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Strýček O, Říha P, Kojan M, Řehák Z, Brázdil M. Metabolic connectivity as a predictor of surgical outcome in mesial temporal lobe epilepsy. Epilepsia Open 2024; 9:187-199. [PMID: 37881152 PMCID: PMC10839369 DOI: 10.1002/epi4.12853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023] Open
Abstract
OBJECTIVE The study investigated metabolic connectivity (MC) differences between patients with unilateral drug-resistant mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS) and healthy controls (HCs), based on [18 F]-fluorodeoxyglucose (FDG)-PET data. We focused on the MC changes dependent on the lateralization of the epileptogenic lobe and on correlations with postoperative outcomes. METHODS FDG-PET scans of 47 patients with unilateral MTLE with histopathologically proven HS and 25 HC were included in the study. All the patients underwent a standard anterior temporal lobectomy and were more than 2 years after the surgery. MC changes were compared between the two HS groups (left HS, right HS) and HC. Differences between the metabolic network of seizure-free and non-seizure-free patients after surgery were depicted afterward. Network changes were correlated with clinical characteristics. RESULTS The study showed widespread metabolic network changes in the HS patients as compared to HC. The changes were more extensive in the right HS than in the left HS. Unfavorable surgical outcomes were found in patients with decreased MC within the network including both the lesional and contralesional hippocampus, ipsilesional frontal operculum, and contralesional insula. Favorable outcomes correlated with decreased MC within the network involving both orbitofrontal cortices and the ipsilesional temporal lobe. SIGNIFICANCE There are major differences in the metabolic networks of left and right HS, with more extensive changes in right HS. The changes within the metabolic network could help predict surgical outcomes in patients with HS. MC may identify patients with potentially unfavorable outcomes and direct them to a more detailed presurgical evaluation. PLAIN LANGUAGE SUMMARY Metabolic connectivity is a promising method for metabolic network mapping. Metabolic networks in mesial temporal lobe epilepsy are dependent on lateralization of the epileptogenic lobe and could predict surgical outcomes.
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Affiliation(s)
- Ondřej Strýček
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of MedicineMasaryk University, Member of ERN‐EpiCAREBrnoCzech Republic
- Central European Institute of Technology (CEITEC)Masaryk UniversityBrnoCzech Republic
| | - Pavel Říha
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of MedicineMasaryk University, Member of ERN‐EpiCAREBrnoCzech Republic
- Central European Institute of Technology (CEITEC)Masaryk UniversityBrnoCzech Republic
| | - Martin Kojan
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of MedicineMasaryk University, Member of ERN‐EpiCAREBrnoCzech Republic
- Central European Institute of Technology (CEITEC)Masaryk UniversityBrnoCzech Republic
| | - Zdeněk Řehák
- Department of Nuclear MedicineMasaryk Memorial Cancer InstituteBrnoCzech Republic
| | - Milan Brázdil
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of MedicineMasaryk University, Member of ERN‐EpiCAREBrnoCzech Republic
- Central European Institute of Technology (CEITEC)Masaryk UniversityBrnoCzech Republic
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Khokhar SK, Kumar M, Kumar S, Manae T, Thanissery N, Ramakrishnan S, Arshad F, Nagaraj C, Mangalore S, Alladi S, Gandhi TK, Bharath RD. Alzheimer's Disease Is Associated with Increased Network Assortativity: Evidence from Metabolic Connectivity. Brain Connect 2023; 13:610-620. [PMID: 37930734 DOI: 10.1089/brain.2023.0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023] Open
Abstract
Introduction: Unraveling the network pathobiology in neurodegenerative disorders is a popular and promising field in research. We use a relatively newer network measure of assortativity in metabolic connectivity to understand network differences in patients with Alzheimer's Disease (AD), compared with those with mild cognitive impairment (MCI). Methods: Eighty-three demographically matched patients with dementia (56 AD and 27 MCI) who underwent positron emission tomography-magnetic resonance imaging (PET-MRI) study were recruited for this exploratory study. Global and nodal network measures obtained using the BRain Analysis using graPH theory toolbox were used to derive group-level differences (corrected p < 0.05). The methods were validated in age, and gender-matched 23 cognitively normal, 25 MCI, and 53 AD patients from the publicly available Alzheimer's Disease Neuroimaging Initiative (ADNI) data. Regions that revealed significant differences were correlated with the Addenbrooke's Cognitive Examination-III (ACE-III) scores. Results: Patients with AD revealed significantly increased global assortativity compared with the MCI group. In addition, they also revealed increased modularity and decreased participation coefficient. These findings were validated in the ADNI data. We also found that the regional standard uptake values of the right superior parietal and left superior temporal lobes were proportional to the ACE-III memory subdomain scores. Conclusion: Global errors associated with network assortativity are found in patients with AD, making the networks more regular and less resilient. Since the regional measures of these network errors were proportional to memory deficits, these measures could be useful in understanding the network pathobiology in AD.
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Affiliation(s)
- Sunil Kumar Khokhar
- Department of Neuroimaging and Interventional Radiology, and National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Manoj Kumar
- Department of Neuroimaging and Interventional Radiology, and National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Sandeep Kumar
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Tejaswini Manae
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Nithin Thanissery
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Subasree Ramakrishnan
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Faheem Arshad
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology, and National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Sandhya Mangalore
- Department of Neuroimaging and Interventional Radiology, and National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Suvarna Alladi
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Tapan K Gandhi
- Department of Electrical Engineering, Indian Institute of Technology (IIT) Delhi, New Delhi, Delhi, India
| | - Rose Dawn Bharath
- Department of Neuroimaging and Interventional Radiology, and National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
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Sala A, Herfert K, Gonzalez-Escamilla G, Caminiti SP, Bertoglio D. Editorial: Imaging brain molecular connectivity in health and disease. Front Hum Neurosci 2023; 17:1298382. [PMID: 37886691 PMCID: PMC10598374 DOI: 10.3389/fnhum.2023.1298382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023] Open
Affiliation(s)
- Arianna Sala
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Centre du Cerveau, University Hospital of Liège, Liège, Belgium
| | - Kristina Herfert
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Gabriel Gonzalez-Escamilla
- Movement Disorders and Neurostimulation, Department of Neurology, University Medical Hospital of the Johannes Gutenberg University Mainz, Mainz, Germany
| | | | - Daniele Bertoglio
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
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Devrome M, Van Laere K, Koole M. Multiplex core of the human brain using structural, functional and metabolic connectivity derived from hybrid PET-MR imaging. Front Neuroimaging 2023; 2:1115965. [PMID: 37645694 PMCID: PMC10461102 DOI: 10.3389/fnimg.2023.1115965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 07/06/2023] [Indexed: 08/31/2023]
Abstract
With the increasing success of mapping brain networks and availability of multiple MR- and PET-based connectivity measures, the need for novel methodologies to unravel the structure and function of the brain at multiple spatial and temporal scales is emerging. Therefore, in this work, we used hybrid PET-MR data of healthy volunteers (n = 67) to identify multiplex core nodes in the human brain. First, monoplex networks of structural, functional and metabolic connectivity were constructed, and consequently combined into a multiplex SC-FC-MC network by linking the same nodes categorically across layers. Taking into account the multiplex nature using a tensorial approach, we identified a set of core nodes in this multiplex network based on a combination of eigentensor centrality and overlapping degree. We introduced a coreness coefficient, which mitigates the effect of modeling parameters to obtain robust results. The proposed methodology was applied onto young and elderly healthy volunteers, where differences observed in the monoplex networks persisted in the multiplex as well. The multiplex core showed a decreased contribution to the default mode and salience network, while an increased contribution to the dorsal attention and somatosensory network was observed in the elderly population. Moreover, a clear distinction in eigentensor centrality was found between young and elderly healthy volunteers.
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Affiliation(s)
- Martijn Devrome
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
- Division of Nuclear Medicine, Universitair Ziekenhuis (UZ) Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
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Chaib S, Bouillot C, Bouvard S, Vidal B, Zimmer L, Levigoureux E. Single subanesthetic dose of ketamine produces delayed impact on brain [ 18F]FDG PET imaging and metabolic connectivity in rats. Front Neurosci 2023; 17:1213941. [PMID: 37521685 PMCID: PMC10372660 DOI: 10.3389/fnins.2023.1213941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/23/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction Ketamine, a glutamate NMDA receptor antagonist, is suggested to act very rapidly and durably on the depressive symptoms including treatment-resistant patients but its mechanisms of action remain unclear. There is a requirement for non-invasive biomarkers, such as imaging techniques, which hold promise in monitoring and elucidating its therapeutic impact. Methods We explored the glucose metabolism with [18F]FDG positron emission tomography (PET) in ten male rats in a longitudinal study designed to compare imaging patterns immediately after acute subanaesthetic ketamine injection (i.p. 10 mg/kg) with its sustained effects, 5 days later. Changes in [18F]FDG uptake following ketamine administration were estimated using a voxel-based analysis with SPM12 software, and a region of interest (ROI) analysis. A metabolic connectivity analysis was also conducted to estimate the immediate and delayed effects of ketamine on the inter-individual metabolic covariance between the ROIs. Results No significant difference was observed in brain glucose metabolism immediately following acute subanaesthetic ketamine injection. However, a significant decrease of glucose uptake appeared 5 days later, reflecting a sustained and delayed effect of ketamine in the frontal and the cingulate cortex. An increase in the raphe, caudate and cerebellum was also measured. Moreover, metabolic connectivity analyses revealed a significant decrease between the hippocampus and the thalamus at day 5 compared to the baseline. Discussion This study showed that the differences in metabolic profiles appeared belatedly, 5 days after ketamine administration, particularly in the cortical regions. Finally, this methodology will help to characterize the effects of future molecules for the treatment of treatment resistant depression.
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Affiliation(s)
- Sarah Chaib
- Université Claude Bernard Lyon 1, Lyon Neuroscience Research Center, CNRS, INSERM, Lyon, France
- Hospices Civils de Lyon, Lyon, France
| | | | - Sandrine Bouvard
- Université Claude Bernard Lyon 1, Lyon Neuroscience Research Center, CNRS, INSERM, Lyon, France
| | - Benjamin Vidal
- Université Claude Bernard Lyon 1, Lyon Neuroscience Research Center, CNRS, INSERM, Lyon, France
| | - Luc Zimmer
- Université Claude Bernard Lyon 1, Lyon Neuroscience Research Center, CNRS, INSERM, Lyon, France
- Hospices Civils de Lyon, Lyon, France
- CERMEP-Imaging Platform, Bron, France
| | - Elise Levigoureux
- Université Claude Bernard Lyon 1, Lyon Neuroscience Research Center, CNRS, INSERM, Lyon, France
- Hospices Civils de Lyon, Lyon, France
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Lin H, Pan T, Wang M, Ge J, Lu J, Ju Z, Chen K, Zhang H, Guan Y, Zhao Q, Shan B, Nie B, Zuo C, Wu P. Metabolic Asymmetry Relates to Clinical Characteristics and Brain Network Abnormalities in Alzheimer's Disease. J Alzheimers Dis 2023:JAD221258. [PMID: 37182878 DOI: 10.3233/jad-221258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
BACKGROUND Metabolic asymmetry has been observed in Alzheimer's disease (AD), but different studies have inconsistent viewpoints. OBJECTIVE To analyze the asymmetry of cerebral glucose metabolism in AD and investigate its clinical significance and potential metabolic network abnormalities. METHODS Standardized uptake value ratios (SUVRs) were obtained from 18F-FDG positron emission tomography (PET) images of all participants, and the asymmetry indices (AIs) were calculated according to the SUVRs. AD group was divided into left/right-dominant or bilateral symmetric hypometabolism (AD-L/AD-R or AD-BI) when more than half of the AIs of the 20 regions of interest (ROIs) were < -2SD, >2SD, or between±1SD. Differences in clinical features among the three AD groups were compared, and the abnormal network characteristics underlying metabolic asymmetry were explored. RESULTS In AD group, the proportions of AD-L, AD-R, and AD-BI were 28.4%, 17.9%, and 18.5%, respectively. AD-L/AD-R groups had younger age of onset and faster rate of cognitive decline than AD-BI group (p < 0.05). The absolute values of AIs in half of the 20 ROIs became higher at follow-up than at baseline (p < 0.05). Compared with those in AD-BI group, metabolic connection strength of network, global efficiency, cluster coefficient, degree centrality and local efficiency were lower, but shortest path length was longer in AD-L and AD-R groups (p < 0.05). CONCLUSION Asymmetric and symmetric hypometabolism may represent different clinical subtypes of AD, which may provide a clue for future studies on the heterogeneity of AD and help to optimize the design of clinical trials.
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Affiliation(s)
- Huamei Lin
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Tingting Pan
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High EnergyPhysics, Chinese Academy of Sciences, Beijing, China
| | - Min Wang
- Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai, China
| | - Jingjie Ge
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jiaying Lu
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Zizhao Ju
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Keliang Chen
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Huiwei Zhang
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yihui Guan
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Qianhua Zhao
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Baoci Shan
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High EnergyPhysics, Chinese Academy of Sciences, Beijing, China
| | - Binbin Nie
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High EnergyPhysics, Chinese Academy of Sciences, Beijing, China
| | - Chuantao Zuo
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Ping Wu
- Deparment of Nuclear Medicine / PET Center, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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Wang X, Lin D, Zhao C, Li H, Fu L, Huang Z, Xu S. Abnormal metabolic connectivity in default mode network of right temporal lobe epilepsy. Front Neurosci 2023; 17:1011283. [PMID: 37034164 PMCID: PMC10076532 DOI: 10.3389/fnins.2023.1011283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 03/06/2023] [Indexed: 04/11/2023] Open
Abstract
Aims Temporal lobe epilepsy (TLE) is a common neurological disorder associated with the dysfunction of the default mode network (DMN). Metabolic connectivity measured by 18F-fluorodeoxyglucose Positron Emission Computed Tomography (18F-FDG PET) has been widely used to assess cumulative energy consumption and provide valuable insights into the pathophysiology of TLE. However, the metabolic connectivity mechanism of DMN in TLE is far from fully elucidated. The present study investigated the metabolic connectivity mechanism of DMN in TLE using 18F-FDG PET. Method Participants included 40 TLE patients and 41 health controls (HC) who were age- and gender-matched. A weighted undirected metabolic network of each group was constructed based on 14 primary volumes of interest (VOIs) in the DMN, in which Pearson's correlation coefficients between each pair-wise of the VOIs were calculated in an inter-subject manner. Graph theoretic analysis was then performed to analyze both global (global efficiency and the characteristic path length) and regional (nodal efficiency and degree centrality) network properties. Results Metabolic connectivity in DMN showed that regionally networks changed in the TLE group, including bilateral posterior cingulate gyrus, right inferior parietal gyrus, right angular gyrus, and left precuneus. Besides, significantly decreased (P < 0.05, FDR corrected) metabolic connections of DMN in the TLE group were revealed, containing bilateral hippocampus, bilateral posterior cingulate gyrus, bilateral angular gyrus, right medial of superior frontal gyrus, and left inferior parietal gyrus. Conclusion Taken together, the present study demonstrated the abnormal metabolic connectivity in DMN of TLE, which might provide further insights into the understanding the dysfunction mechanism and promote the treatment for TLE patients.
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Affiliation(s)
- Xiaoyang Wang
- Department of Medical Imaging, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
- Department of Medical Imaging, Affiliated Dongfang Hospital, Xiamen University, Fuzhou, Fujian, China
| | - Dandan Lin
- Department of Clinical Medicine, Fujian Health College, Fuzhou, Fujian, China
| | - Chunlei Zhao
- Department of Medical Imaging, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
- Department of Medical Imaging, Affiliated Dongfang Hospital, Xiamen University, Fuzhou, Fujian, China
| | - Hui Li
- Department of Medical Imaging, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
| | - Liyuan Fu
- Department of Medical Imaging, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
- Department of Medical Imaging, Affiliated Dongfang Hospital, Xiamen University, Fuzhou, Fujian, China
| | - Zhifeng Huang
- Department of Medical Imaging, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
- Department of Medical Imaging, Affiliated Dongfang Hospital, Xiamen University, Fuzhou, Fujian, China
| | - Shangwen Xu
- Department of Medical Imaging, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
- Department of Medical Imaging, Affiliated Dongfang Hospital, Xiamen University, Fuzhou, Fujian, China
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Vo A, Schindlbeck KA, Nguyen N, Rommal A, Spetsieris PG, Tang CC, Choi YY, Niethammer M, Dhawan V, Eidelberg D. Adaptive and pathological connectivity responses in Parkinson's disease brain networks. Cereb Cortex 2023; 33:917-932. [PMID: 35325051 PMCID: PMC9930629 DOI: 10.1093/cercor/bhac110] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 11/12/2022] Open
Abstract
Functional imaging has been used extensively to identify and validate disease-specific networks as biomarkers in neurodegenerative disorders. It is not known, however, whether the connectivity patterns in these networks differ with disease progression compared to the beneficial adaptations that may also occur over time. To distinguish the 2 responses, we focused on assortativity, the tendency for network connections to link nodes with similar properties. High assortativity is associated with unstable, inefficient flow through the network. Low assortativity, by contrast, involves more diverse connections that are also more robust and efficient. We found that in Parkinson's disease (PD), network assortativity increased over time. Assoratitivty was high in clinically aggressive genetic variants but was low for genes associated with slow progression. Dopaminergic treatment increased assortativity despite improving motor symptoms, but subthalamic gene therapy, which remodels PD networks, reduced this measure compared to sham surgery. Stereotyped changes in connectivity patterns underlie disease progression and treatment responses in PD networks.
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Affiliation(s)
| | | | - Nha Nguyen
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Andrea Rommal
- Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
| | - Phoebe G Spetsieris
- Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
| | - Chris C Tang
- Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
| | - Yoon Young Choi
- Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
| | - Martin Niethammer
- Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
| | - Vijay Dhawan
- Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
| | - David Eidelberg
- Corresponding author: Center for Neurosciences, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.
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Voigt K, Liang EX, Misic B, Ward PGD, Egan GF, Jamadar SD. Metabolic and functional connectivity provide unique and complementary insights into cognition-connectome relationships. Cereb Cortex 2022; 33:1476-1488. [PMID: 35441214 PMCID: PMC9930619 DOI: 10.1093/cercor/bhac150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 11/13/2022] Open
Abstract
A major challenge in current cognitive neuroscience is how functional brain connectivity gives rise to human cognition. Functional magnetic resonance imaging (fMRI) describes brain connectivity based on cerebral oxygenation dynamics (hemodynamic connectivity), whereas [18F]-fluorodeoxyglucose functional positron emission tomography (FDG-fPET) describes brain connectivity based on cerebral glucose uptake (metabolic connectivity), each providing a unique characterization of the human brain. How these 2 modalities differ in their contribution to cognition and behavior is unclear. We used simultaneous resting-state FDG-fPET/fMRI to investigate how hemodynamic connectivity and metabolic connectivity relate to cognitive function by applying partial least squares analyses. Results revealed that although for both modalities the frontoparietal anatomical subdivisions related the strongest to cognition, using hemodynamic measures this network expressed executive functioning, episodic memory, and depression, whereas for metabolic measures this network exclusively expressed executive functioning. These findings demonstrate the unique advantages that simultaneous FDG-PET/fMRI has to provide a comprehensive understanding of the neural mechanisms that underpin cognition and highlights the importance of multimodality imaging in cognitive neuroscience research.
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Affiliation(s)
- Katharina Voigt
- Corresponding author: Turner Institute for Brain and Mental Health, Monash Biomedical Imaging, 770 Blackburn Road, Clayton, VIC 3800, Australia.
| | - Emma X Liang
- Monash Biomedical Imaging, Monash University, 770 Blackburn Road, 3800 Clayton VIC, Australia
| | - Bratislav Misic
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, 3801 University Street Montréal, Quebec H3A 2B4, Canada
| | - Phillip G D Ward
- Monash Biomedical Imaging, Monash University, 770 Blackburn Road, 3800 Clayton VIC, Australia
| | - Gary F Egan
- School of Psychological Sciences Turner and Turner Institute for Brain and Mental Health, Monash University, 18 Innovation Walk, 3800 Clayton VIC, Australia,Monash Biomedical Imaging, Monash University, 770 Blackburn Road, 3800 Clayton VIC, Australia
| | - Sharna D Jamadar
- School of Psychological Sciences Turner and Turner Institute for Brain and Mental Health, Monash University, 18 Innovation Walk, 3800 Clayton VIC, Australia,Monash Biomedical Imaging, Monash University, 770 Blackburn Road, 3800 Clayton VIC, Australia
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Jamadar SD, Egan GF. Resting-State FDG-PET Connectivity: Covariance, Ergodicity, and Biomarkers. Response to Commentary by Sala et al.; Static versus Functional PET: Making Sense of Metabolic Connectivity. Cereb Cortex 2021; 32:2054-2055. [PMID: 34613341 DOI: 10.1093/cercor/bhab316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sharna D Jamadar
- Monash Biomedical Imaging, Monash University, Clayton, VIC 3800, Australia
| | - Gary F Egan
- Monash Biomedical Imaging, Monash University, Clayton, VIC 3800, Australia
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Zorzi G, Cecchin D, Bussè C, Perini G, Corbetta M, Cagnin A. Changes of Metabolic Connectivity in Dementia with Lewy Bodies with Visual Hallucinations: A 18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Study. Brain Connect 2021; 11:518-528. [PMID: 33757301 DOI: 10.1089/brain.2020.0988] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: Recurrent complex visual hallucinations (VHs) are common in dementia with Lewy bodies (DLB). Previous investigations suggest that VHs are associated with connectivity changes within and between large scale networks involved in visual processing and attention. Aim: To examine more directly whether VH in DLB reflects direct changes in neuronal activity between cortical regions assessing metabolic connectivity with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/magnetic resonance and graph theory. Methods: Twenty-six patients with probable DLB (13 VHs and 13 no-VHs; mean age: 72.9 ± 6.87 years vs. 70.2 ± 7.96 years) were enrolled. T1-weighted 3T-MR images and FDG-PET data were coacquired using an integrated PET/MR scanner. MR images defined cortical parcels of the Shaefer-Yeo atlas for multiple functional networks. We computed in each parcel the regional standardized-uptake-values (SUV) corrected for partial volume and normalized to the cerebellar cortex. Strength degree, clustering coefficient, characteristic path length, and hubs were analyzed with graph analysis. Results: The mean 18F-FDG-PET SUVr of parcels belonging to the visual and dorsal attention networks (DANs) were significantly lower in the VH group (p = 0.01). Metabolism in the right temporoparietal cortex correlated with VH severity (R = -0.58; p < 0.01). VH patients showed weaker metabolic connectivity in the parietal, temporal, and occipital cortex of the default mode network, DAN, and visual networks, but more robust connectivity in the right insula and orbitofrontal cortex. A lower global efficiency characterized the VH group, except for ventral attention network and limbic network. Conclusions: VHs in DLB correlate with lower glucose metabolism and weaker metabolic connectivity in the parietal-occipital cortex, but stronger connectivity in the limbic system. Impact statement This study shows that application of the graph theory to 18F-fluorodeoxyglucose-positron emission tomography data, commonly acquired during the diagnostic workflow in neurodegenerative diseases, could be used to obtain information of functional connectivity at a group level, with results that are consistent with other data commonly used in brain functional investigation (e.g., electroencephalography or functional magnetic resonance). New network-based methods of metabolic image analyses, such as graph analysis, are a recent area of research with a potential capacity to extract information on alterations of metabolic connectivity that may become pharmacological and neuromodulation targets of the physiopathology of recurrent complex visual hallucinations.
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Affiliation(s)
- Giovanni Zorzi
- Department of Neuroscience, University of Padova, Padova, Italy.,Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Diego Cecchin
- Padova Neuroscience Center, University of Padova, Padova, Italy.,Nuclear Medicine Unit, Department of Medicine, University of Padova, Padova, Italy
| | - Cinzia Bussè
- Department of Neuroscience, University of Padova, Padova, Italy
| | | | - Maurizio Corbetta
- Department of Neuroscience, University of Padova, Padova, Italy.,Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Annachiara Cagnin
- Department of Neuroscience, University of Padova, Padova, Italy.,Padova Neuroscience Center, University of Padova, Padova, Italy
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12
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Jamadar SD, Ward PGD, Liang EX, Orchard ER, Chen Z, Egan GF. Metabolic and Hemodynamic Resting-State Connectivity of the Human Brain: A High-Temporal Resolution Simultaneous BOLD-fMRI and FDG-fPET Multimodality Study. Cereb Cortex 2021; 31:2855-2867. [PMID: 33529320 DOI: 10.1093/cercor/bhaa393] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/26/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022] Open
Abstract
Simultaneous [18F]-fluorodeoxyglucose positron emission tomography functional magnetic resonance imaging (FDG-PET/fMRI) provides the capacity to image 2 sources of energetic dynamics in the brain-glucose metabolism and the hemodynamic response. fMRI connectivity has been enormously useful for characterizing interactions between distributed brain networks in humans. Metabolic connectivity based on static FDG-PET has been proposed as a biomarker for neurological disease, but FDG-sPET cannot be used to estimate subject-level measures of "connectivity," only across-subject "covariance." Here, we applied high-temporal resolution constant infusion functional positron emission tomography (fPET) to measure subject-level metabolic connectivity simultaneously with fMRI connectivity. fPET metabolic connectivity was characterized by frontoparietal connectivity within and between hemispheres. fPET metabolic connectivity showed moderate similarity with fMRI primarily in superior cortex and frontoparietal regions. Significantly, fPET metabolic connectivity showed little similarity with FDG-sPET metabolic covariance, indicating that metabolic brain connectivity is a nonergodic process whereby individual brain connectivity cannot be inferred from group-level metabolic covariance. Our results highlight the complementary strengths of fPET and fMRI in measuring the intrinsic connectivity of the brain and open up the opportunity for novel fundamental studies of human brain connectivity as well as multimodality biomarkers of neurological diseases.
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Affiliation(s)
- Sharna D Jamadar
- Monash Biomedical Imaging, Melbourne, Vic, 3800 Australia.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, Vic, 3800 Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne 3800, Australia
| | - Phillip G D Ward
- Monash Biomedical Imaging, Melbourne, Vic, 3800 Australia.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, Vic, 3800 Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne 3800, Australia
| | - Emma X Liang
- Monash Biomedical Imaging, Melbourne, Vic, 3800 Australia
| | - Edwina R Orchard
- Monash Biomedical Imaging, Melbourne, Vic, 3800 Australia.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, Vic, 3800 Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne 3800, Australia
| | - Zhaolin Chen
- Monash Biomedical Imaging, Melbourne, Vic, 3800 Australia.,Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, Vic, 3800 Australia
| | - Gary F Egan
- Monash Biomedical Imaging, Melbourne, Vic, 3800 Australia.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, Vic, 3800 Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne 3800, Australia
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13
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Grosch M, Beyer L, Lindner M, Kaiser L, Ahmadi SA, Stockbauer A, Bartenstein P, Dieterich M, Brendel M, Zwergal A, Ziegler S. Metabolic connectivity-based single subject classification by multi-regional linear approximation in the rat. Neuroimage 2021; 235:118007. [PMID: 33831550 DOI: 10.1016/j.neuroimage.2021.118007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 10/21/2022] Open
Abstract
Metabolic connectivity patterns on the basis of [18F]-FDG positron emission tomography (PET) are used to depict complex cerebral network alterations in different neurological disorders and therefore may have the potential to support diagnostic decisions. In this study, we established a novel statistical classification method taking advantage of differential time-dependent states of whole-brain metabolic connectivity following unilateral labyrinthectomy (UL) in the rat and explored its classification accuracy. The dataset consisted of repeated [18F]-FDG PET measurements at baseline and 1, 3, 7, and 15 days (= maximum of 5 classes) after UL with 17 rats per measurement day. Classification in different stages after UL was performed by determining connectivity patterns for the different classes by Pearson's correlation between uptake values in atlas-based segmented brain regions. Connections were fitted with a linear function, with which different thresholds on the correlation coefficient (r = [0.5, 0.85]) were investigated. Rats were classified by determining the congruence of their PET uptake pattern with the fitted connectivity patterns in the classes. Overall, the classification accuracy with this method was 84.3% for 3 classes, 75.0% for 4 classes, and 54.1% for 5 classes and outperformed random classification as well as machine learning classification on the same dataset. The optimal classification thresholds of the correlation coefficient and distance-to-fit were found to be |r| > 0.65 and d = 4 when using Siegel's slope estimator for fitting. This connectivity-based classification method can compete with machine learning classification and may have methodological advantages when applied to support PET-based diagnostic decisions in neurological network disorders (such as neurodegenerative syndromes).
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Affiliation(s)
- Maximilian Grosch
- German Center for Vertigo and Balance Disorders, DSGZ, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistrasse 15, D-81377 Munich, Germany; Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany.
| | - Leonie Beyer
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany
| | - Magdalena Lindner
- German Center for Vertigo and Balance Disorders, DSGZ, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistrasse 15, D-81377 Munich, Germany; Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany
| | - Lena Kaiser
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany
| | - Seyed-Ahmad Ahmadi
- German Center for Vertigo and Balance Disorders, DSGZ, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistrasse 15, D-81377 Munich, Germany
| | - Anna Stockbauer
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany; Munich Cluster of Systems Neurology, SyNergy, Munich, Germany
| | - Marianne Dieterich
- German Center for Vertigo and Balance Disorders, DSGZ, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistrasse 15, D-81377 Munich, Germany; Department of Neurology, University Hospital, LMU Munich, Munich, Germany; Munich Cluster of Systems Neurology, SyNergy, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany; Munich Cluster of Systems Neurology, SyNergy, Munich, Germany
| | - Andreas Zwergal
- German Center for Vertigo and Balance Disorders, DSGZ, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistrasse 15, D-81377 Munich, Germany; Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - Sibylle Ziegler
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich Germany
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14
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Boccalini C, Carli G, Pilotto A, Padovani A, Perani D. Gender-Related Vulnerability of Dopaminergic Neural Networks in Parkinson's Disease. Brain Connect 2020; 11:3-11. [PMID: 33198485 DOI: 10.1089/brain.2020.0781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Background: In Parkinson's disease (PD), neurodegeneration of dopaminergic systems leads to motor and non-motor abnormalities. Sex might influence the clinical PD phenotypes and progression. Previous molecular imaging data focused only on the nigro-striato-cortical dopamine system that appeared more preserved in women. There is still a lack of evidence on gender/sex differences in the mesolimbic dopaminergic system. We aimed at assessing PD gender differences in both the dopaminergic pathways, by using a brain metabolic connectivity approach. This is based on the evidence of a significant coupling between the neurotransmission and metabolic impairments. Methods: We included 34 idiopathic PD patients (Female/Male: 16/18) and 34 healthy controls for comparison. The molecular architecture of both the dopaminergic networks was estimated throughout partial correlation analyses using brain metabolism data obtained by fluorine-18-fluorodeoxyglucose positron emission tomography (threshold set at p < 0.01, corrected for Bonferroni multiple comparisons). Results: Male patients were characterized by a widespread altered connectivity in the nigro-striato-cortical network and a sparing of the mesolimbic pathway. On the contrary, PD females showed a severe altered connectivity in the mesolimbic network and only a partial reconfiguration of the nigro-striato-cortical network. Discussion: Our findings add remarkable knowledge on the neurobiology of gender differences in PD, with the identification of specific neural vulnerabilities. The gender differences here revealed might be due to the combination of both biological and sociodemographic life factors. Gender differences in PD should be considered also for treatments and the targeting of modifiable risk factors.
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Affiliation(s)
- Cecilia Boccalini
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Giulia Carli
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Andrea Pilotto
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.,Parkinson's Disease Rehabilitation Centre, FERB ONLUS S. Isidoro Hospital, Trescore, Italy
| | - Alessandro Padovani
- Parkinson's Disease Rehabilitation Centre, FERB ONLUS S. Isidoro Hospital, Trescore, Italy
| | - Daniela Perani
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.,Nuclear Medicine Unit, San Raffaele Hospital, Milan, Italy
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15
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Hou AL, Zheng MX, Hua XY, Huo BB, Shen J, Xu JG. Electroacupuncture-Related Metabolic Brain Connectivity in Neuropathic Pain due to Brachial Plexus Avulsion Injury in Rats. Front Neural Circuits 2020; 14:35. [PMID: 32625066 PMCID: PMC7313422 DOI: 10.3389/fncir.2020.00035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022] Open
Abstract
Objective: The present study aimed to investigate the analgesic effect of electroacupuncture (EA) in neuropathic pain due to brachial plexus avulsion injury (BPAI) and related changes in the metabolic brain connectivity. Methods: Neuropathic pain model due to BPAI was established in adult female Sprague-Dawley rats. EA stimulations (2/15 Hz, 30 min/day, 5-day intervention followed by 2-day rest in each session) were applied to the fifth-seventh cervical "Jiaji" acupoints on the noninjured side from 1st to 12th weeks following BPAI (EA group, n = 8). Three control groups included sham EA (nonelectrical acupuncture applied to 3 mm lateral to the real "Jiaji" acupoints), BPAI-only, and normal rats (no particular intervention; eight rats in each group). Thermal withdrawal latency (TWL) of the noninjured forepaw was regularly tested to evaluate the threshold of thermalgesia. Small animal [fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) PET/CT scans of brain were conducted at the end of 4th, 12th, and 16th weeks to explore metabolic alterations of brain. Results: In the EA group, the TWL of the noninjured forepaw significantly decreased following BPAI and then increased following EA stimulation, compared with sham EA (P < 0.001). The metabolic brain connectivity among somatosensory cortex (SC), motor cortex (MC), caudate putamen (Cpu), and dorsolateral thalamus (DLT) in bilateral hemispheres decreased throughout the 16 weeks' observation in the BPAI-only group, compared with the normal rats (P < 0.05). In the EA group, the strength of connectivity among the above regions were found to be increased at the end of 4th week following BPAI modeling, decreased at 12th week, and then increased again at 16th week (P < 0.05). The changes in metabolic connectivity were uncharacteristic and dispersed in the sham EA group. Conclusion: The study revealed long-term and extensive changes of metabolic brain connectivity in EA-treated BPAI-induced neuropathic pain rats. Bilateral sensorimotor and pain-related brain regions were mainly involved in this process. It indicated that modulation of brain metabolic connectivity might be an important mechanism of analgesic effect in EA stimulation for the treatment of neuropathic pain.
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Affiliation(s)
- Ao-Lin Hou
- Shanghai Eighth People Hospital, Shanghai, China
| | - Mou-Xiong Zheng
- Department of Traumatology and Orthopedics, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xu-Yun Hua
- Department of Traumatology and Orthopedics, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Bei-Bei Huo
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jun Shen
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Department of Orthopedics, Guanghua Hospital of Integrative Chinese and Western Medicine, Shanghai, China
| | - Jian-Guang Xu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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16
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Di X, Wölfer M, Amend M, Wehrl H, Ionescu TM, Pichler BJ, Biswal BB. Interregional causal influences of brain metabolic activity reveal the spread of aging effects during normal aging. Hum Brain Mapp 2019; 40:4657-4668. [PMID: 31389641 DOI: 10.1002/hbm.24728] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 11/08/2022] Open
Abstract
During healthy brain aging, different brain regions show anatomical or functional declines at different rates, and some regions may show compensatory increases in functional activity. However, few studies have explored interregional influences of brain activity during the aging process. We proposed a causality analysis framework combining high dimensionality independent component analysis (ICA), Granger causality, and least absolute shrinkage and selection operator regression on longitudinal brain metabolic activity data measured by Fludeoxyglucose positron emission tomography (FDG-PET). We analyzed FDG-PET images from healthy old subjects, who were scanned for at least five sessions with an averaged intersession interval of 1 year. The longitudinal data were concatenated across subjects to form a time series, and the first-order autoregressive model was used to measure interregional causality among the independent sources of metabolic activity identified using ICA. Several independent sources with reduced metabolic activity in aging, including the anterior temporal lobe and orbital frontal cortex, demonstrated causal influences over many widespread brain regions. On the other hand, the influenced regions were more distributed, and had smaller age-related declines or even relatively increased metabolic activity. The current data demonstrated interregional spreads of aging on metabolic activity at the scale of a year, and have identified key brain regions in the aging process that have strong influences over other regions.
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Affiliation(s)
- Xin Di
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey.,School of Life Sciences and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Marie Wölfer
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey.,Clinical Affective Neuroimaging Laboratory (CANLAB), Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Department for Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Mario Amend
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Hans Wehrl
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Tudor M Ionescu
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Bernd J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Bharat B Biswal
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey.,School of Life Sciences and Technology, University of Electronic Science and Technology of China, Chengdu, China
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17
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Huo BB, Shen J, Hua XY, Zheng MX, Lu YC, Wu JJ, Shan CL, Xu JG. Alteration of metabolic connectivity in a rat model of deafferentation pain: a 18F-FDG PET/CT study. J Neurosurg 2019; 132:1295-1303. [PMID: 30835695 DOI: 10.3171/2018.11.jns181815] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/21/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Refractory deafferentation pain has been evidenced to be related to central nervous system neuroplasticity. In this study, the authors sought to explore the underlying glucose metabolic changes in the brain after brachial plexus avulsion, particularly metabolic connectivity. METHODS Rats with unilateral deafferentation following brachial plexus avulsion, a pain model of deafferentation pain, were scanned by small-animal 2-deoxy-[18F]fluoro-d-glucose (18F-FDG) PET/CT to explore the changes of metabolic connectivity among different brain regions. Thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) of the intact forepaw were also measured for evaluating pain sensitization. Brain metabolic connectivity and TWL were compared from baseline to 1 week after brachial plexus avulsion. RESULTS Alterations of metabolic connectivity occurred not only within the unilateral hemisphere contralateral to the injured forelimb, but also in the other hemisphere and even in the connections between bilateral hemispheres. Metabolic connectivity significantly decreased between sensorimotor-related areas within the left hemisphere (contralateral to the injured forelimb) (p < 0.05), as well as between areas across bilateral hemispheres (p < 0.05). Connectivity between areas within the right hemisphere (ipsilateral to the injured forelimb) significantly increased (p = 0.034). TWL and MWT of the left (intact) forepaw after surgery were significantly lower than those at baseline (p < 0.001). CONCLUSIONS This study revealed that unilateral brachial plexus avulsion facilitates pain sensitization in the opposite limb. A specific pattern of brain metabolic changes occurred in this procedure. Metabolic connectivity reorganized not only in the sensorimotor area corresponding to the affected forelimb, but also in extensive areas involving the bilateral hemispheres. These findings may broaden our understanding of central nervous system changes, as well as provide new information and a potential intervention target for nosogenesis of deafferentation pain.
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Affiliation(s)
- Bei-Bei Huo
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and
| | - Jun Shen
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and
| | - Xu-Yun Hua
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and.,3Trauma and Orthopedics, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Mou-Xiong Zheng
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and.,3Trauma and Orthopedics, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ye-Chen Lu
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and
| | - Jia-Jia Wu
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and.,Departments of2Rehabilitation Medicine and
| | - Chun-Lei Shan
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and.,Departments of2Rehabilitation Medicine and
| | - Jian-Guang Xu
- 1School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine; and.,Departments of2Rehabilitation Medicine and
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18
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Yu R, Park HJ, Cho H, Ko A, Pae C, Oh MK, Kang HC, Kim HD, Park EK, Shim KW, Kim DS, Lee JS. Interregional metabolic connectivity of 2-deoxy-2[ 18 F]fluoro-D-glucose positron emission tomography in vagus nerve stimulation for pediatric patients with epilepsy: A retrospective cross-sectional study. Epilepsia 2018; 59:2249-2259. [PMID: 30370541 DOI: 10.1111/epi.14590] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/02/2018] [Accepted: 10/02/2018] [Indexed: 12/31/2022]
Abstract
OBJECTIVE With the recognition of epilepsy as a network disease that disrupts the organizing ability of resting-state brain networks, vagus nerve stimulation (VNS) may control epileptic seizures through modulation of functional connectivity. We evaluated preoperative 2-deoxy-2[18 F]fluoro-D-glucose (FDG) positron emission tomography (PET) in VNS-implanted pediatric patients with refractory epilepsy to analyze the metabolic connectivity of patients and its prognostic role in seizure control. METHODS Preoperative PET data of 66 VNS pediatric patients who were followed up for a minimum of 1 year after the procedure were collected for the study. Retrospective review of the patients' charts was performed, and five patients with inappropriate PET data or major health issues were excluded. We conducted an independent component analysis of FDG-PET to extract spatial metabolic components and their activities, which were used to perform cross-sectional metabolic network analysis. We divided the patients into VNS-effective and VNS-ineffective groups (VNS-effective group, ≥50% seizure reduction; VNS-ineffective group, <50% reduction) and compared metabolic connectivity differences between groups using a permutation test. RESULTS Thirty-four (55.7%) patients showed >50% seizure reduction from baseline frequency 1 year after VNS. A significant difference in metabolic connectivity evaluated by preoperative FDG-PET was noted between groups. Relative changes in glucose metabolism were strongly connected among the areas of brainstem, cingulate gyrus, cerebellum, bilateral insula, and putamen in patients with <50% seizure control after VNS. SIGNIFICANCE This study shows that seizure outcome of VNS may be influenced by metabolic connectivity, which can be obtained from preoperative PET imaging. This study of metabolic connectivity analysis may contribute in further understanding of the mechanism of VNS in intractable seizures.
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Affiliation(s)
- Rita Yu
- Department of Pediatrics, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
| | - Hae-Jeong Park
- Departments of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea.,BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Hojin Cho
- Departments of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Ara Ko
- Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University College of Medicine, Yangsan, Korea
| | - Chongwon Pae
- Departments of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea.,BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Maeng-Keun Oh
- Departments of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Heung Dong Kim
- Division of Pediatric Neurology, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Eun-Kyung Park
- Department of Pediatric Neurosurgery, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Kyu-Won Shim
- Department of Pediatric Neurosurgery, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Dong Suk Kim
- Department of Pediatric Neurosurgery, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Joon Soo Lee
- Division of Pediatric Neurology, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
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19
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Verger A, Klesse E, Chawki MB, Witjas T, Azulay J, Eusebio A, Guedj E. Brain PET substrate of impulse control disorders in Parkinson's disease: A metabolic connectivity study. Hum Brain Mapp 2018; 39:3178-3186. [PMID: 29635851 PMCID: PMC6866256 DOI: 10.1002/hbm.24068] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 12/21/2022] Open
Abstract
Impulse control disorders (ICDs) have received increased attention in Parkinson's disease (PD) because of potentially dramatic consequences. Their physiopathology, however, remains incompletely understood. An overstimulation of the mesocorticolimbic system has been reported, while a larger network has recently been suggested. The aim of this study is to specifically describe the metabolic PET substrate and related connectivity changes in PD patients with ICDs. Eighteen PD patients with ICDs and 18 PD patients without ICDs were evaluated using cerebral 18F-fluorodeoxyglucose positron emission tomography. SPM-T maps comparisons were performed between groups and metabolic connectivity was evaluated by interregional correlation analysis (IRCA; p < .005, uncorrected; k > 130) and by graph theory (p < .05). PD patients with ICDs had relative increased metabolism in the right middle and inferior temporal gyri compared to those without ICDs. The connectivity of this area was increased mostly with the mesocorticolimbic system, positively with the orbitofrontal region, and negatively with both the right parahippocampus and the left caudate (IRCA). Moreover, the betweenness centrality of this area with the mesocorticolimbic system was lost in patients with ICDs (graph analysis). ICDs are associated in PD with the dysfunction of a network exceeding the mesocorticolimbic system, and especially the caudate, the parahippocampus, and the orbitofrontal cortex, remotely including the right middle and inferior temporal gyri. This latest area loses its central place with the mesocorticolimbic system through a connectivity dysregulation.
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Affiliation(s)
- Antoine Verger
- Department of Nuclear MedicineAssistance Publique‐Hôpitaux de Marseille, Aix‐Marseille Université, Timone University HospitalProvence‐Alpes‐Côte d'AzurFrance
- Department of Nuclear Medicine & Nancyclotep Imaging platformCHRU NancyNancyF‐54000France
- Université de Lorraine, INSERM, IADINancyF‐54000France
| | - Elsa Klesse
- Department of Neurology and Movement DisordersAssistance Publique‐Hôpitaux de Marseille, Aix‐Marseille Université, Timone University HospitalProvence‐Alpes‐Côte d'AzurFrance
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut FresnelMarseilleFrance
| | - Mohammad B. Chawki
- Department of Nuclear Medicine & Nancyclotep Imaging platformCHRU NancyNancyF‐54000France
| | - Tatiana Witjas
- Department of Neurology and Movement DisordersAssistance Publique‐Hôpitaux de Marseille, Aix‐Marseille Université, Timone University HospitalProvence‐Alpes‐Côte d'AzurFrance
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut FresnelMarseilleFrance
| | - Jean‐Philippe Azulay
- Department of Neurology and Movement DisordersAssistance Publique‐Hôpitaux de Marseille, Aix‐Marseille Université, Timone University HospitalProvence‐Alpes‐Côte d'AzurFrance
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut FresnelMarseilleFrance
| | - Alexandre Eusebio
- Department of Neurology and Movement DisordersAssistance Publique‐Hôpitaux de Marseille, Aix‐Marseille Université, Timone University HospitalProvence‐Alpes‐Côte d'AzurFrance
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut FresnelMarseilleFrance
| | - Eric Guedj
- Department of Nuclear MedicineAssistance Publique‐Hôpitaux de Marseille, Aix‐Marseille Université, Timone University HospitalProvence‐Alpes‐Côte d'AzurFrance
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut FresnelMarseilleFrance
- CERIMED, Aix‐Marseille UniversitéMarseilleFrance
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20
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Chang YT, Huang CW, Huang SH, Hsu SW, Chang WN, Lee JJ, Chang CC. Genetic interaction is associated with lower metabolic connectivity and memory impairment in clinically mild Alzheimer's disease. Genes Brain Behav 2018; 18:e12490. [PMID: 29883038 DOI: 10.1111/gbb.12490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/29/2018] [Accepted: 06/06/2018] [Indexed: 11/29/2022]
Abstract
Metabolic connectivity as showed by [18F] fluorodeoxyglucose (FDG) positron emission tomography (FDG-PET) reflects neuronal connectivity. The aim of this study was to investigate the genetic impact on metabolic connectivity in default mode subnetworks and its clinical-pathological relationships in patients with Alzheimer's disease (AD). We separately investigated the modulation of 2 default mode subnetworks, as identified with independent component analysis, by comparing APOE-ε4 carriers to noncarriers with AD. We further analyzed the interaction effects of APOE (APOE-ε4 carriers vs noncarriers) with PICALM (rs3851179-GG vs rs3851179-A-allele carriers) on episodic memory (EM) deficits, reduction in cerebral metabolic rate for glucose (CMRgl) and decreased metabolic connectivity in default mode subnetworks. The metabolic connectivity in the ventral default mode network (vDMN) was positively correlated with EM scores (β =0.441, P < .001). The APOE-ε4 carriers had significantly lower metabolic connectivity in the vDMN than the APOE-ε4 carriers (t(96) = -2.233, P = .028). There was an effect of the APOE-PICALM (rs3851179) interactions on reduced CMRgl in regions of vDMN (P < .001), and on memory deficits (F3,93 =5.568, P = .020). This study identified that PICALM may modulates memory deficits, reduced CMRgl and decreased metabolic connectivity in the vDMN in APOE-ε4 carriers. [18F] FDG-PET-based metabolic connectivity may serve a useful tool to elucidate the neural networks underlying clinical-pathological relationships in AD.
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Affiliation(s)
- Y-T Chang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - C-W Huang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - S-H Huang
- Department of Nuclear Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - S-W Hsu
- Department of Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - W-N Chang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - J-J Lee
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - C-C Chang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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21
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Kim JA, Jeong JW, Behen ME, Pilli VK, Luat A, Chugani HT, Juhász C. Metabolic correlates of cognitive function in children with unilateral Sturge-Weber syndrome: Evidence for regional functional reorganization and crowding. Hum Brain Mapp 2017; 39:1596-1606. [PMID: 29274110 DOI: 10.1002/hbm.23937] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/21/2017] [Accepted: 12/14/2017] [Indexed: 01/01/2023] Open
Abstract
To evaluate metabolic changes in the ipsi- and contralateral hemisphere in children showing a cognitive profile consistent with early reorganization of cognitive function, we evaluated the regional glucose uptake, interhemispheric metabolic connectivity, and cognitive function in children with unilateral SWS. Interictal 2-deoxy-2[18 F]fluoro-D-glucose (FDG)-PET scans of 27 children with unilateral SWS and mild epilepsy and 27 age-matched control (non-SWS children with epilepsy and normal FDG-PET) were compared using statistical parametric mapping (SPM). Regional FDG-PET abnormalities calculated as SPM(t) scores in the SWS group were correlated with cognitive function (IQ) in left- and right-hemispheric subgroups. Interhemispheric metabolic connectivity between homotopic cortical regions was also calculated. Verbal IQ was substantially (≥10 points difference) higher than non-verbal IQ in 61% of the right- and 71% of the left-hemispheric SWS group. FDG SPM(t) scores in the affected hemisphere showed strong positive correlations with IQ in the left-hemispheric, but not in right-hemispheric SWS group in several frontal, parietal, and temporal cortical regions. Significant positive interhemispheric metabolic connectivity, present in controls, was diminished in the SWS group. In addition, the left-hemispheric SWS group showed inverse metabolic interhemispheric correlations in specific parietal, temporal, and occipital regions. FDG SPM(t) scores in the same regions of the right (unaffected) hemisphere showed inverse correlations with IQ. These findings suggest that left-hemispheric lesions in SWS often result in early reorganization of verbal functions while interfering with ("crowding") their non-verbal cognitive abilities. These cognitive changes are associated with specific metabolic abnormalities in the contralateral hemisphere not directly affected by SWS.
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Affiliation(s)
- Jeong-A Kim
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan, USA.,The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Jeong-Won Jeong
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan, USA.,The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Michael E Behen
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan, USA.,The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Vinod K Pilli
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan, USA.,The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Aimee Luat
- The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Harry T Chugani
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan, USA.,The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Neurology, Nemours DuPont Hospital for Children, Wilmington, Delaware, USA.,Department of Neurology, School of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Csaba Juhász
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan, USA.,The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
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22
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Carbonell F, Zijdenbos AP, McLaren DG, Iturria-Medina Y, Bedell BJ. Modulation of glucose metabolism and metabolic connectivity by β-amyloid. J Cereb Blood Flow Metab 2016; 36:2058-2071. [PMID: 27301477 PMCID: PMC5363668 DOI: 10.1177/0271678x16654492] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/17/2016] [Indexed: 11/17/2022]
Abstract
Glucose hypometabolism in the pre-clinical stage of Alzheimer's disease (AD) has been primarily associated with the APOE ɛ4 genotype, rather than fibrillar β-amyloid. In contrast, aberrant patterns of metabolic connectivity are more strongly related to β-amyloid burden than APOE ɛ4 status. A major limitation of previous studies has been the dichotomous classification of subjects as amyloid-positive or amyloid-negative. Dichotomous treatment of a continuous variable, such as β-amyloid, potentially obscures the true relationship with metabolism and reduces the power to detect significant changes in connectivity. In the present work, we assessed alterations of glucose metabolism and metabolic connectivity as continuous function of β-amyloid burden using positron emission tomography scans from the Alzheimer's Disease Neuroimaging Initiative study. Modeling β-amyloid as a continuous variable resulted in better model fits and improved power compared to the dichotomous model. Using this continuous model, we found that both APOE ɛ4 genotype and β-amyloid burden are strongly associated with glucose hypometabolism at early stages of Alzheimer's disease. We also determined that the cumulative effects of β-amyloid deposition result in a particular pattern of altered metabolic connectivity, which is characterized by global, synchronized hypometabolism at early stages of the disease process, followed by regionally heterogeneous, progressive hypometabolism.
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Affiliation(s)
| | | | | | | | - Barry J Bedell
- Biospective Inc., Montreal, Canada.,McGill University, Montreal, Canada
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23
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Rohleder C, Wiedermann D, Neumaier B, Drzezga A, Timmermann L, Graf R, Leweke FM, Endepols H. The Functional Networks of Prepulse Inhibition: Neuronal Connectivity Analysis Based on FDG-PET in Awake and Unrestrained Rats. Front Behav Neurosci 2016; 10:148. [PMID: 27493627 PMCID: PMC4954847 DOI: 10.3389/fnbeh.2016.00148] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/06/2016] [Indexed: 12/21/2022] Open
Abstract
Prepulse inhibition (PPI) is a neuropsychological process during which a weak sensory stimulus (“prepulse”) attenuates the motor response (“startle reaction”) to a subsequent strong startling stimulus. It is measured as a surrogate marker of sensorimotor gating in patients suffering from neuropsychological diseases such as schizophrenia, as well as in corresponding animal models. A variety of studies has shown that PPI of the acoustical startle reaction comprises three brain circuitries for: (i) startle mediation, (ii) PPI mediation, and (iii) modulation of PPI mediation. While anatomical connections and information flow in the startle and PPI mediation pathways are well known, spatial and temporal interactions of the numerous regions involved in PPI modulation are incompletely understood. We therefore combined [18F]fluoro-2-deoxyglucose positron-emission-tomography (FDG-PET) with PPI and resting state control paradigms in awake rats. A battery of subtractive, correlative as well as seed-based functional connectivity analyses revealed a default mode-like network (DMN) active during resting state only. Furthermore, two functional networks were observed during PPI: Metabolic activity in the lateral circuitry was positively correlated with PPI effectiveness and involved the auditory system and emotional regions. The medial network was negatively correlated with PPI effectiveness, i.e., associated with startle, and recruited a spatial/cognitive network. Our study provides evidence for two distinct neuronal networks, whose continuous interplay determines PPI effectiveness in rats, probably by either protecting the prepulse or facilitating startle processing. Discovering similar networks affected in neuropsychological disorders may help to better understand mechanisms of sensorimotor gating deficits and provide new perspectives for therapeutic strategies.
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Affiliation(s)
- Cathrin Rohleder
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg UniversityMannheim, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of CologneCologne, Germany
| | - Dirk Wiedermann
- In-Vivo NMR Laboratory, Max-Planck-Institute for Metabolism Research Cologne, Germany
| | - Bernd Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of CologneCologne, Germany; Forschungszentrum Jülich GmbH, Institute of Neurosciences and Medicine, INM-5: Nuclear ChemistryJülich, Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, University Hospital of Cologne Cologne, Germany
| | - Lars Timmermann
- Department of Neurology, University Hospital of Cologne Cologne, Germany
| | - Rudolf Graf
- Multimodal Imaging of Brain Metabolism, Max-Planck-Institute for Metabolism Research Cologne, Germany
| | - F Markus Leweke
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University Mannheim, Germany
| | - Heike Endepols
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne Cologne, Germany
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24
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Ballarini T, Iaccarino L, Magnani G, Ayakta N, Miller BL, Jagust WJ, Gorno-Tempini ML, Rabinovici GD, Perani D. Neuropsychiatric subsyndromes and brain metabolic network dysfunctions in early onset Alzheimer's disease. Hum Brain Mapp 2016; 37:4234-4247. [PMID: 27412866 DOI: 10.1002/hbm.23305] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/14/2016] [Accepted: 06/23/2016] [Indexed: 12/23/2022] Open
Abstract
Neuropsychiatric symptoms (NPSs) often occur in early-age-of-onset Alzheimer's disease (EOAD) and cluster into sub-syndromes (SSy). The aim of this study was to investigate the association between 18 F-FDG-PET regional and connectivity-based brain metabolic dysfunctions and neuropsychiatric SSy. NPSs were assessed in 27 EOAD using the Neuropsychiatric Inventory and further clustered into four SSy (apathetic, hyperactivity, affective, and psychotic SSy). Eighty-five percent of EOAD showed at least one NPS. Voxel-wise correlations between SSy scores and brain glucose metabolism (assessed with 18 F-FDG positron emission tomography) were studied. Interregional correlation analysis was used to explore metabolic connectivity in the salience (aSN) and default mode networks (DMN) in a larger sample of EOAD (N = 51) and Healthy Controls (N = 57). The apathetic, hyperactivity, and affective SSy were highly prevalent (>60%) as compared to the psychotic SSy (33%). The hyperactivity SSy scores were associated with increase of glucose metabolism in frontal and limbic structures, implicated in behavioral control. A comparable positive correlation with part of the same network was found for the affective SSy scores. On the other hand, the apathetic SSy scores were negatively correlated with metabolism in the bilateral orbitofrontal and dorsolateral frontal cortex known to be involved in motivation and decision-making processes. Consistent with these SSy regional correlations with brain metabolic dysfunction, the connectivity analysis showed increases in the aSN and decreases in the DMN. Behavioral abnormalities in EOAD are associated with specific dysfunctional changes in brain metabolic activity, in particular in the aSN that seems to play a crucial role in NPSs in EOAD. Hum Brain Mapp 37:4234-4247, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Tommaso Ballarini
- Università Vita-Salute San Raffaele, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Leonardo Iaccarino
- Università Vita-Salute San Raffaele, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | | | - Nagehan Ayakta
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California
| | - Bruce L Miller
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California
| | - William J Jagust
- Helen Wills Neuroscience Institute, University of California, Berkeley, California
| | - Maria Luisa Gorno-Tempini
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California
| | - Gil D Rabinovici
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California
| | - Daniela Perani
- Università Vita-Salute San Raffaele, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,San Raffaele Hospital, Nuclear Medicine Unit, Milan, Italy
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25
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Chung J, Yoo K, Kim E, Na DL, Jeong Y. Glucose Metabolic Brain Networks in Early-Onset vs. Late-Onset Alzheimer's Disease. Front Aging Neurosci 2016; 8:159. [PMID: 27445800 PMCID: PMC4928512 DOI: 10.3389/fnagi.2016.00159] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/16/2016] [Indexed: 01/02/2023] Open
Abstract
Objective: Early-onset Alzheimer's disease (EAD) shows distinct features from late-onset Alzheimer's disease (LAD). To explore the characteristics of EAD, clinical, neuropsychological, and functional imaging studies have been conducted. However, differences between EAD and LAD are not clear, especially in terms of brain connectivity and networks. In this study, we investigated the differences in metabolic connectivity between EAD and LAD by adopting graph theory measures. Methods: We analyzed 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) images to investigate the distinct features of metabolic connectivity between EAD and LAD. Using metabolic connectivity and graph theory analysis, metabolic network differences between LAD and EAD were explored. Results: Results showed the decreased connectivity centered in the cingulate gyri and occipital regions in EAD, whereas decreased connectivity in the occipital and temporal regions as well as increased connectivity in the supplementary motor area were observed in LAD when compared with age-matched control groups. Global efficiency and clustering coefficients were decreased in EAD but not in LAD. EAD showed progressive network deterioration as a function of disease severity and clinical dementia rating (CDR) scores, mainly in terms of connectivity between the cingulate gyri and occipital regions. Global efficiency and clustering coefficients were also decreased along with disease severity. Conclusion: These results indicate that EAD and LAD have distinguished features in terms of metabolic connectivity, with EAD demonstrating more extensive and progressive deterioration.
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Affiliation(s)
- Jinyong Chung
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea; KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Kwangsun Yoo
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea; KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Eunjoo Kim
- Department of Neurology, School of Medicine and Medical Research Institute, Pusan National University Busan, South Korea
| | - Duk L Na
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of MedicineSeoul, South Korea; Neuroscience Center, Samsung Medical CenterSeoul, South Korea
| | - Yong Jeong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea; KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
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26
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Romero-Garcia R, Atienza M, Cantero JL. Different Scales of Cortical Organization are Selectively Targeted in the Progression to Alzheimer's Disease. Int J Neural Syst 2015; 26:1650003. [PMID: 26790483 DOI: 10.1142/s0129065716500039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Previous studies have shown that the topological organization of the cerebral cortex is altered in Alzheimer's disease (AD). However, it remains unknown whether different levels of the cortical hierarchy are homogeneously affected during disease progression, and which of these levels are mostly involved in the breakdown of metabolic (functional) connectivity. To fulfill these goals, we acquired structural magnetic resonance images (MRI) and positron emission tomography (PET) with the radiotracer 18F-fludeoxyglucose (FDG) in 29 healthy old (HO) adults, 29 amnestic mild cognitive impairment (aMCI) and 29 mild AD patients. Structural and metabolic connections were obtained from inter-regional correlations of cortical thickness and glucose consumption, respectively. Results showed that AD and HO groups differed at all levels of cortical organization (i.e. whole cortex, hemisphere, lobe and node), whereas differences among the three groups were only evident at the lobe and node levels. The correlation between structural and metabolic connectivity (F-S coupling) was also disturbed during AD progression, affecting to different connectivity scales: it decreased at the local level, revealing a progressive increase of metabolic connections in those local communities with fewer structural connections; whereas it increased at the global level, likely due to a parallel reduction of cortical thickness and glucose consumption between long-distance cortical regions. Collectively, these results reveal that different levels of cortical organization are selectively affected during the transition from normal aging to dementia, which could be helpful to track cortical dysfunctions in the progression to AD.
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Affiliation(s)
- Rafael Romero-Garcia
- Laboratory of Functional Neuroscience, Pablo de Olavide University, Seville, Spain
| | - Mercedes Atienza
- Laboratory of Functional Neuroscience, CIBERNED, Pablo de Olavide University, Seville, Spain
| | - Jose L. Cantero
- Laboratory of Functional Neuroscience, CIBERNED, Pablo de Olavide University, Seville, Spain
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27
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Choi H, Choi Y, Kim KW, Kang H, Hwang DW, Kim EE, Chung JK, Lee DS. Maturation of metabolic connectivity of the adolescent rat brain. eLife 2015; 4. [PMID: 26613413 PMCID: PMC4718811 DOI: 10.7554/elife.11571] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/27/2015] [Indexed: 11/30/2022] Open
Abstract
Neuroimaging has been used to examine developmental changes of the brain. While PET studies revealed maturation-related changes, maturation of metabolic connectivity of the brain is not yet understood. Here, we show that rat brain metabolism is reconfigured to achieve long-distance connections with higher energy efficiency during maturation. Metabolism increased in anterior cerebrum and decreased in thalamus and cerebellum during maturation. When functional covariance patterns of PET images were examined, metabolic networks including default mode network (DMN) were extracted. Connectivity increased between the anterior and posterior parts of DMN and sensory-motor cortices during maturation. Energy efficiency, a ratio of connectivity strength to metabolism of a region, increased in medial prefrontal and retrosplenial cortices. Our data revealed that metabolic networks mature to increase metabolic connections and establish its efficiency between large-scale spatial components from childhood to early adulthood. Neurodevelopmental diseases might be understood by abnormal reconfiguration of metabolic connectivity and efficiency. DOI:http://dx.doi.org/10.7554/eLife.11571.001 The brain consumes a great deal of a sugar called glucose, which is delivered to the brain through blood vessels. Active regions of the brain need more glucose, and so the brain has a metabolic network that controls when and where glucose is metabolized. Yet precisely how this metabolic network changes during brain development is not yet understood. Choi et al. have now monitored the patterns of glucose metabolism in the brains of awake rats as they matured from 'childhood' to early adulthood. The experiments involved injecting the rats with radioactive glucose, and then using a technique called positron emission tomography (commonly known as 'PET scan') to monitor the metabolism of these radioactive sugar molecules in the animals’ brains. Choi et al. showed that the patterns of glucose consumption in the brain shift drastically as the rats mature. Importantly, the findings showed that these shifts in glucose metabolism seem to support the activity of long distance connections that develop as the brain matures. The findings also showed that the increased long distance connections were energy efficient. The results suggest that these metabolic changes are likely a way of maintaining high-energy efficiency that is crucial for the brain to perform normally. Finally, in addition to revealing the changes involved in normal brain development, these findings may have implications in neurological and psychiatric disorders in which the brain fails to achieve efficient metabolic networks as it matures. DOI:http://dx.doi.org/10.7554/eLife.11571.002
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Affiliation(s)
- Hongyoon Choi
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Yoori Choi
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyu Wan Kim
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyejin Kang
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Do Won Hwang
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - E Edmund Kim
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - June-Key Chung
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Soo Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
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28
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Carbonell F, Charil A, Zijdenbos AP, Evans AC, Bedell BJ. Hierarchical multivariate covariance analysis of metabolic connectivity. J Cereb Blood Flow Metab 2014; 34:1936-43. [PMID: 25294129 PMCID: PMC4269748 DOI: 10.1038/jcbfm.2014.165] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/23/2014] [Accepted: 09/04/2014] [Indexed: 01/28/2023]
Abstract
Conventional brain connectivity analysis is typically based on the assessment of interregional correlations. Given that correlation coefficients are derived from both covariance and variance, group differences in covariance may be obscured by differences in the variance terms. To facilitate a comprehensive assessment of connectivity, we propose a unified statistical framework that interrogates the individual terms of the correlation coefficient. We have evaluated the utility of this method for metabolic connectivity analysis using [18F]2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study. As an illustrative example of the utility of this approach, we examined metabolic connectivity in angular gyrus and precuneus seed regions of mild cognitive impairment (MCI) subjects with low and high β-amyloid burdens. This new multivariate method allowed us to identify alterations in the metabolic connectome, which would not have been detected using classic seed-based correlation analysis. Ultimately, this novel approach should be extensible to brain network analysis and broadly applicable to other imaging modalities, such as functional magnetic resonance imaging (MRI).
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Affiliation(s)
| | | | | | - Alan C Evans
- 1] Biospective Inc., Montreal, QC, Canada [2] Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Barry J Bedell
- 1] Biospective Inc., Montreal, QC, Canada [2] Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Carbonell F, Charil A, Zijdenbos AP, Evans AC, Bedell BJ. β-Amyloid is associated with aberrant metabolic connectivity in subjects with mild cognitive impairment. J Cereb Blood Flow Metab 2014; 34:1169-79. [PMID: 24736891 DOI: 10.1038/jcbfm.2014.66] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 02/27/2014] [Accepted: 03/25/2014] [Indexed: 01/09/2023]
Abstract
Positron emission tomography (PET) studies using [18F]2-fluoro-2-deoxyglucose (FDG) have identified a well-defined pattern of glucose hypometabolism in Alzheimer's disease (AD). The assessment of the metabolic relationship among brain regions has the potential to provide unique information regarding the disease process. Previous studies of metabolic correlation patterns have demonstrated alterations in AD subjects relative to age-matched, healthy control subjects. The objective of this study was to examine the associations between β-amyloid, apolipoprotein E ɛ4 (APOE ɛ4) genotype, and metabolic correlations patterns in subjects diagnosed with mild cognitive impairment (MCI). Mild cognitive impairment subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study were categorized into β-amyloid-low and β-amyloid-high groups, based on quantitative analysis of [18F]florbetapir PET scans, and APOE ɛ4 non-carriers and carriers based on genotyping. We generated voxel-wise metabolic correlation strength maps across the entire cerebral cortex for each group, and, subsequently, performed a seed-based analysis. We found that the APOE ɛ4 genotype was closely related to regional glucose hypometabolism, while elevated, fibrillar β-amyloid burden was associated with specific derangements of the metabolic correlation patterns.
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Morbelli S, Perneczky R, Drzezga A, Frisoni GB, Caroli A, van Berckel BNM, Ossenkoppele R, Guedj E, Didic M, Brugnolo A, Naseri M, Sambuceti G, Pagani M, Nobili F. Metabolic networks underlying cognitive reserve in prodromal Alzheimer disease: a European Alzheimer disease consortium project. J Nucl Med 2013; 54:894-902. [PMID: 23591639 DOI: 10.2967/jnumed.112.113928] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
UNLABELLED This project aimed to investigate the metabolic basis for resilience to neurodegeneration (cognitive reserve) in highly educated patients with prodromal Alzheimer disease (AD). METHODS Sixty-four patients with amnestic mild cognitive impairment who later converted to AD dementia during follow-up, and 90 controls, underwent brain (18)F-FDG PET. Both groups were divided into a poorly educated subgroup (42 controls and 36 prodromal AD patients) and a highly educated subgroup (48 controls and 28 prodromal AD patients). Brain metabolism was first compared between education-matched groups of patients and controls. Then, metabolism was compared between highly and poorly educated prodromal AD patients in both directions to identify regions of high education-related metabolic depression and compensation. The clusters of significant depression and compensation were further used as volumetric regions of interest (ROIs) in a brain interregional correlation analysis in each prodromal AD subgroup to explore metabolic connectivity. All analyses were performed by means of SPM8 (P < 0.001 uncorrected at peak level, P < 0.05 false discovery rate-corrected at cluster level; age, sex, Mini-Mental State Examination score, and center as nuisance). RESULTS Highly educated prodromal AD patients showed more severe hypometabolism than poorly educated prodromal AD patients in the left inferior and middle temporal gyri and the left middle occipital gyrus (ROI depression). Conversely, they showed relative hypermetabolism in the right inferior, middle, and superior frontal gyri (ROI compensation). The sites of compensation, mainly corresponding to the right dorsolateral prefrontal cortex (DLFC), showed wide metabolic correlations with several cortical areas in both hemispheres (frontotemporal cortex, parahippocampal gyrus, and precuneus) in highly educated prodromal AD patients but not in poorly educated prodromal AD patients. To provide evidence on whether these metabolic correlations represent preservation of the physiologic networks of highly educated control subjects (neural reserve) or rather the recruitment of alternative networks (neural compensation), or a combination of the two, we performed metabolic connectivity analysis of the DLFC in highly educated controls as well. The correlation sites of right DLFC partly overlapped those of highly educated prodromal AD patients but were less extended. CONCLUSION The present findings suggest that highly educated prodromal AD patients can cope better with the disease thanks to neural reserve but also to the recruitment of compensatory neural networks in which the right DLFC plays a key role.
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Affiliation(s)
- Silvia Morbelli
- Nuclear Medicine, Department of Internal Medicine, IRCCS AOU San Martino-IST, University of Genoa, Genoa, Italy.
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