolaging.2013.11.027] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 11/18/2013] [Accepted: 11/24/2013] [Indexed: 12/22/2022]
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Karbowski J. Constancy and trade-offs in the neuroanatomical and metabolic design of the cerebral cortex. Front Neural Circuits 2014; 8:9. [PMID: 24574975 PMCID: PMC3920482 DOI: 10.3389/fncir.2014.00009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 01/23/2014] [Indexed: 12/13/2022] Open
Abstract
Mammalian brains span about four orders of magnitude in cortical volume and have to operate in different environments that require diverse behavioral skills. Despite these geometric and behavioral diversities, the examination of cerebral cortex across species reveals that it contains a substantial number of conserved characteristics that are associated with neuroanatomy and metabolism, i.e., with neuronal connectivity and function. Some of these cortical constants or invariants have been known for a long time but not sufficiently appreciated, and others were only recently discovered. The focus of this review is to present the cortical invariants and discuss their role in the efficient information processing. Global conservation in neuroanatomy and metabolism, as well as their correlated regional and developmental variability suggest that these two parallel systems are mutually coupled. It is argued that energetic constraint on cortical organization can be strong if cerebral blood supplied is either below or above a certain level, and it is rather soft otherwise. Moreover, because maximization or minimization of parameters associated with cortical connectivity, function and cost often leads to conflicts in design, it is argued that the architecture of the cerebral cortex is a result of structural and functional compromises.
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Affiliation(s)
- Jan Karbowski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences Warsaw, Poland ; Department of Mathematics, Informatics and Mechanics, Institute of Applied Mathematics and Mechanics, University of Warsaw Warsaw, Poland ; Division of Biology Caltech, Pasadena, CA, USA
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Rettberg JR, Yao J, Brinton RD. Estrogen: a master regulator of bioenergetic systems in the brain and body. Front Neuroendocrinol 2014; 35:8-30. [PMID: 23994581 PMCID: PMC4024050 DOI: 10.1016/j.yfrne.2013.08.001] [Citation(s) in RCA: 322] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/09/2013] [Accepted: 08/10/2013] [Indexed: 01/12/2023]
Abstract
Estrogen is a fundamental regulator of the metabolic system of the female brain and body. Within the brain, estrogen regulates glucose transport, aerobic glycolysis, and mitochondrial function to generate ATP. In the body, estrogen protects against adiposity, insulin resistance, and type II diabetes, and regulates energy intake and expenditure. During menopause, decline in circulating estrogen is coincident with decline in brain bioenergetics and shift towards a metabolically compromised phenotype. Compensatory bioenergetic adaptations, or lack thereof, to estrogen loss could determine risk of late-onset Alzheimer's disease. Estrogen coordinates brain and body metabolism, such that peripheral metabolic state can indicate bioenergetic status of the brain. By generating biomarker profiles that encompass peripheral metabolic changes occurring with menopause, individual risk profiles for decreased brain bioenergetics and cognitive decline can be created. Biomarker profiles could identify women at risk while also serving as indicators of efficacy of hormone therapy or other preventative interventions.
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Affiliation(s)
- Jamaica R Rettberg
- Neuroscience Department, University of Southern California, Los Angeles, CA 90033, United States
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Roberta Diaz Brinton
- Neuroscience Department, University of Southern California, Los Angeles, CA 90033, United States; Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States.
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Lockau H, Jessen F, Fellgiebel A, Drzezga A. Structural and Functional Magnetic Resonance Imaging: Mild Cognitive Impairment and Alzheimer Disease. PET Clin 2013; 8:407-30. [PMID: 27156470 DOI: 10.1016/j.cpet.2013.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Magnetic resonance (MR) imaging is playing an increasingly pivotal role in the clinical management of dementia, including Alzheimer disease (AD). In addition to established MR imaging procedures, the introduction of advanced instrumentation such as 7-T MR imaging, as well as novel MR imaging sequences such as arterial spin labeling, MR spectroscopy, diffusion tensor imaging, and resting-state functional MR imaging, may open new pathways toward improved diagnosis of AD even in early stages of disease such as mild cognitive impairment (MCI). This article describes the typical findings of established and new MR imaging procedures in healthy aging, MCI, and AD.
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Affiliation(s)
- Hannah Lockau
- Department of Radiology, University Hospital Cologne, Kerpener Street 62, Cologne 50937, Germany
| | - Frank Jessen
- Department of Psychiatry, German Center for Neurodegenerative Diseases (DZNE), University of Bonn, Sigmund-Freud-Straße 25, Bonn 53105, Germany
| | - Andreas Fellgiebel
- Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Untere Zahlbacher Street 8, Mainz 55131, Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, University Hospital Cologne, Kerpener Street 62, Cologne 50937, Germany.
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Grashorn W, Sprenger C, Forkmann K, Wrobel N, Bingel U. Age-dependent decline of endogenous pain control: exploring the effect of expectation and depression. PLoS One 2013; 8:e75629. [PMID: 24086595 PMCID: PMC3785470 DOI: 10.1371/journal.pone.0075629] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/20/2013] [Indexed: 01/18/2023] Open
Abstract
Although chronic pain affects all age ranges, it is particularly common in the elderly. One potential explanation for the high prevalence of chronic pain in the older population is impaired functioning of the descending pain inhibitory system which can be studied in humans using conditioned pain modulation (CPM) paradigms. In this study we investigated (i) the influence of age on CPM and (ii) the role of expectations, depression and gender as potential modulating variables of an age-related change in CPM. 64 healthy volunteers of three different age groups (young = 20–40 years, middle-aged = 41–60 years, old = 61–80 years) were studied using a classical CPM paradigm that combined moderate heat pain stimuli to the right forearm as test stimuli (TS) and immersion of the contralateral foot into ice water as the conditioning stimulus (CS). The CPM response showed an age-dependent decline with strong CPM responses in young adults but no significant CPM responses in middle-aged and older adults. These age-related changes in CPM responses could not be explained by expectations of pain relief or depression. Furthermore, changes in CPM responses did not differ between men and women. Our results strongly support the notion of a genuine deterioration of descending pain inhibitory mechanisms with age.
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Affiliation(s)
- Wiebke Grashorn
- Department of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- * E-mail:
| | - Christian Sprenger
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Katarina Forkmann
- Department of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Nathalie Wrobel
- Department of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Ulrike Bingel
- Department of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
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Yakushev I, Chételat G, Fischer FU, Landeau B, Bastin C, Scheurich A, Perrotin A, Bahri MA, Drzezga A, Eustache F, Schreckenberger M, Fellgiebel A, Salmon E. Metabolic and structural connectivity within the default mode network relates to working memory performance in young healthy adults. Neuroimage 2013; 79:184-90. [PMID: 23631988 DOI: 10.1016/j.neuroimage.2013.04.069] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 03/24/2013] [Accepted: 04/16/2013] [Indexed: 02/08/2023] Open
Abstract
Studies of functional connectivity suggest that the default mode network (DMN) might be relevant for cognitive functions. Here, we examined metabolic and structural connectivity between major DMN nodes, the posterior cingulate (PCC) and medial prefrontal cortex (MPFC), in relation to normal working memory (WM). DMN was captured using independent component analysis of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) data from 35 young healthy adults (27.1 ± 5.1 years). Metabolic connectivity, a correlation between FDG uptake in PCC and MPFC, was examined in groups of subjects with (relative to median) low (n=18) and high (n=17) performance on digit span backward test as an index of verbal WM. In addition, fiber tractography based on PCC and MPFC nodes as way points was performed in a subset of subjects. FDG uptake in the DMN nodes did not differ between high and low performers. However, significantly (p=0.01) lower metabolic connectivity was found in the group of low performers. Furthermore, as compared to high performers, low performers showed lower density of the left superior cingulate bundle. Verbal WM performance is related to metabolic and structural connectivity within the DMN in young healthy adults. Metabolic connectivity as quantified with FDG-PET might be a sensitive marker of the normal variability in some cognitive functions.
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Affiliation(s)
- Igor Yakushev
- Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Mainz, Germany.
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