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Huang H, Chen Z, Fan B, Huang D, Qiu Z, Luo C, Zheng J. Abnormal global and local connectivity in patients with anti-N-methyl-D-aspartate receptor encephalitis: A resting-state functional MRI study. Brain Res 2024; 1837:148985. [PMID: 38714228 DOI: 10.1016/j.brainres.2024.148985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 03/27/2024] [Accepted: 05/04/2024] [Indexed: 05/09/2024]
Abstract
OBJECTIVE We decided to investigate the changes of global and local connectivity in anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis patients based on eigenvector centrality (EC) and regional homogeneity (ReHo). We sought new biomarkers to identify the patients based on multivariate pattern analysis (MVPA). METHODS Functional MRI (fMRI) was performed on all participants. EC, ReHo and MVPA were used to analyze the fMRI images. The correlation between the global or local connectivity and neuropsychology tests was detected. RESULTS The MoCA scores of the patients were lower than those of the healthy controls (HCs), while the HAMD24 and HAMA scores of the patients were higher than those of the HCs. Increased EC values in the right calcarine (CAL.R) and decreased EC values in the right putamen (PUT.R) distinguished these subjects with anti-NMDAR encephalitis from HCs. The higher ReHo values in the left postcentral gyrus (PoCG.L) were detected in the patients. The correlation analysis showed that the EC values in the PUT.R were negatively correlated with HAMD24 and HAMA scores, while the ReHo values in the PoCG.L were negatively correlated with MoCA scores. Better classification performance was reached in the EC-based classifier (AUC = 0.80), while weaker classification performance was achieved in the ReHo-based classifier (AUC = 0.74) or the classifier based on EC and ReHo (AUC = 0.74). The brain areas with large weights were located in the frontal lobe, parietal lobe, cerebellum and basal ganglia. CONCLUSION Our findings suggest that abnormal global and local connectivity may play an important part in the pathophysiological mechanism of neuropsychiatric symptoms in the anti-NMDAR encephalitis patients. The EC-based classifier may be better than the ReHo-based classifier in identifying anti-NMDAR encephalitis patients.
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Affiliation(s)
- Huachun Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zexiang Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Binglin Fan
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Dongying Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zhuoyan Qiu
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Cuimi Luo
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jinou Zheng
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China.
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Samson AD, Rajagopal S, Pasvanis S, Villeneuve S, McIntosh AR, Rajah MN. Sex differences in longitudinal changes of episodic memory-related brain activity and cognition in cognitively unimpaired older adults with a family history of Alzheimer's disease. Neuroimage Clin 2023; 40:103532. [PMID: 37931333 PMCID: PMC10652211 DOI: 10.1016/j.nicl.2023.103532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/08/2023]
Abstract
Episodic memory decline is an early symptom of Alzheimer's disease (AD) - a neurodegenerative disease that has a higher prevalence rate in older females compared to older males. However, little is known about why these sex differences in prevalence rate exist. In the current longitudinal task fMRI study, we explored whether there were sex differences in the patterns of memory decline and brain activity during object-location (spatial context) encoding and retrieval in a large sample of cognitively unimpaired older adults from the Pre-symptomatic Evaluation of Novel or Experimental Treatments for Alzheimer's Disease (PREVENT-AD) program who are at heightened risk of developing AD due to having a family history (+FH) of the disease. The goal of the study was to gain insight into whether there are sex differences in the neural correlates of episodic memory decline, which may advance knowledge about sex-specific patterns in the natural progression to AD. Our results indicate that +FH females performed better than +FH males at both baseline and follow-up on neuropsychological and task fMRI measures of episodic memory. Moreover, multivariate data-driven task fMRI analysis identified generalized patterns of longitudinal decline in medial temporal lobe activity that was paralleled by longitudinal increases in lateral prefrontal cortex, caudate and midline cortical activity during successful episodic retrieval and novelty detection in +FH males, but not females. Post-hoc analyses indicated that higher education had a stronger effect on +FH females neuropsychological scores compared to +FH males. We conclude that higher educational attainment may have a greater neuroprotective effect in older +FH females compared to +FH males.
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Affiliation(s)
- Alexandria D Samson
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario M6A 2E1, Canada; Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada
| | - Sricharana Rajagopal
- Centre for Cerebral Imaging, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Stamatoula Pasvanis
- Centre for Cerebral Imaging, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Sylvia Villeneuve
- Centre for Studies on the Prevention of Alzheimer's Disease (StoP-AD), Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada; Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada
| | - Anthony R McIntosh
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario M6A 2E1, Canada; Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada; Institute for Neuroscience and Neurotechnology, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - M Natasha Rajah
- Centre for Cerebral Imaging, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada; Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada; Department of Psychology, Toronto Metropolitan University, Toronto, Ontario M5B 2K3, Canada.
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3
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Grønli OK, Daae Rasmussen I, Aslaksen PM, Bystad M. A four-month home-based tDCS study on patients with Alzheimer's disease. Neurocase 2022; 28:276-282. [PMID: 35852094 DOI: 10.1080/13554794.2022.2100710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In the present open-label study, our first aim was to study the tolerability and feasibility of long-term treatment with transcranial direct current stimulation (tDCS) and the second aim was to measure whether the treatment led to cognitive improvement. Participants with AD used a tDCS home-treatment kit inducing a low current (2 mA) via two scalp electrodes 30 minutes daily for 4 months. A total of 8 participants were recruited. The treatment technique was manageable for the participants and their spouses, and no troublesome side effects were reported. No significant effects of treatment were found after 4 months.
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Affiliation(s)
- Ole K Grønli
- Division of Mental Health and Substance Abuse, University Hospital of North Norway, Tromsø, Norway.,Department of Clinical Medicine, Faculty of Health Science, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Ingrid Daae Rasmussen
- Division of Mental Health and Substance Abuse, University Hospital of North Norway, Tromsø, Norway
| | - Per M Aslaksen
- Department of Psychology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Martin Bystad
- Division of Mental Health and Substance Abuse, University Hospital of North Norway, Tromsø, Norway
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4
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Lee ES, Youn H, Hyung WSW, Suh S, Han CE, Eo JS, Jeong HG. The effects of cerebral amyloidopathy on regional glucose metabolism in older adults with depression and mild cognitive impairment while performing memory tasks. Eur J Neurosci 2021; 54:6663-6672. [PMID: 34528336 DOI: 10.1111/ejn.15461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
Co-occurring depression and mild cognitive impairment (MCI) in older adults are important because they have a high risk of conversion to dementia. In the present study, task-related F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) was used to analyse older adults with concomitant depression and MCI. We recruited 20 older adults with simultaneous depression and MCI and 10 older adults with normal cognition (NC). The Verbal Paired Associates test and digit span test were used for the task-related FDG-PET. The 20 older adults with depression and MCI were classified into two groups based on the F-18 florbetaben PET results: depressed MCI patients with (LLD-MCI-A[+]; n = 11) and without amyloid accumulation (LLD-MCI-A[-]; n = 9). Reduced regional cerebral glucose metabolism (rCMglc) in the left superior frontal region was observed in the LLD-MCI-A(-) group compared with the NC group. Analyses of the NC and LLD-MCI-A(+) groups showed significantly decreased rCMglc in the right inferior parietal and left middle frontal regions in the LLD-MCI-A(+) group. rCMglc in the left precuneus was lower in the LLD-MCI-A(+) group than in the LLD-MCI-A(-) group. Significant correlations between the rCMglc in the right inferior parietal/left precuneus regions and memory task scores were observed based on correlation analyses of NC and LLD-MCI-A(+) groups. The findings in the present study indicate the presence of amyloid accumulation influences glucose metabolism in depressed elderly subjects with MCI while performing cognitive tasks. Task-related FDG-PET examinations may help differentiate MCI associated with depression from comorbid depression in patients with prodromal Alzheimer's disease.
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Affiliation(s)
- Eun Seong Lee
- Department of Nuclear Medicine, Korea University Guro Hospital, Seoul, South Korea
| | - HyunChul Youn
- Department of Psychiatry, Soonchunhyang University Bucheon Hospital, Bucheon, South Korea
| | | | - Sangil Suh
- Department of Radiology, Korea University Guro Hospital, Seoul, South Korea
| | - Cheol E Han
- Department of Electronics and Information Engineering, Korea University, Sejong, South Korea
| | - Jae Seon Eo
- Department of Nuclear Medicine, Korea University Guro Hospital, Seoul, South Korea
| | - Hyun-Ghang Jeong
- Department of Psychiatry, Korea University Guro Hospital, Seoul, South Korea.,Korea University Research Institute of Mental Health, Seoul, South Korea
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5
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Abnormal cortical regions and subsystems in whole brain functional connectivity of mild cognitive impairment and Alzheimer's disease: a preliminary study. Aging Clin Exp Res 2021; 33:367-381. [PMID: 32277436 DOI: 10.1007/s40520-020-01539-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 03/24/2020] [Indexed: 12/12/2022]
Abstract
The disease roots of Alzheimer's disease (AD) are unknown. Functional connection (FC) methodology based on functional MRI data is an effective lever to investigate macroscopic neural activity patterns. However, regional properties of brain architecture have been less investigated by special markers of graph indexes in general mental disorders. In terms of the set of the abnormal edges in the FCs matrix, this paper introduces the strength index (S-scores) of region centrality on the principle of holism. Then, the important process is to investigate the S-scores of regions and subsystems in 36 healthy controls, 38 mild cognitive impairment (MCI) patients and 34 AD patients. At the edge level, abnormal FCs is numerically increasing progressively from MCI to AD brains. At the region level, the CUN.L, PAL.R, THA.L, and TPOsup.R regions are highlighted with abnormal S-scores in MCI patients. By comparison, more regions are abnormal in AD patients, which are PreCG.L, INS.R, DCG.L, AMYG.R, IOG.R, FFG.L, PoCG.L, PCUN.R, TPOsup.L, MTG.L, and TPOmid.L. Importantly, the regions in DMN have abnormal S-scores in AD groups. At the module level, the S-scores of frontal, parietal, occipital lobe, and cerebellum are found in MCI and AD patients. Meanwhile, the abnormal lateralization is inferred because of the S-scores of left and top hemisphere in the AD group. Though this is strictly a contrastive study, the S-score may be a meaningful imaging marker for excavating AD psychopathology.
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6
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Hector A, Brouillette J. Hyperactivity Induced by Soluble Amyloid-β Oligomers in the Early Stages of Alzheimer's Disease. Front Mol Neurosci 2021; 13:600084. [PMID: 33488358 PMCID: PMC7817907 DOI: 10.3389/fnmol.2020.600084] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022] Open
Abstract
Soluble amyloid-beta oligomers (Aβo) start to accumulate in the human brain one to two decades before any clinical symptoms of Alzheimer's disease (AD) and are implicated in synapse loss, one of the best predictors of memory decline that characterize the illness. Cognitive impairment in AD was traditionally thought to result from a reduction in synaptic activity which ultimately induces neurodegeneration. More recent evidence indicates that in the early stages of AD synaptic failure is, at least partly, induced by neuronal hyperactivity rather than hypoactivity. Here, we review the growing body of evidence supporting the implication of soluble Aβo on the induction of neuronal hyperactivity in AD animal models, in vitro, and in humans. We then discuss the impact of Aβo-induced hyperactivity on memory performance, cell death, epileptiform activity, gamma oscillations, and slow wave activity. We provide an overview of the cellular and molecular mechanisms that are emerging to explain how Aβo induce neuronal hyperactivity. We conclude by providing an outlook on the impact of hyperactivity for the development of disease-modifying interventions at the onset of AD.
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Affiliation(s)
- Audrey Hector
- Department of Pharmacology and Physiology, Hôpital du Sacré-Cœur de Montréal Research Center, Centre intégré universitaire de santé et de services sociaux du Nord-de-l'Île-de-Montréal (CIUSSS-NIM), Université de Montréal, Montreal, QC, Canada
| | - Jonathan Brouillette
- Department of Pharmacology and Physiology, Hôpital du Sacré-Cœur de Montréal Research Center, Centre intégré universitaire de santé et de services sociaux du Nord-de-l'Île-de-Montréal (CIUSSS-NIM), Université de Montréal, Montreal, QC, Canada
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7
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Turriziani P, Smirni D, Mangano GR, Zappalà G, Giustiniani A, Cipolotti L, Oliveri M. Low-Frequency Repetitive Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex Enhances Recognition Memory in Alzheimer's Disease. J Alzheimers Dis 2020; 72:613-622. [PMID: 31609693 DOI: 10.3233/jad-190888] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND The lack of effective pharmacological or behavioral interventions for memory impairments associated with Alzheimer's disease (AD) emphasizes the need for the investigation of approaches based on neuromodulation. OBJECTIVE This study examined the effects of inhibitory repetitive transcranial magnetic stimulation (rTMS) of prefrontal cortex on recognition memory in AD patients. METHODS In a first experiment, 24 mild AD patients received sham and real 1Hz rTMS over the left and right dorsolateral prefrontal cortex (DLPFC), in different sessions, between encoding and retrieval phases of a non-verbal recognition memory task. In a second experiment, another group of 14 AD patients underwent sham controlled repeated sessions of 1Hz rTMS of the right DLPFC across a two week treatment. Non-verbal recognition memory task was performed at baseline, at the end of the two weeks period and at a follow up of 1 month. RESULTS Right real rTMS significantly improved memory performance compared to right sham rTMS (p = 0.001). Left real rTMS left the memory performance unchanged as compared with left sham rTMS (p = 0.46). The two sham conditions did not differ between each other (p = 0.24). In the second experiment, AD patients treated with real rTMS showed an improvement of memory performance at the end of the two weeks treatment (p = 0.0009), that persisted at 1-month follow-up (p = 0.002). CONCLUSION These findings provide evidence that inhibitory rTMS over the right DLPFC can improve recognition memory function in AD patients. They also suggest the importance of a new approach of non-invasive brain stimulation as a promising treatment in AD.
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Affiliation(s)
- Patrizia Turriziani
- Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy.,NeuroTeam Life and Science, Palermo, Italy
| | - Daniela Smirni
- Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy.,NeuroTeam Life and Science, Palermo, Italy
| | - Giuseppa Renata Mangano
- Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy.,NeuroTeam Life and Science, Palermo, Italy
| | - Giuseppe Zappalà
- Unità di Neurologia Cognitiva e Riabilitazione, ARNAS Garibaldi, Catania, Italy
| | - Andreina Giustiniani
- Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy.,NEUROFARBA Department, University of Firenze, Firenze, Italy
| | - Lisa Cipolotti
- Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Massimiliano Oliveri
- Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy.,NeuroTeam Life and Science, Palermo, Italy
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8
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Resting state functional connectivity abnormalities and delayed recall performance in patients with amnestic mild cognitive impairment. Brain Imaging Behav 2020; 14:267-277. [PMID: 30421086 DOI: 10.1007/s11682-018-9974-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amnestic Mild Cognitive Impairment (aMCI) represents the transition between healthy aging and Alzheimer's dementia (AD) wherein gradual impairment of cognitive abilities, especially memory sets in. Impairment in episodic memory, especially delayed recall, is a hallmark of AD and therefore, patients with aMCI with more severe impairment in episodic memory are considered to be at greater risk of imminent conversion to AD. Brain structural and functional abnormalities were examined by comparing gray matter volumes, white matter micro-structural integrity and resting state functional connectivity (rsFC), between patients with aMCI (n = 46) having lower vs. higher episodic memory delayed recall (EM-DR) performance scores, correcting the influences of age, sex, number of years of formal education and total brain volumes using voxel-based morphometry, whole-brain tract based spatial statistics and dual regression analysis respectively. 'Low' performers (n = 27) when compared to 'high' performers (n = 19) showed significantly increased rsFC in the dorsal attention network (DAN) and central executive network (CEN) in the absence of demonstrable gray matter volumetric or white matter micro-structural integrity differences at family-wise error (FWE) corrected (p < 0.05) significance threshold. Follow-up data available for 38 (low performers = 22; high performers = 16) of the above 46 subjects (82.60% follow-up rate) over a median follow-up period of 24.5 months revealed that 7 subjects (18.42%) had converted to dementia. These converted subjects included 5 of the 22 low performers (22.72%) and 2 of the 16 high performers (12.5%) within the follow-up sample (n = 38). The results of the study indicate that imminent conversion of aMCI to dementia is higher in low performers in comparison to high performers, which may be characterized by increased rsFC in task positive networks, viz., DAN and CEN, as opposed to gray or white matter structural changes. This finding, therefore, might be considered as a prognostic indicator of progression from aMCI to dementia.
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9
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McDonough IM, Festini SB, Wood MM. Risk for Alzheimer's disease: A review of long-term episodic memory encoding and retrieval fMRI studies. Ageing Res Rev 2020; 62:101133. [PMID: 32717407 DOI: 10.1016/j.arr.2020.101133] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/21/2020] [Accepted: 07/18/2020] [Indexed: 02/06/2023]
Abstract
Many risk factors have been identified that predict future progression to Alzheimer's disease (AD). However, clear links have yet to be made between these risk factors and how they affect brain functioning in early stages of AD. We conducted a narrative review and a quantitative analysis to better understand the relationship between nine categories of AD risk (i.e., brain pathology, genetics/family history, vascular health, head trauma, cognitive decline, engagement in daily life, late-life depression, sex/gender, and ethnoracial group) and task-evoked fMRI activity during episodic memory in cognitively-normal older adults. Our narrative review revealed widespread regional alterations of both greater and lower brain activity with AD risk. Nevertheless, our quantitative analysis revealed that a subset of studies converged on two patterns: AD risk was associated with (1) greater brain activity in frontal and parietal regions, but (2) reduced brain activity in hippocampal and occipital regions. The brain regions affected depended on the assessed memory stage (encoding or retrieval). Although the results clearly indicate that AD risks impact brain activity, we caution against using fMRI as a diagnostic tool for AD at the current time because the above consistencies were present among much variability, even among the same risk factor.
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Affiliation(s)
- Ian M McDonough
- Department of Psychology, The University of Alabama, BOX 870348, Tuscaloosa, AL 35487, USA.
| | - Sara B Festini
- Department of Psychology, University of Tampa, 401 W Kennedy Blvd. Tampa, FL 33606, USA
| | - Meagan M Wood
- Department of Psychology, Valdosta State University, 1500 N. Patterson Street, Valdosta, GA 31698, USA
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10
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Xiang J, Wang X, Gao Y, Li T, Cao R, Yan T, Ma Y, Niu Y, Xue J, Wang B. Phosphodiesterase 4D Gene Modifies the Functional Network of Patients With Mild Cognitive Impairment and Alzheimer's Disease. Front Genet 2020; 11:890. [PMID: 32849849 PMCID: PMC7423997 DOI: 10.3389/fgene.2020.00890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is affected by several genetic variants. It has been demonstrated that genetic variants affect brain organization and function. In this study, using whole genome-wide association studies (GWAS), we analyzed the functional magnetic resonance imaging and genetic data from the Alzheimer’s Disease Neuroimaging Initiative dataset (ADNI) dataset and identified genetic variants associated with the topology of the functional brain network http://www.adni-info.org. We found three novel loci (rs2409627, rs9647533, and rs11955845) in an intron of the phosphodiesterase 4D (PDE4D) gene that contribute to abnormalities in the topological organization of the functional network. In particular, compared to the wild-type genotype, the subjects carrying the PDE4D variants had altered network properties, including a significantly reduced clustering coefficient, small-worldness, global and local efficiency, a significantly enhanced path length and a normalized path length. In addition, we found that all global brain network attributes were affected by PDE4D variants to different extents as the disease progressed. Additionally, brain regions with alterations in nodal efficiency due to the variations in PDE4D were predominant in the limbic lobe, temporal lobe and frontal lobes. PDE4D has a great effect on memory consolidation and cognition through long-term potentiation (LTP) effects and/or the promotion of inflammatory effects. PDE4D variants might be a main reasons underlyling for the abnormal topological properties and cognitive impairment. Furthermore, we speculated that PDE4D is a risk factor for neural degenerative diseases and provided important clues for the earlier detection and therapeutic intervention for AD.
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Affiliation(s)
- Jie Xiang
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Xin Wang
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Yuan Gao
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Ting Li
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Rui Cao
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Ting Yan
- Translational Medicine Research Center, Shanxi Medical University, Taiyuan, China
| | - Yunxiao Ma
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Yan Niu
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Jiayue Xue
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Bin Wang
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
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11
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Moore EE, Liu D, Pechman KR, Acosta LMY, Bell SP, Davis LT, Blennow K, Zetterberg H, Landman BA, Schrag MS, Hohman TJ, Gifford KA, Jefferson AL. Mild Cognitive Impairment Staging Yields Genetic Susceptibility, Biomarker, and Neuroimaging Differences. Front Aging Neurosci 2020; 12:139. [PMID: 32581762 PMCID: PMC7289958 DOI: 10.3389/fnagi.2020.00139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 04/27/2020] [Indexed: 01/22/2023] Open
Abstract
Introduction While Alzheimer’s disease (AD) is divided into severity stages, mild cognitive impairment (MCI) remains a solitary construct despite clinical and prognostic heterogeneity. This study aimed to characterize differences in genetic, cerebrospinal fluid (CSF), neuroimaging, and neuropsychological markers across clinician-derived MCI stages. Methods Vanderbilt Memory & Aging Project participants with MCI were categorized into 3 severity subtypes at screening based on neuropsychological assessment, functional assessment, and Clinical Dementia Rating interview, including mild (n = 18, 75 ± 8 years), moderate (n = 89 72 ± 7 years), and severe subtypes (n = 18, 78 ± 8 years). At enrollment, participants underwent neuropsychological testing, 3T brain magnetic resonance imaging (MRI), and optional fasting lumbar puncture to obtain CSF. Neuropsychological testing and MRI were repeated at 18-months, 3-years, and 5-years with a mean follow-up time of 3.3 years. Ordinary least square regressions examined cross-sectional associations between MCI severity and apolipoprotein E (APOE)-ε4 status, CSF biomarkers of amyloid beta (Aβ), phosphorylated tau, total tau, and synaptic dysfunction (neurogranin), baseline neuroimaging biomarkers, and baseline neuropsychological performance. Longitudinal associations between baseline MCI severity and neuroimaging and neuropsychological trajectory were assessed using linear mixed effects models with random intercepts and slopes and a follow-up time interaction. Analyses adjusted for baseline age, sex, race/ethnicity, education, and intracranial volume for MRI models. Results Stages differed at baseline on APOE-ε4 status (early < middle = late; p-values < 0.03) and CSF Aβ (early > middle = late), phosphorylated and total tau (early = middle < late; p-values < 0.05), and neurogranin concentrations (early = middle < late; p-values < 0.05). MCI stage related to greater longitudinal cognitive decline, hippocampal atrophy, and inferior lateral ventricle dilation (early < late; p-values < 0.03). Discussion Clinician staging of MCI severity yielded longitudinal cognitive trajectory and structural neuroimaging differences in regions susceptible to AD neuropathology and neurodegeneration. As expected, participants with more severe MCI symptoms at study entry had greater cognitive decline and gray matter atrophy over time. Differences are likely attributable to baseline differences in amyloidosis, tau, and synaptic dysfunction. MCI staging may provide insight into underlying pathology, prognosis, and therapeutic targets.
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Affiliation(s)
- Elizabeth E Moore
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Dandan Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Kimberly R Pechman
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Lealani Mae Y Acosta
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Susan P Bell
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States.,Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - L Taylor Davis
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom.,UK Dementia Research Institute at UCL, London, United Kingdom
| | - Bennett A Landman
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States.,Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, United States
| | - Matthew S Schrag
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Timothy J Hohman
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States.,Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Katherine A Gifford
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Angela L Jefferson
- Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States.,Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
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12
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Inhibitory Parvalbumin Basket Cell Activity is Selectively Reduced during Hippocampal Sharp Wave Ripples in a Mouse Model of Familial Alzheimer's Disease. J Neurosci 2020; 40:5116-5136. [PMID: 32439703 DOI: 10.1523/jneurosci.0425-20.2020] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/07/2020] [Accepted: 05/18/2020] [Indexed: 12/29/2022] Open
Abstract
Memory disruption in mild cognitive impairment (MCI) and Alzheimer's disease (AD) is poorly understood, particularly at early stages preceding neurodegeneration. In mouse models of AD, there are disruptions to sharp wave ripples (SWRs), hippocampal population events with a critical role in memory consolidation. However, the microcircuitry underlying these disruptions is under-explored. We tested whether a selective reduction in parvalbumin-expressing (PV) inhibitory interneuron activity underlies hyperactivity and SWR disruption. We employed the 5xFAD model of familial AD crossed with mouse lines labeling excitatory pyramidal cells (PCs) and inhibitory PV cells. We observed a 33% increase in frequency, 58% increase in amplitude, and 8% decrease in duration of SWRs in ex vivo slices from male and female three-month 5xFAD mice versus littermate controls. 5xFAD mice of the same age were impaired in a hippocampal-dependent memory task. Concurrent with SWR recordings, we performed calcium imaging, cell-attached, and whole-cell recordings of PC and PV cells within the CA1 region. PCs in 5xFAD mice participated in enlarged ensembles, with superficial PCs (sPCs) having a higher probability of spiking during SWRs. Both deep PCs (dPCs) and sPCs displayed an increased synaptic E/I ratio, suggesting a disinhibitory mechanism. In contrast, we observed a 46% spike rate reduction during SWRs in PV basket cells (PVBCs), while PV bistratified and axo-axonic cells were unimpaired. Excitatory synaptic drive to PVBCs was selectively reduced by 50%, resulting in decreased E/I ratio. Considering prior studies of intrinsic PV cell dysfunction in AD, these findings suggest alterations to the PC-PVBC microcircuit also contribute to impairment.SIGNIFICANCE STATEMENT We demonstrate that a specific subtype of inhibitory neuron, parvalbumin-expressing (PV) basket cells, have selectively reduced activity in a model of Alzheimer's disease (AD) during activity critical for the consolidation of memory. These results identify a potential cellular target for therapeutic intervention to restore aberrant network activity in early amyloid pathology. While PV cells have previously been identified as a potential therapeutic target, this study for the first time recognizes that other PV neuronal subtypes, including bistratified and axo-axonic cells, are spared. These experiments are the first to record synaptic and spiking activity during sharp wave ripple (SWR) events in early amyloid pathology and reveal that a selective decrease in excitatory synaptic drive to PV basket cells (PVBCs) likely underlies reduced function.
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13
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Aganj I, Frau-Pascual A, Iglesias JE, Yendiki A, Augustinack JC, Salat DH, Fischl B. COMPENSATORY BRAIN CONNECTION DISCOVERY IN ALZHEIMER'S DISEASE. PROCEEDINGS. IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING 2020; 2020:283-287. [PMID: 32587665 PMCID: PMC7316404 DOI: 10.1109/isbi45749.2020.9098440] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Identification of the specific brain networks that are vulnerable or resilient in neurodegenerative diseases can help to better understand the disease effects and derive new connectomic imaging biomarkers. In this work, we use brain connectivity to find pairs of structural connections that are negatively correlated with each other across Alzheimer's disease (AD) and healthy populations. Such anti-correlated brain connections can be informative for identification of compensatory neuronal pathways and the mechanism of brain networks' resilience to AD. We find significantly anti-correlated connections in a public diffusion-MRI database, and then validate the results on other databases.
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Affiliation(s)
- Iman Aganj
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology
| | - Aina Frau-Pascual
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
| | - Juan E Iglesias
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology
- Center for Medical Image Computing (CMIC), University College London, London, UK
| | - Anastasia Yendiki
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
| | - Jean C Augustinack
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
| | - David H Salat
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
| | - Bruce Fischl
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology
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14
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Tosi G, Borsani C, Castiglioni S, Daini R, Franceschi M, Romano D. Complexity in neuropsychological assessments of cognitive impairment: A network analysis approach. Cortex 2020; 124:85-96. [DOI: 10.1016/j.cortex.2019.11.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/29/2019] [Accepted: 11/08/2019] [Indexed: 12/12/2022]
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15
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Dafni-Merom A, Peters-Founshtein G, Kahana-Merhavi S, Arzy S. A unified brain system of orientation and its disruption in Alzheimer's disease. Ann Clin Transl Neurol 2019; 6:2468-2478. [PMID: 31738022 PMCID: PMC6917329 DOI: 10.1002/acn3.50940] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/17/2019] [Indexed: 01/01/2023] Open
Abstract
Objective To investigate whether a unified brain system manages one’s orientation to different places, events and people in one’s environment, and test the hypothesis that failure of this system (disorientation) is an early sign of Alzheimer’s disease (AD). Methods A total of 46 participants (patients along the AD continuum and cognitively normal control subjects) were tested in a personalized, ecologically valid task of orientation relating to the participant’s own world in space, time and person under high–density electroencephalography. As a first step, we used evoked potential mapping to search for brain topography correlated with participants’ performance in orientating themselves to different places (space), events (time) and people (person) (Experiment 1). We then compared behavioral and electrophysiological changes in patients along the AD continuum (Experiment 2). Results We identified a specific brain topography (“orientation map”) that was active for orientation in space, time and person in correlation to participants’ performance. Both performance and the map’s strength gradually decreased from health to mild cognitive impairment (MCI) and from MCI to AD. Another map, immediately preceding the orientation map, showed the longest activity in patients with MCI, significantly more than both patients with AD and cognitively normal controls. Interpretation Our findings demonstrate that the same brain topography accounts for orientation in the different domains of space, time and person and provide a nexus between deterioration in patients’ orientation with the aggravation of Alzheimer’s disease.
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Affiliation(s)
- Amnon Dafni-Merom
- Neuropsychiatry Laboratory, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Neurology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Gregory Peters-Founshtein
- Neuropsychiatry Laboratory, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Neurology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | | | - Shahar Arzy
- Neuropsychiatry Laboratory, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Neurology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
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16
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Aguirre N, Costumero V, Marin-Marin L, Escudero J, Belloch V, Parcet MA, Ávila C. Activity in Memory Brain Networks During Encoding Differentiates Mild Cognitive Impairment Converters from Non-Converters. J Alzheimers Dis 2019; 71:1049-1061. [DOI: 10.3233/jad-190421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Naiara Aguirre
- Department of Basic and Clinical Psychology and Psychobiology, Jaume I University, Castelló de la Plana, Spain
| | - Víctor Costumero
- Department of Basic and Clinical Psychology and Psychobiology, Jaume I University, Castelló de la Plana, Spain
- Center for Brain and Cognition, Pompeu Fabra University, Barcelona, Spain
| | - Lidón Marin-Marin
- Department of Basic and Clinical Psychology and Psychobiology, Jaume I University, Castelló de la Plana, Spain
| | - Joaquín Escudero
- Department of Neurology, General Hospital of Valencia, Valencia, Spain
| | | | - María Antonia Parcet
- Department of Basic and Clinical Psychology and Psychobiology, Jaume I University, Castelló de la Plana, Spain
| | - César Ávila
- Department of Basic and Clinical Psychology and Psychobiology, Jaume I University, Castelló de la Plana, Spain
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17
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Fide E, Emek-Savaş DD, Aktürk T, Güntekin B, Hanoğlu L, Yener GG. Electrophysiological evidence of altered facial expressions recognition in Alzheimer's disease: A comprehensive ERP study. Clin Neurophysiol 2019; 130:1813-1824. [PMID: 31401490 DOI: 10.1016/j.clinph.2019.06.229] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 05/24/2019] [Accepted: 06/18/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The present study aims to evaluate the amplitude and latency of event-related potentials (ERPs) P100, N170, VPP and N230 in individuals with Alzheimer's disease (AD) compared to healthy elderly controls, using a passive viewing task of emotional facial expressions. METHODS Twenty-four individuals with mild to moderate AD and 23 demographically matched healthy elderly controls were included in the study. ERP P100, N170, VPP and N230 amplitude and latency values were compared between groups. RESULTS The categorization of emotional facial expressions was intact; yet, increased P100 amplitude and latency, decreased N170 amplitude, and increased VPP amplitude were observed in AD compared to controls. Increased N230 amplitude and latency were observed in response to angry expressions, while neutral expressions elicited decreased amplitude and latency. CONCLUSIONS Increased P100 amplitude and latency may reflect reduced amygdala volume and disruptions in the visual system, while decreased N170 and increased VPP amplitudes may reflect impaired perceptual processing, mitigated by a greater involvement of prefrontal areas for task performance in AD. SIGNIFICANCE This study is the first to report a complex pattern of ERPs to emotional facial expressions in individuals with AD.
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Affiliation(s)
- Ezgi Fide
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey
| | - Derya Durusu Emek-Savaş
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey; Department of Psychology, Dokuz Eylul University, Izmir, Turkey; Atlantic Fellow for Equity in Brain Health at the Global Brain Health Institute (GBHI), Trinity College Dublin, Dublin, Ireland.
| | - Tuba Aktürk
- Istanbul Medipol University, Vocational School, Program of Electroneurophysiology, Istanbul, Turkey; Istanbul Medipol University, Graduate School of Health Sciences, Department of Neuroscience, Istanbul, Turkey
| | - Bahar Güntekin
- Istanbul Medipol University, International School of Medicine, Department of Biophysics, Istanbul, Turkey; REMER, Clinical Electrophysiology, Neuroimaging and Neuromodulation Lab, Istanbul Medipol University, Istanbul, Turkey
| | - Lütfü Hanoğlu
- REMER, Clinical Electrophysiology, Neuroimaging and Neuromodulation Lab, Istanbul Medipol University, Istanbul, Turkey; Istanbul Medipol University, School of Medicine, Department of Neurology, Istanbul, Turkey
| | - Görsev G Yener
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey; Dokuz Eylul University Medical School, Department of Neurology, Izmir, Turkey; Dokuz Eylul University, Brain Dynamics Multidisciplinary Research Center, Izmir, Turkey
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18
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Richter N, Beckers N, Onur OA, Dietlein M, Tittgemeyer M, Kracht L, Neumaier B, Fink GR, Kukolja J. Effect of cholinergic treatment depends on cholinergic integrity in early Alzheimer's disease. Brain 2019; 141:903-915. [PMID: 29309600 DOI: 10.1093/brain/awx356] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/08/2017] [Indexed: 02/04/2023] Open
Abstract
In early Alzheimer's disease, which initially presents with progressive loss of short-term memory, neurodegeneration especially affects cholinergic neurons of the basal forebrain. Pharmacotherapy of Alzheimer's disease therefore often targets the cholinergic system. In contrast, cholinergic pharmacotherapy of mild cognitive impairment is debated since its efficacy to date remains controversial. We here investigated the relationship between cholinergic treatment effects and the integrity of the cholinergic system in mild cognitive impairment due to Alzheimer's disease. Fourteen patients with high likelihood of mild cognitive impairment due to Alzheimer's disease and 16 age-matched cognitively normal adults performed an episodic memory task during functional magnetic resonance imaging under three conditions: (i) without pharmacotherapy; (ii) with placebo; and (iii) with a single dose of rivastigmine (3 mg). Cortical acetylcholinesterase activity was measured using PET with the tracer 11C-N-methyl-4-piperidyl acetate (MP4A). Cortical acetylcholinesterase activity was significantly decreased in patients relative to controls, especially in the lateral temporal lobes. Without pharmacotherapy, mild cognitive impairment was associated with less memory-related neural activation in the fusiform gyrus and impaired deactivation in the posterior cingulate cortex, relative to controls. These differences were attenuated under cholinergic stimulation with rivastigmine: patients showed increased neural activation in the right fusiform gyrus but enhanced deactivation of the posterior cingulate cortex under rivastigmine, compared to placebo. Conversely, controls showed reduced activation of the fusiform gyrus and reduced deactivation of the posterior cingulate under rivastigmine, compared to placebo. In both groups, the change in neural activation in response to rivastigmine was negatively associated with local acetylcholinesterase activity. At the behavioural level, an analysis of covariance revealed a significant group × treatment interaction in episodic memory performance when accounting for hippocampal grey matter atrophy and function. Our results indicate that rivastigmine differentially affects memory-related neural activity in patients with mild cognitive impairment and cognitively normal, age-matched adults, depending on acetylcholinesterase activity as a marker for the integrity of the cortical cholinergic system. Furthermore, hippocampal integrity showed an independent association with the response of memory performance to acetylcholinesterase inhibition.
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Affiliation(s)
- Nils Richter
- Department of Neurology, University Hospital Cologne, 50937 Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, 52425 Jülich, Germany.,Max-Planck-Institute for Metabolism Research, 50937 Cologne, Germany
| | - Nora Beckers
- Department of Neurology, University Hospital Cologne, 50937 Cologne, Germany
| | - Oezguer A Onur
- Department of Neurology, University Hospital Cologne, 50937 Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, 52425 Jülich, Germany
| | - Markus Dietlein
- Department of Nuclear Medicine, University Hospital Cologne, 50937 Cologne, Germany
| | - Marc Tittgemeyer
- Max-Planck-Institute for Metabolism Research, 50937 Cologne, Germany
| | - Lutz Kracht
- Max-Planck-Institute for Metabolism Research, 50937 Cologne, Germany.,Department of Nuclear Medicine, University Hospital Cologne, 50937 Cologne, Germany
| | - Bernd Neumaier
- Nuclear Chemistry, Institute of Neuroscience and Medicine (INM-5), Research Center Jülich, 52425 Jülich, Germany.,Institute for Radiochemistry and Experimental Molecular Imaging, University Hospital Cologne, 50937 Cologne, Germany
| | - Gereon R Fink
- Department of Neurology, University Hospital Cologne, 50937 Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, 52425 Jülich, Germany
| | - Juraj Kukolja
- Department of Neurology, University Hospital Cologne, 50937 Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, 52425 Jülich, Germany
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19
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Zott B, Busche MA, Sperling RA, Konnerth A. What Happens with the Circuit in Alzheimer's Disease in Mice and Humans? Annu Rev Neurosci 2019; 41:277-297. [PMID: 29986165 DOI: 10.1146/annurev-neuro-080317-061725] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A major mystery of many types of neurological and psychiatric disorders, such as Alzheimer's disease (AD), remains the underlying, disease-specific neuronal damage. Because of the strong interconnectivity of neurons in the brain, neuronal dysfunction necessarily disrupts neuronal circuits. In this article, we review evidence for the disruption of large-scale networks from imaging studies of humans and relate it to studies of cellular dysfunction in mouse models of AD. The emerging picture is that some forms of early network dysfunctions can be explained by excessively increased levels of neuronal activity. The notion of such neuronal hyperactivity receives strong support from in vivo and in vitro cellular imaging and electrophysiological recordings in the mouse, which provide mechanistic insights underlying the change in neuronal excitability. Overall, some key aspects of AD-related neuronal dysfunctions in humans and mice are strikingly similar and support the continuation of such a translational strategy.
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Affiliation(s)
- Benedikt Zott
- Institute of Neuroscience, Technical University of Munich, 80802 Munich, Germany; .,Center for Integrated Protein Sciences, Technical University of Munich, 80802 Munich, Germany.,Munich Cluster for Systems Neurology, Technical University of Munich, 80802 Munich, Germany
| | - Marc Aurel Busche
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Reisa A Sperling
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.,Department of Neurology and Center for Alzheimer Research and Treatment, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.,Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Arthur Konnerth
- Institute of Neuroscience, Technical University of Munich, 80802 Munich, Germany; .,Center for Integrated Protein Sciences, Technical University of Munich, 80802 Munich, Germany.,Munich Cluster for Systems Neurology, Technical University of Munich, 80802 Munich, Germany
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20
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Simon-Vermot L, Taylor ANW, Araque Caballero MÀ, Franzmeier N, Buerger K, Catak C, Janowitz D, Kambeitz-Ilankovic LM, Ertl-Wagner B, Duering M, Ewers M. Correspondence Between Resting-State and Episodic Memory-Task Related Networks in Elderly Subjects. Front Aging Neurosci 2018; 10:362. [PMID: 30467476 PMCID: PMC6236026 DOI: 10.3389/fnagi.2018.00362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 10/22/2018] [Indexed: 11/14/2022] Open
Abstract
Resting-state fMRI studies demonstrated temporally synchronous fluctuations in brain activity among ensembles of brain regions, suggesting the existence of intrinsic functional networks. A spatial match between some of the resting-state networks and regional brain activation during cognitive tasks has been noted, suggesting that resting-state networks support particular cognitive abilities. However, the spatial match and predictive value of any resting-state network and regional brain activation during episodic memory is only poorly understood. In order to address this research gap, we obtained fMRI acquired both during rest and a face-name association task in 38 healthy elderly subjects. In separate independent component analyses, networks of correlated brain activity during rest or the episodic memory task were identified. For the independent components identified for task-based fMRI, the design matrix of successful encoding or retrieval trials was regressed against the time course of each of the component to identify significantly activated networks. Spatial regression was used to assess the match of resting-state networks against those related to successful memory encoding or retrieval. We found that resting-state networks covering the medial temporal, middle temporal, and frontal areas showed increased activity during successful encoding. Resting-state networks located within posterior brain regions showed increased activity during successful recognition. However, the level of resting-state network connectivity was not predictive of the task-related activity in these networks. These results suggest that a circumscribed number of functional networks detectable during rest become engaged during successful episodic memory. However, higher intrinsic connectivity at rest may not translate into higher network expression during episodic memory.
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Affiliation(s)
- Lee Simon-Vermot
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | | | - Miguel À Araque Caballero
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | - Nicolai Franzmeier
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | - Katharina Buerger
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany
| | - Cihan Catak
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | - Daniel Janowitz
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | | | - Birgit Ertl-Wagner
- Institute for Clinical Radiology, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | - Marco Duering
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | - Michael Ewers
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
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21
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Bayram E, Caldwell JZK, Banks SJ. Current understanding of magnetic resonance imaging biomarkers and memory in Alzheimer's disease. ALZHEIMERS & DEMENTIA-TRANSLATIONAL RESEARCH & CLINICAL INTERVENTIONS 2018; 4:395-413. [PMID: 30229130 PMCID: PMC6140335 DOI: 10.1016/j.trci.2018.04.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Alzheimer's disease (AD) is caused by a cascade of changes to brain integrity. Neuroimaging biomarkers are important in diagnosis and monitoring the effects of interventions. As memory impairments are among the first symptoms of AD, the relationship between imaging findings and memory deficits is important in biomarker research. The most established magnetic resonance imaging (MRI) finding is hippocampal atrophy, which is related to memory decline and currently used as a diagnostic criterion for AD. While the medial temporal lobes are impacted early by the spread of neurofibrillary tangles, other networks and regional changes can be found quite early in the progression. Atrophy in several frontal and parietal regions, cortical thinning, and white matter alterations correlate with memory deficits in early AD. Changes in activation and connectivity have been detected by functional MRI (fMRI). Task-based fMRI studies have revealed medial temporal lobe hypoactivation, parietal hyperactivation, and frontal hyperactivation in AD during memory tasks, and activation patterns of these regions are also altered in preclinical and prodromal AD. Resting state fMRI has revealed alterations in default mode network activity related to memory in early AD. These studies are limited in part due to the historic inclusion of patients who had suspected AD but likely did not have the disorder. Modern biomarkers allow for more diagnostic certainty, allowing better understanding of neuroimaging markers in true AD, even in the preclinical stage. Larger patient cohorts, comparison of candidate imaging biomarkers to more established biomarkers, and inclusion of more detailed neuropsychological batteries to assess multiple aspects of memory are needed to better understand the memory deficit in AD and help develop new biomarkers. This article reviews MRI findings related to episodic memory impairments in AD and introduces a new study with multimodal imaging and comprehensive neuropsychiatric evaluation to overcome current limitations.
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Affiliation(s)
- Ece Bayram
- Department of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA
| | - Jessica Z K Caldwell
- Department of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA
| | - Sarah J Banks
- Department of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA
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22
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Liu X, Chen X, Zheng W, Xia M, Han Y, Song H, Li K, He Y, Wang Z. Altered Functional Connectivity of Insular Subregions in Alzheimer's Disease. Front Aging Neurosci 2018; 10:107. [PMID: 29695961 PMCID: PMC5905235 DOI: 10.3389/fnagi.2018.00107] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/29/2018] [Indexed: 11/15/2022] Open
Abstract
Recent researches have demonstrated that the insula is the crucial hub of the human brain networks and most vulnerable region of Alzheimer’s disease (AD). However, little is known about the changes of functional connectivity of insular subregions in the AD patients. In this study, we collected resting-state functional magnetic resonance imaging (fMRI) data including 32 AD patients and 38 healthy controls (HCs). By defining three subregions of insula, we mapped whole-brain resting-state functional connectivity (RSFC) and identified several distinct RSFC patterns of the insular subregions: For positive connectivity, three cognitive-related RSFC patterns were identified within insula that suggest anterior-to-posterior functional subdivisions: (1) an dorsal anterior zone of the insula that exhibits RSFC with executive control network (ECN); (2) a ventral anterior zone of insula, exhibits functional connectivity with the salience network (SN); (3) a posterior zone along the insula exhibits functional connectivity with the sensorimotor network (SMN). In addition, we found significant negative connectivities between the each insular subregion and several special default mode network (DMN) regions. Compared with controls, the AD patients demonstrated distinct disruption of positive RSFCs in the different network (ECN and SMN), suggesting the impairment of the functional integrity. There were no differences of the positive RSFCs in the SN between the two groups. On the other hand, several DMN regions showed increased negative RSFCs to the sub-region of insula in the AD patients, indicating compensatory plasticity. Furthermore, these abnormal insular subregions RSFCs are closely correlated with cognitive performances in the AD patients. Our findings suggested that different insular subregions presented distinct RSFC patterns with various functional networks, which are differently affected in the AD patients.
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Affiliation(s)
- Xingyun Liu
- Department of Radiology, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Xiaodan Chen
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China.,International Data Group (IDG)/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Weimin Zheng
- Department of Radiology, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Mingrui Xia
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China.,International Data Group (IDG)/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Ying Han
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Haiqing Song
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China.,International Data Group (IDG)/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Zhiqun Wang
- Department of Radiology, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China.,Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
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23
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Altered functional brain networks in amnestic mild cognitive impairment: a resting-state fMRI study. Brain Imaging Behav 2018; 11:619-631. [PMID: 26972578 DOI: 10.1007/s11682-016-9539-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Amnestic mild cognitive impairment MCI (aMCI) has a high progression to Alzheimer's disease (AD). Recently, resting-state functional MRI (RS-fMRI) has been increasingly utilized in studying the pathogenesis of aMCI, especially in resting-state networks (RSNs). In the current study, we aimed to explore abnormal RSNs related to memory deficits in aMCI patients compared to the aged-matched healthy control group using RS-fMRI techniques. Firstly, we used ALFF (amplitude of low-frequency fluctuation) method to define the regions of interest (ROIs) which exhibited significant changes in aMCI compared with the control group. Then, we divided these ROIs into different networks in line with prior studies. The aim of this study is to explore the functional connectivity between these ROIs within networks and also to investigate the connectivity between networks. Comparing aMCI to the control group, our results showed that 1) the hippocampus (HIPP) had decreased FC with the medial prefrontal cortex (mPFC) and inferior parietal lobe (IPL), and the mPFC showed increased connectivity to IPL in the default mode network; 2) the thalamus showed decreased FC with the putamen and HIPP, and the HIPP showed increased connectivity to the putamen in the limbic system; 3) the supplementary motor area had decreased FC with the middle temporal gyrus and increased FC with the superior parietal lobe in the sensorimotor network; 4) increased connectivity between the lingual gyrus and middle occipital gyrus in the visual network; and 5) the DMN has reduced inter-network connectivities with the SMN and VN. These findings indicated that functional brain networks involved in cognition such as episodic memory, sensorimotor and visual cognition in aMCI were altered, and provided a new sight in understanding the important subtype of aMCI.
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24
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Polcher A, Frommann I, Koppara A, Wolfsgruber S, Jessen F, Wagner M. Face-Name Associative Recognition Deficits in Subjective Cognitive Decline and Mild Cognitive Impairment. J Alzheimers Dis 2018; 56:1185-1196. [PMID: 28106560 DOI: 10.3233/jad-160637] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND There is a need for more sensitive neuropsychological tests to detect subtle cognitive deficits emerging in the preclinical stage of Alzheimer's disease (AD). Associative memory is a cognitive function supported by the hippocampus and affected early in the process of AD. OBJECTIVE We developed a short computerized face-name associative recognition test (FNART) and tested whether it would detect memory impairment in memory clinic patients with mild cognitive impairment (MCI) and subjective cognitive decline (SCD). METHODS We recruited 61 elderly patients with either SCD (n = 32) or MCI (n = 29) and 28 healthy controls (HC) and compared performance on FNART, self-reported cognitive deterioration in different domains (ECog-39), and, in a reduced sample (n = 46), performance on the visual Paired Associates Learning of the CANTAB battery. RESULTS A significant effect of group on FNART test performance in the total sample was found (p < 0.001). Planned contrasts indicated a significantly lower associative memory performance in the SCD (p = 0.001, d = 0.82) and MCI group (p < 0.001, d = 1.54), as compared to HCs, respectively. The CANTAB-PAL discriminated only between HC and MCI, possibly because of reduced statistical power. Adjusted for depression, performance on FNART was significantly related to ECog-39 Memory in SCD patients (p = 0.024) but not in MCI patients. CONCLUSIONS Associative memory is substantially impaired in memory clinic patients with SCD and correlates specifically with memory complaints at this putative preclinical stage of AD. Further studies will need to examine the predictive validity of the FNART in SCD patients with regard to longitudinal (i.e., conversion to MCI/AD) and biomarker outcomes.
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Affiliation(s)
- Alexandra Polcher
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Psychiatry, University of Bonn, Germany
| | - Ingo Frommann
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Psychiatry, University of Bonn, Germany
| | - Alexander Koppara
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Psychiatry, University of Bonn, Germany
| | - Steffen Wolfsgruber
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Psychiatry, University of Bonn, Germany
| | - Frank Jessen
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Psychiatry, University of Cologne, Germany
| | - Michael Wagner
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Psychiatry, University of Bonn, Germany
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25
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Liu H, Zhang L, Xi Q, Zhao X, Wang F, Wang X, Men W, Lin Q. Changes in Brain Lateralization in Patients with Mild Cognitive Impairment and Alzheimer's Disease: A Resting-State Functional Magnetic Resonance Study from Alzheimer's Disease Neuroimaging Initiative. Front Neurol 2018; 9:3. [PMID: 29472886 PMCID: PMC5810419 DOI: 10.3389/fneur.2018.00003] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/03/2018] [Indexed: 11/13/2022] Open
Abstract
Purpose To detect changes in brain lateralization in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) using resting-state functional magnetic resonance imaging (fMRI). Materials and methods Data from 61 well-matched right-handed subjects were obtained from the Alzheimer’s Disease Neuroimaging Initiative, including 19 healthy controls (HCs), 25 patients with MCI, and 17 patients with AD. First, we divided 256 pairs of seed regions from each hemisphere covering the entire cerebral gray matter. Then, we used the intrinsic laterality index (iLI) approach to quantify the functional laterality using fMRI. One-way ANOVA was employed to estimate the differences in iLI among the three groups. The sum, number and mean value of the iLI were calculated within the thresholds of 0 < |iLI| < 0.2, 0.2 ≤ |iLI| < 0.4, 0.4 ≤ |iLI| < 0.8, and |iLI| ≥ 0.8, to explore the changes in the lateralization of resting-state brain function in patients with MCI and AD. Results One-way ANOVA revealed that the iLIs of the three groups were significantly different. The HCs showed a significant leftward interhemispheric difference within |iLI| ≥ 0.8. Compared with the HCs, the patients with MCI manifested a distinct abnormal rightward interhemispheric asymmetry, mainly within the thresholds of 0.2 ≤ |iLI| < 0.4 and 0.4 ≤ |iLI| < 0.8; in the patients with AD, the normal leftward lateralization that was observed in the HCs disappeared, and an abnormal rightward laterality was expressed within 0.4 ≤ |iLI| < 0.8. By directly comparing the patients with MCI with the patients with AD, an exclusive abnormal rightward laterality was observed in the patients with MCI within the 0.2 ≤ |iLI| < 0.4 threshold, and the normal leftward asymmetry vanished in the patients with AD within the |iLI| ≥ 0.8 threshold. Conclusion Global brain lateralization was different among three groups. The abnormal rightward dominance observed in the patients with MCI and AD may indicate that these patients use additional brain resources to compensate for the loss of cognitive function, and the observed disappearance of the leftward laterality in the patients with AD was likely associated with the damage in the left hemisphere. The observed disappearance of the rightward asymmetry in the patients with AD using the 0.2 ≤ |iLI| < 0.4 threshold was likely a sign of decompensation. Our study provides new insights that may improve our understanding of MCI and AD.
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Affiliation(s)
- Hao Liu
- Tongji University School of Medicine, Shanghai, China
| | - Lele Zhang
- Department of Imaging, Changping District Hospital, Beijing, China
| | - Qian Xi
- Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaohu Zhao
- Department of Imaging, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.,Department of Imaging, Shanghai TongJi Hospital, Shanghai, China
| | - Fei Wang
- Department of Neurosurgery, Shanghai TongJi Hospital, Shanghai, China
| | - Xiangbin Wang
- Department of Imaging, Shanghai TongJi Hospital, Shanghai, China
| | - Weiwei Men
- Institute of Heavy Ion Physics, Peking University, Beijing, China.,Center for MRI Research, Beijing Key Laboratory for Medical Physics and Engineering, Beijing, China
| | - Qixiang Lin
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
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26
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Rajmohan R, Anderson RC, Fang D, Meyer AG, Laengvejkal P, Julayanont P, Hannabas G, Linton K, Culberson J, Khan H, De Toledo J, Reddy PH, O'Boyle MW. Lower Activation in Frontal Cortex and Posterior Cingulate Cortex Observed during Sex Determination Test in Early-Stage Dementia of the Alzheimer Type. Front Aging Neurosci 2017; 9:156. [PMID: 28588478 PMCID: PMC5438965 DOI: 10.3389/fnagi.2017.00156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 05/05/2017] [Indexed: 11/13/2022] Open
Abstract
Face-labeling refers to the ability to classify faces into social categories. This plays a critical role in human interaction as it serves to define concepts of socially acceptable interpersonal behavior. The purpose of the current study was to characterize, what, if any, impairments in face-labeling are detectable in participants with early-stage clinically diagnosed dementia of the Alzheimer type (CDDAT) through the use of the sex determination test (SDT). In the current study, four (1 female, 3 males) CDDAT and nine (4 females, 5 males) age-matched neurotypicals (NT) completed the SDT using chimeric faces while undergoing BOLD fMRI. It was expected that CDDAT participants would have poor verbal fluency, which would correspond to poor performance on the SDT. This could be explained by decreased activation and connectivity patterns within the fusiform face area (FFA) and anterior cingulate cortex (ACC). DTI was also performed to test the association of pathological deterioration of connectivity in the uncinate fasciculus (UF) and verbally-mediated performance. CDDAT showed lower verbal fluency test (VFT) performance, but VFT was not significantly correlated to SDT and no significant difference was seen between CDDAT and NT for SDT performance as half of the CDDAT performed substantially worse than NT while the other half performed similarly. BOLD fMRI of SDT displayed differences in the left superior frontal gyrus and posterior cingulate cortex (PCC), but not the FFA or ACC. Furthermore, although DTI showed deterioration of the right inferior and superior longitudinal fasciculi, as well as the PCC, it did not demonstrate significant deterioration of UF tracts. Taken together, early-stage CDDAT may represent a common emerging point for the loss of face labeling ability.
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Affiliation(s)
- Ravi Rajmohan
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Ronald C Anderson
- Department of Electrical and Computer Engineering, Texas Tech UniversityLubbock, TX, United States
| | - Dan Fang
- Department of Human Development and Family Studies, Texas Tech UniversityLubbock, TX, United States
| | - Austin G Meyer
- School of Medicine, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Pavis Laengvejkal
- Department of Neurology, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Parunyou Julayanont
- Department of Neurology, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Greg Hannabas
- Department of Public Health, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Kitten Linton
- Department of Family Medicine, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - John Culberson
- Department of Family Medicine, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Hafiz Khan
- Department of Public Health, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - John De Toledo
- Department of Neurology, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - P Hemachandra Reddy
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences CenterLubbock, TX, United States.,Garrison Institute on Aging, Texas Tech University Health Sciences CenterLubbock, TX, United States.,Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX, United States.,Department of Speech, Language and Hearing Sciences, Texas Tech University Health Sciences CenterLubbock, TX, United States
| | - Michael W O'Boyle
- Department of Human Development and Family Studies, Texas Tech UniversityLubbock, TX, United States
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27
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Wang Z, Dai Z, Shu H, Liao X, Yue C, Liu D, Guo Q, He Y, Zhang Z. APOE Genotype Effects on Intrinsic Brain Network Connectivity in Patients with Amnestic Mild Cognitive Impairment. Sci Rep 2017; 7:397. [PMID: 28341847 PMCID: PMC5428452 DOI: 10.1038/s41598-017-00432-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 02/20/2017] [Indexed: 12/03/2022] Open
Abstract
Whether and how the apolipoprotein E (APOE) ε4 genotype specifically modulates brain network connectivity in patients with amnestic mild cognitive impairment (aMCI) remain largely unknown. Here, we employed resting-state (‘task-free’) functional MRI and network centrality approaches to investigate local (degree centrality, DC) and global (eigenvector centrality, EC) functional integrity in the whole-brain connectome in 156 older adults, including 66 aMCI patients (27 ε4-carriers and 39 non-carriers) and 90 healthy controls (45 ε4-carriers and 45 non-carriers). We observed diagnosis-by-genotype interactions on DC in the left superior/middle frontal gyrus, right middle temporal gyrus and cerebellum, with higher values in the ε4-carriers than non-carriers in the aMCI group. We further observed diagnosis-by-genotype interactions on EC, with higher values in the right middle temporal gyrus but lower values in the medial parts of default-mode network in the ε4-carriers than non-carriers in the aMCI group. Notably, these genotype differences in DC or EC were absent in the control group. Finally, the network connectivity DC values were negatively correlated with cognitive performance in the aMCI ε4-carriers. Our findings suggest that the APOE genotype selectively modulates the functional integration of brain networks in patients with aMCI, thus providing important insight into the gene-connectome interaction in this disease.
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Affiliation(s)
- Zan Wang
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, China
| | - Zhengjia Dai
- Department of Psychology, Sun Yat-sen University, Guangzhou, 510006, China.,State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China
| | - Hao Shu
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, China
| | - Xuhong Liao
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China
| | - Chunxian Yue
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, China
| | - Duan Liu
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, China
| | - Qihao Guo
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China.
| | - Zhijun Zhang
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, China.
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28
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Pereira L, Airan RD, Fishman A, Pillai JJ, Kansal K, Onyike CU, Prince JL, Ying SH, Sair HI. Resting-state functional connectivity and cognitive dysfunction correlations in spinocerebelellar ataxia type 6 (SCA6). Hum Brain Mapp 2017; 38:3001-3010. [PMID: 28295805 DOI: 10.1002/hbm.23568] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 02/28/2017] [Accepted: 03/03/2017] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE The aim of this study is to evaluate the correlation between resting state functional MRI (RS-fMRI) activity and motor and cognitive impairment in spinocerebellar ataxia type 6 (SCA6). METHODS Twelve patients with genetically confirmed SCA6 and 14 age matched healthy controls were imaged with RS-fMRI. Whole brain gray matter was automatically parcellated into 1000 regions of interest (ROIs). For each ROI, the first eigenvariate of voxel time courses was extracted. For each patient, Pearson correlation coefficients between each pair of ROI time courses were calculated across the 1000 ROIs. The set of average control correlation coefficients were fed as an undirected weighted adjacency matrix into the Rubinov and Sporns (2010) modularity algorithm. The intranetwork global efficiency of the thresholded adjacency sub-matrix was calculated and correlated with ataxia scores and cognitive performance. RESULTS SCA6 patients showed mild cognitive impairments in executive function and visual-motor processing compared to control subjects. These neuropsychological impairments were correlated with decreased RS functional connectivity (FC) in the attention network. CONCLUSIONS Mild cognitive executive functions and visual-motor coordination impairments seen in SCA6 patients correlate with decreased resting-state connectivity in the attention network, suggesting a possible metric for the study of cognitive dysfunction in cerebellar disease. Hum Brain Mapp 38:3001-3010, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Licia Pereira
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Raag D Airan
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Ann Fishman
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Jay J Pillai
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Kalyani Kansal
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Chiadi U Onyike
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Jerry L Prince
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Sarah H Ying
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
| | - Haris I Sair
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287
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29
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Rajmohan R, Anderson RC, Fang D, Meyer AG, Laengvejkal P, Julayanont P, Hannabas G, Linton K, Culberson J, Khan HMR, De Toledo J, Reddy PH, O'Boyle M. White Matter Deterioration May Foreshadow Impairment of Emotional Valence Determination in Early-Stage Dementia of the Alzheimer Type. Front Aging Neurosci 2017; 9:37. [PMID: 28298891 PMCID: PMC5331035 DOI: 10.3389/fnagi.2017.00037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/10/2017] [Indexed: 11/13/2022] Open
Abstract
In Alzheimer Disease (AD), non-verbal skills often remain intact for far longer than verbally mediated processes. Four (1 female, 3 males) participants with early-stage Clinically Diagnosed Dementia of the Alzheimer Type (CDDAT) and eight neurotypicals (NTs; 4 females, 4 males) completed the emotional valence determination test (EVDT) while undergoing BOLD functional magnetic resonance imaging (fMRI). We expected CDDAT participants to perform just as well as NTs on the EVDT, and to display increased activity within the bilateral amygdala and right anterior cingulate cortex (r-ACC). We hypothesized that such activity would reflect an increased reliance on these structures to compensate for on-going neuronal loss in frontoparietal regions due to the disease. We used diffusion tensor imaging (DTI) to determine if white matter (WM) damage had occurred in frontoparietal regions as well. CDDAT participants had similar behavioral performance and no differences were observed in brain activity or connectivity patterns within the amygdalae or r-ACC. Decreased fractional anisotropy (FA) values were noted, however, for the bilateral superior longitudinal fasciculi and posterior cingulate cortex (PCC). We interpret these findings to suggest that emotional valence determination and non-verbal skill sets are largely intact at this stage of the disease, but signs foreshadowing future decline were revealed by possible WM deterioration. Understanding how non-verbal skill sets are altered, while remaining largely intact, offers new insights into how non-verbal communication may be more successfully implemented in the care of AD patients and highlights the potential role of DTI as a presymptomatic biomarker.
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Affiliation(s)
- Ravi Rajmohan
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - Ronald C Anderson
- Department of Electrical and Computer Engineering, Texas Tech University Lubbock, TX, USA
| | - Dan Fang
- Department of Human Development and Family Studies, Texas Tech University Lubbock, TX, USA
| | - Austin G Meyer
- School of Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - Pavis Laengvejkal
- Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - Parunyou Julayanont
- Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - Greg Hannabas
- Department of Public Health, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - Kitten Linton
- Department of Family Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - John Culberson
- Department of Family Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - Hafiz M R Khan
- Department of Public Health, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - John De Toledo
- Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA
| | - P Hemachandra Reddy
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences CenterLubbock, TX, USA; Garrison Institute on Aging, Texas Tech University Health Sciences CenterLubbock, TX, USA; Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX, USA; Speech, Language and Hearing Sciences, Texas Tech University Health Sciences CenterLubbock, TX, USA
| | - Michael O'Boyle
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences CenterLubbock, TX, USA; Department of Human Development and Family Studies, Texas Tech UniversityLubbock, TX, USA
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30
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Parra-Damas A, Chen M, Enriquez-Barreto L, Ortega L, Acosta S, Perna JC, Fullana MN, Aguilera J, Rodríguez-Alvarez J, Saura CA. CRTC1 Function During Memory Encoding Is Disrupted in Neurodegeneration. Biol Psychiatry 2017; 81:111-123. [PMID: 27587263 DOI: 10.1016/j.biopsych.2016.06.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 05/31/2016] [Accepted: 06/21/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Associative memory impairment is an early clinical feature of dementia patients, but the molecular and cellular mechanisms underlying these deficits are largely unknown. In this study, we investigated the functional regulation of the cyclic adenosine monophosphate response element binding protein (CREB)-regulated transcription coactivator 1 (CRTC1) by associative learning in physiological and neurodegenerative conditions. METHODS We evaluated the activation of CRTC1 in the hippocampus of control mice and mice lacking the Alzheimer's disease-linked presenilin genes (presenilin conditional double knockout [PS cDKO]) after one-trial contextual fear conditioning by using biochemical, immunohistochemical, and gene expression analyses. PS cDKO mice display classical features of neurodegeneration occurring in Alzheimer's disease including age-dependent cortical atrophy, neuron loss, dendritic degeneration, and memory deficits. RESULTS Context-associative learning, but not single context or unconditioned stimuli, induces rapid dephosphorylation (Ser151) and translocation of CRTC1 from the cytosol/dendrites to the nucleus of hippocampal neurons in the mouse brain. Accordingly, context-associative learning induces differential CRTC1-dependent transcription of c-fos and the nuclear receptor subfamily 4 (Nr4a) genes Nr4a1-3 in the hippocampus through a mechanism that involves CRTC1 recruitment to CRE promoters. Deregulation of CRTC1 dephosphorylation, nuclear translocation, and transcriptional function are associated with long-term contextual memory deficits in PS cDKO mice. Importantly, CRTC1 gene therapy in the hippocampus ameliorates context memory and transcriptional deficits and dendritic degeneration despite ongoing cortical degeneration in this neurodegeneration mouse model. CONCLUSIONS These findings reveal a critical role of CRTC1 in the hippocampus during associative memory, and provide evidence that CRTC1 deregulation underlies memory deficits during neurodegeneration.
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Affiliation(s)
- Arnaldo Parra-Damas
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Meng Chen
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Lilian Enriquez-Barreto
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Laura Ortega
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the
| | - Sara Acosta
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the
| | - Judith Camats Perna
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the
| | - M Neus Fullana
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the
| | - José Aguilera
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - José Rodríguez-Alvarez
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Carlos A Saura
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular; and the; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona, Spain.
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31
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Reggev N, Bein O, Maril A. Distinct Neural Suppression and Encoding Effects for Conceptual Novelty and Familiarity. J Cogn Neurosci 2016; 28:1455-70. [DOI: 10.1162/jocn_a_00994] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Abstract
Like yin and yang, novelty and familiarity are typically described as separate-yet-complementary aspects of an experience, two ends of a single continuum. However, novelty and familiarity are also multifaceted. For instance, novelty can sometimes result in enhanced mnemonic performance, whereas at other times familiarity is better remembered. As previous investigations focused primarily on the experimental aspect of novelty, the mechanisms supporting conceptual novelty (the novel combination of two previously unrelated existing concepts) remain unclear. Importantly, conceptual novelty can be recognized as such only when compared with preexperimental familiar knowledge, regardless of experimental status. Here we applied a combined repetition suppression/subsequent memory fMRI paradigm, focusing on the conceptual aspect of novelty and familiarity as the subject matter. Conceptual novelty was characterized by sustained neural activity; familiarity, on the other hand, exhibited repetition effects in multiple cortical regions, a subset of which was modulated by successful encoding. Subsequent memory of novelty was associated only with activation differences in a distinct set of regions, including the hippocampus and medial cortical regions. These results suggest that conceptual novelty (a) does not (easily) trigger the repetition suppression phenomenon but requires sustained neural recruitment and (b) activates dedicated encoding mechanisms. Conceptual familiarity, in contrast, allows rapid neural processing that depends upon existing neural representations. Overall, these findings challenge the definition of novelty as a unitary concept. Furthermore, they bear important implications for research into the neural bases of knowledge representation and recognition memory.
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Montagne A, Nation DA, Pa J, Sweeney MD, Toga AW, Zlokovic BV. Brain imaging of neurovascular dysfunction in Alzheimer's disease. Acta Neuropathol 2016; 131:687-707. [PMID: 27038189 PMCID: PMC5283382 DOI: 10.1007/s00401-016-1570-0] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 11/29/2022]
Abstract
Neurovascular dysfunction, including blood-brain barrier (BBB) breakdown and cerebral blood flow (CBF) dysregulation and reduction, are increasingly recognized to contribute to Alzheimer's disease (AD). The spatial and temporal relationships between different pathophysiological events during preclinical stages of AD, including cerebrovascular dysfunction and pathology, amyloid and tau pathology, and brain structural and functional changes remain, however, still unclear. Recent advances in neuroimaging techniques, i.e., magnetic resonance imaging (MRI) and positron emission tomography (PET), offer new possibilities to understand how the human brain works in health and disease. This includes methods to detect subtle regional changes in the cerebrovascular system integrity. Here, we focus on the neurovascular imaging techniques to evaluate regional BBB permeability (dynamic contrast-enhanced MRI), regional CBF changes (arterial spin labeling- and functional-MRI), vascular pathology (structural MRI), and cerebral metabolism (PET) in the living human brain, and examine how they can inform about neurovascular dysfunction and vascular pathophysiology in dementia and AD. Altogether, these neuroimaging approaches will continue to elucidate the spatio-temporal progression of vascular and neurodegenerative processes in dementia and AD and how they relate to each other.
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Affiliation(s)
- Axel Montagne
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Daniel A Nation
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Judy Pa
- Department of Neurology, Institute for Neuroimaging and Informatics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Melanie D Sweeney
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Arthur W Toga
- Department of Neurology, Institute for Neuroimaging and Informatics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA.
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Topological Properties of Large-Scale Cortical Networks Based on Multiple Morphological Features in Amnestic Mild Cognitive Impairment. Neural Plast 2016; 2016:3462309. [PMID: 27057360 PMCID: PMC4781996 DOI: 10.1155/2016/3462309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 12/20/2015] [Accepted: 12/30/2015] [Indexed: 11/21/2022] Open
Abstract
Previous studies have demonstrated that amnestic mild cognitive impairment (aMCI) has disrupted properties of large-scale cortical networks based on cortical thickness and gray matter volume. However, it is largely unknown whether the topological properties of cortical networks based on geometric measures (i.e., sulcal depth, curvature, and metric distortion) change in aMCI patients compared with normal controls because these geometric features of cerebral cortex may be related to its intrinsic connectivity. Here, we compare properties in cortical networks constructed by six different morphological features in 36 aMCI participants and 36 normal controls. Six cortical features (3 volumetric and 3 geometric features) were extracted for each participant, and brain abnormities in aMCI were identified by cortical network based on graph theory method. All the cortical networks showed small-world properties. Regions showing significant differences mainly located in the medial temporal lobe and supramarginal and right inferior parietal lobe. In addition, we also found that the cortical networks constructed by cortical thickness and sulcal depth showed significant differences between the two groups. Our results indicated that geometric measure (i.e., sulcal depth) can be used to construct network to discriminate individuals with aMCI from controls besides volumetric measures.
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Tromp D, Dufour A, Lithfous S, Pebayle T, Després O. Episodic memory in normal aging and Alzheimer disease: Insights from imaging and behavioral studies. Ageing Res Rev 2015; 24:232-62. [PMID: 26318058 DOI: 10.1016/j.arr.2015.08.006] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/20/2015] [Indexed: 12/30/2022]
Abstract
Age-related cognitive changes often include difficulties in retrieving memories, particularly those that rely on personal experiences within their temporal and spatial contexts (i.e., episodic memories). This decline may vary depending on the studied phase (i.e., encoding, storage or retrieval), according to inter-individual differences, and whether we are talking about normal or pathological (e.g., Alzheimer disease; AD) aging. Such cognitive changes are associated with different structural and functional alterations in the human neural network that underpins episodic memory. The prefrontal cortex is the first structure to be affected by age, followed by the medial temporal lobe (MTL), the parietal cortex and the cerebellum. In AD, however, the modifications occur mainly in the MTL (hippocampus and adjacent structures) before spreading to the neocortex. In this review, we will present results that attempt to characterize normal and pathological cognitive aging at multiple levels by integrating structural, behavioral, inter-individual and neuroimaging measures of episodic memory.
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Affiliation(s)
- D Tromp
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA - UMR 7364 - CNRS/UDS) - 21 rue Becquerel, 67087 Strasbourg, France.
| | - A Dufour
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA - UMR 7364 - CNRS/UDS) - 21 rue Becquerel, 67087 Strasbourg, France; Centre d'Investigations Neurocognitives et Neurophysiologiques (CI2N - UMS 3489 - CNRS/UDS) - 21 rue Becquerel, 67087 Strasbourg, France
| | - S Lithfous
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA - UMR 7364 - CNRS/UDS) - 21 rue Becquerel, 67087 Strasbourg, France
| | - T Pebayle
- Centre d'Investigations Neurocognitives et Neurophysiologiques (CI2N - UMS 3489 - CNRS/UDS) - 21 rue Becquerel, 67087 Strasbourg, France
| | - O Després
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA - UMR 7364 - CNRS/UDS) - 21 rue Becquerel, 67087 Strasbourg, France.
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Janik R, Thomason LAM, Chaudhary S, Dorr A, Scouten A, Schwindt G, Masellis M, Stanisz GJ, Black SE, Stefanovic B. Attenuation of functional hyperemia to visual stimulation in mild Alzheimer's disease and its sensitivity to cholinesterase inhibition. Biochim Biophys Acta Mol Basis Dis 2015; 1862:957-65. [PMID: 26521151 DOI: 10.1016/j.bbadis.2015.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/21/2015] [Accepted: 10/25/2015] [Indexed: 01/09/2023]
Abstract
Despite the growing recognition of the significance of cerebrovascular impairment in the etiology and progression of Alzheimer's disease (AD), the early stage brain vascular dysfunction and its sensitivity to pharmacological interventions is still not fully characterized. Due to the early and aggressive treatment of probable AD with cholinesterase inhibitors (ChEI), which in and of themselves have direct effects on brain vasculature, the vast majority of hemodynamic measurements in early AD subjects reported hitherto have consequently been made only after the start of treatment, complicating the disentanglement of disease- vs. treatment-related effects on the cerebral vasculature. To address this gap, we used pseudo continuous arterial spin labeling MRI to measure resting perfusion and visual stimulation elicited changes in cerebral blood flow (CBF) and blood oxygenation dependent (BOLD) fMRI signal in a cohort of mild AD patients immediately prior to, 6months post, and 12months post commencement of open label cholinesterase inhibitor treatment. Although patients exhibited no gray matter atrophy prior to treatment and their resting perfusion was not distinguishable from that in age, education and gender-matched controls, the patients' visual stimulation-elicited changes in BOLD fMRI and blood flow were decreased by 10±4% (BOLD) and 23±2% (CBF), relative to those in controls. Induction of cholinesterase inhibition treatment was associated with a further, 7±2% reduction in patients' CBF response to visual stimulation, but it stabilized, at this new lower level, over the follow-up period. Likewise, MMSE scores remained stable during the treatment; furthermore, higher MMSE scores were associated with higher perfusion responses to visual stimulation. This study represents the initial step in disentangling the effects of AD pathology from those of the first line treatment with cholinesterase inhibitors on cerebral hemodynamics and supports the use of arterial spin labeling MRI for quantitative evaluation of the brain vascular function in mild Alzheimer's disease. The findings provide evidence of a pronounced deficit in the visual cortex hyperemia despite the relative sparing of visual function in early stage AD, its reduction with ChEI treatment induction, and its stabilization in the first year of cholinesterase inhibition treatment. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.
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Affiliation(s)
- Rafal Janik
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada.
| | - Lynsie A M Thomason
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Simone Chaudhary
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada
| | - Adrienne Dorr
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Amy Scouten
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada
| | - Graeme Schwindt
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Mario Masellis
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Greg J Stanisz
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada; Department of Nerurosurgery and Pediatrics Neurosurgery, Medical University of Lublin, Aleje Raclawickie 1, 20-059 Lublin, Poland
| | - Sandra E Black
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Institute of Medical Sciences, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Medicine (Neurology), Sunnybrook Health Sciences Centre University of Toronto, Canada; Canadian Partnership for Stroke Recovery Sunnybrook Site, Canada
| | - Bojana Stefanovic
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada; Canadian Partnership for Stroke Recovery Sunnybrook Site, Canada
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36
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Wang P, Zhou B, Yao H, Zhan Y, Zhang Z, Cui Y, Xu K, Ma J, Wang L, An N, Zhang X, Liu Y, Jiang T. Aberrant intra- and inter-network connectivity architectures in Alzheimer's disease and mild cognitive impairment. Sci Rep 2015; 5:14824. [PMID: 26439278 PMCID: PMC4594099 DOI: 10.1038/srep14824] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/04/2015] [Indexed: 01/21/2023] Open
Abstract
Alzheimer’s disease (AD) patients and those with high-risk mild cognitive impairment are increasingly considered to have dysfunction syndromes. Large-scale network studies based on neuroimaging techniques may provide additional insight into AD pathophysiology. The aim of the present study is to evaluate the impaired network functional connectivity with the disease progression. For this purpose, we explored altered functional connectivities based on previously well-defined brain areas that comprise the five key functional systems [the default mode network (DMN), dorsal attention network (DAN), control network (CON), salience network (SAL), sensorimotor network (SMN)] in 35 with AD and 27 with mild cognitive impairment (MCI) subjects, compared with 27 normal cognitive subjects. Based on three levels of analysis, we found that intra- and inter-network connectivity were impaired in AD. Importantly, the interaction between the sensorimotor and attention functions was first attacked at the MCI stage and then extended to the key functional systems in the AD individuals. Lower cognitive ability (lower MMSE scores) was significantly associated with greater reductions in intra- and inter-network connectivity across all patient groups. These profiles indicate that aberrant intra- and inter-network dysfunctions might be potential biomarkers or predictors of AD progression and provide new insight into AD pathophysiology.
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Affiliation(s)
- Pan Wang
- Department of Neurology, Institute of Geriatrics and Gerontology, Chinese PLA General Hospital, Beijing, 100853, China.,Department of Neurology, Tianjin Huanhu Hospital, Tianjin, 300060, China
| | - Bo Zhou
- Department of Neurology, Institute of Geriatrics and Gerontology, Chinese PLA General Hospital, Beijing, 100853, China
| | - Hongxiang Yao
- Department of Radiology, Chinese PLA General Hospital, Beijing, 100853, China
| | - Yafeng Zhan
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.,School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Zengqiang Zhang
- Department of Neurology, Institute of Geriatrics and Gerontology, Chinese PLA General Hospital, Beijing, 100853, China.,Hainan Branch of Chinese PLA General Hospital, Sanya, 572014, China
| | - Yue Cui
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
| | - Kaibin Xu
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jianhua Ma
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Luning Wang
- Department of Neurology, Institute of Geriatrics and Gerontology, Chinese PLA General Hospital, Beijing, 100853, China
| | - Ningyu An
- Department of Radiology, Chinese PLA General Hospital, Beijing, 100853, China
| | - Xi Zhang
- Department of Neurology, Institute of Geriatrics and Gerontology, Chinese PLA General Hospital, Beijing, 100853, China
| | - Yong Liu
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
| | - Tianzi Jiang
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.,CAS Center for Excellence in Brain Science, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
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37
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Garrett A, Gupta S, Reiss AL, Waring J, Sudheimer K, Anker L, Sosa N, Hallmayer JF, O'Hara R. Impact of 5-HTTLPR on hippocampal subregional activation in older adults. Transl Psychiatry 2015; 5:e639. [PMID: 26393485 PMCID: PMC5068801 DOI: 10.1038/tp.2015.131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/23/2015] [Indexed: 11/29/2022] Open
Abstract
Studies have shown that a functional polymorphism of the serotonin transporter gene (5-HTTLPR) impacts performance on memory-related tasks and the hippocampal structures that subserve these tasks. The short (s) allele of 5-HTTLPR has been linked to greater susceptibility for impaired memory and smaller hippocampal volume compared to the long allele (l). However, previous studies have not examined the associations between 5-HTTLPR allele and activation in subregions of the hippocampus. In this study, we used functional magnetic resonance imaging (fMRI) to measure activation in hippocampal and temporal lobe subregions in 36 elderly non-clinical participants performing a face-name encoding and recognition task. Although there were no significant differences in task performance between s allele carriers and l homozygotes, right CA1 and right parahippocampal activation during recognition errors was significantly greater in individuals bearing the s allele. In an exploratory analysis, we determined that these effects were more pronounced in s allele carriers with the apolipoprotein ɛ4 allele. Our results suggest that older individuals with the s allele inefficiently allocate neural resources while making errors in recognizing face-name associations, which could negatively impact memory performance during more challenging tasks.
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Affiliation(s)
- A Garrett
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Center for Interdisciplinary Brain Sciences Research, Stanford University School of Medicine, Stanford, CA, USA
| | - S Gupta
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - A L Reiss
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Center for Interdisciplinary Brain Sciences Research, Stanford University School of Medicine, Stanford, CA, USA
| | - J Waring
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Sierra Pacific Mental Illness, Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA
| | - K Sudheimer
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Sierra Pacific Mental Illness, Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA
| | - L Anker
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Sierra Pacific Mental Illness, Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA
| | - N Sosa
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - J F Hallmayer
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Sierra Pacific Mental Illness, Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA
| | - R O'Hara
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA,Sierra Pacific Mental Illness, Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305-5485, USA. E-mail:
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38
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Lee JH, Byun MS, Sohn BK, Choe YM, Yi D, Han JY, Choi HJ, Baek H, Woo JI, Lee DY. Functional Neuroanatomical Correlates of The Frontal Assessment Battery Performance in Alzheimer Disease: A FDG-PET Study. J Geriatr Psychiatry Neurol 2015; 28:184-92. [PMID: 25736510 DOI: 10.1177/0891988715573533] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 12/07/2014] [Indexed: 02/02/2023]
Abstract
BACKGROUND/OBJECTIVES We aimed to elucidate the functional neuroanatomical correlates of Frontal Assessment Battery (FAB) performances by applying [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to a large population of patients with Alzheimer disease (AD). METHODS The FAB was administered to 177 patients with AD, and regional cerebral glucose metabolism (rCMglc) was measured by FDG-PET scan. Correlations between FAB scores and rCMglc were explored using both region-of-interest-based (ROI-based) and voxel-based approaches. RESULTS The ROI-based analysis showed that FAB scores correlated with the rCMglc of the dorsolateral prefrontal cortices. Voxel-based approach revealed significant positive correlations between FAB scores and rCMglc which were in various cortical regions including the temporal and parietal cortices as well as frontal regions, independent of age, gender, and education. After controlling the effect of global disease severity with Mini-Mental State Examination score, significant positive correlation was found only in the bilateral prefrontal regions. CONCLUSIONS Although FAB scores are influenced by temporoparietal dysfunction due to the overall progression of AD, it likely reflects prefrontal dysfunction specifically regardless of global cognitive state or disease severity in patients with AD.
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Affiliation(s)
- Jun Ho Lee
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Min Soo Byun
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bo Kyung Sohn
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea Department of Psychiatry, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea
| | - Young Min Choe
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dahyun Yi
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ji Young Han
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hyo Jung Choi
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyewon Baek
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jong Inn Woo
- Institute of Human Behavioral Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Dong Young Lee
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
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Saura CA, Parra-Damas A, Enriquez-Barreto L. Gene expression parallels synaptic excitability and plasticity changes in Alzheimer's disease. Front Cell Neurosci 2015; 9:318. [PMID: 26379494 PMCID: PMC4548151 DOI: 10.3389/fncel.2015.00318] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/03/2015] [Indexed: 11/14/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by abnormal accumulation of β-amyloid and tau and synapse dysfunction in memory-related neural circuits. Pathological and functional changes in the medial temporal lobe, a region essential for explicit memory encoding, contribute to cognitive decline in AD. Surprisingly, functional imaging studies show increased activity of the hippocampus and associated cortical regions during memory tasks in presymptomatic and early AD stages, whereas brain activity declines as the disease progresses. These findings suggest an emerging scenario where early pathogenic events might increase neuronal excitability leading to enhanced brain activity before clinical manifestations of the disease, a stage that is followed by decreased brain activity as neurodegeneration progresses. The mechanisms linking pathology with synaptic excitability and plasticity changes leading to memory loss in AD remain largely unclear. Recent studies suggest that increased brain activity parallels enhanced expression of genes involved in synaptic transmission and plasticity in preclinical stages, whereas expression of synaptic and activity-dependent genes are reduced by the onset of pathological and cognitive symptoms. Here, we review recent evidences indicating a relationship between transcriptional deregulation of synaptic genes and neuronal activity and memory loss in AD and mouse models. These findings provide the basis for potential clinical applications of memory-related transcriptional programs and their regulatory mechanisms as novel biomarkers and therapeutic targets to restore brain function in AD and other cognitive disorders.
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Affiliation(s)
- Carlos A. Saura
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de BarcelonaBarcelona, Spain
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40
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Li HJ, Hou XH, Liu HH, Yue CL, He Y, Zuo XN. Toward systems neuroscience in mild cognitive impairment and Alzheimer's disease: a meta-analysis of 75 fMRI studies. Hum Brain Mapp 2014; 36:1217-32. [PMID: 25411150 DOI: 10.1002/hbm.22689] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/03/2014] [Accepted: 11/03/2014] [Indexed: 11/11/2022] Open
Abstract
Most of the previous task functional magnetic resonance imaging (fMRI) studies found abnormalities in distributed brain regions in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and few studies investigated the brain network dysfunction from the system level. In this meta-analysis, we aimed to examine brain network dysfunction in MCI and AD. We systematically searched task-based fMRI studies in MCI and AD published between January 1990 and January 2014. Activation likelihood estimation meta-analyses were conducted to compare the significant group differences in brain activation, the significant voxels were overlaid onto seven referenced neuronal cortical networks derived from the resting-state fMRI data of 1,000 healthy participants. Thirty-nine task-based fMRI studies (697 MCI patients and 628 healthy controls) were included in MCI-related meta-analysis while 36 task-based fMRI studies (421 AD patients and 512 healthy controls) were included in AD-related meta-analysis. The meta-analytic results revealed that MCI and AD showed abnormal regional brain activation as well as large-scale brain networks. MCI patients showed hypoactivation in default, frontoparietal, and visual networks relative to healthy controls, whereas AD-related hypoactivation mainly located in visual, default, and ventral attention networks relative to healthy controls. Both MCI-related and AD-related hyperactivation fell in frontoparietal, ventral attention, default, and somatomotor networks relative to healthy controls. MCI and AD presented different pathological while shared similar compensatory large-scale networks in fulfilling the cognitive tasks. These system-level findings are helpful to link the fundamental declines of cognitive tasks to brain networks in MCI and AD.
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Affiliation(s)
- Hui-Jie Li
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, 100101, China
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41
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The influence of age and mild cognitive impairment on associative memory performance and underlying brain networks. Brain Imaging Behav 2014; 9:776-89. [DOI: 10.1007/s11682-014-9335-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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42
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Sultzer DL, Leskin LP, Melrose RJ, Harwood DG, Narvaez TA, Ando TK, Mandelkern MA. Neurobiology of delusions, memory, and insight in Alzheimer disease. Am J Geriatr Psychiatry 2014; 22:1346-55. [PMID: 24021220 PMCID: PMC4254898 DOI: 10.1016/j.jagp.2013.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 06/14/2013] [Accepted: 06/18/2013] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Delusional thoughts are common among patients with Alzheimer disease (AD) and may be conceptually linked to memory deficits (cannot recall accurate information, which leads to inaccurate beliefs) and poor insight (unable to appreciate the illogic of beliefs). This study's goals were to examine the clinical associations among delusions, memory deficits, and poor insight; explore neurobiologic correlates for these symptoms; and identify shared mechanisms. METHODS In a cross-sectional analysis, 88 outpatients with AD (mean Mini-Mental State Exam score: 19.3) were studied. Delusional thoughts were assessed with the Neuropsychiatric Inventory, level of inaccurate insight was assessed with the Neurobehavioral Rating Scale, and memory was assessed with the Mattis Dementia Rating Scale memory subscale. (18)F-fluorodeoxyglucose positron emission tomography was used to measure regional cortical metabolism. Relationships between clinical ratings and regional cortical metabolic activity (voxel-based) were assessed using SPM2. RESULTS Patients with delusions had lower Dementia Rating Scale memory subscale scores. Neurobehavioral Rating Scale inaccurate insight scores were no different in those with and without delusions. Cortical metabolic activity was lower in the right lateral frontal cortex, orbitofrontal cortex, and bilateral temporal cortex in patients with delusions. Low cortical metabolic activity in the right lateral, inferior, and medial temporal cortex was associated with poorer memory. This region partially overlapped the region of hypometabolism associated with delusions. In contrast, low cortical metabolic activity in bilateral medial frontal cortex was associated with poor insight. CONCLUSION Delusions in AD are associated with dysfunction in specific frontal and temporal cortical regions. Delusions are partially clinically and neurobiologically linked to memory deficits but not to poor insight.
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Affiliation(s)
- David L. Sultzer
- Brain, Behavior, and Aging Research Center, VA Greater Los Angeles Healthcare System,Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA
| | - Lorraine P. Leskin
- Brain, Behavior, and Aging Research Center, VA Greater Los Angeles Healthcare System
| | - Rebecca J. Melrose
- Brain, Behavior, and Aging Research Center, VA Greater Los Angeles Healthcare System,Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA
| | - Dylan G. Harwood
- Brain, Behavior, and Aging Research Center, VA Greater Los Angeles Healthcare System,Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA
| | - Theresa A. Narvaez
- Brain, Behavior, and Aging Research Center, VA Greater Los Angeles Healthcare System
| | - Timothy K. Ando
- Brain, Behavior, and Aging Research Center, VA Greater Los Angeles Healthcare System
| | - Mark A. Mandelkern
- Nuclear Medicine Service, VA Greater Los Angeles Healthcare System,Department of Physics, University of California, Irvine
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Bastin C, Bahri MA, Miévis F, Lemaire C, Collette F, Genon S, Simon J, Guillaume B, Diana RA, Yonelinas AP, Salmon E. Associative memory and its cerebral correlates in Alzheimer׳s disease: evidence for distinct deficits of relational and conjunctive memory. Neuropsychologia 2014; 63:99-106. [PMID: 25172390 DOI: 10.1016/j.neuropsychologia.2014.08.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 12/29/2022]
Abstract
This study investigated the impact of Alzheimer׳s disease (AD) on conjunctive and relational binding in episodic memory. Mild AD patients and controls had to remember item-color associations by imagining color either as a contextual association (relational memory) or as a feature of the item to be encoded (conjunctive memory). Patients׳ performance in each condition was correlated with cerebral metabolism measured by FDG-PET. The results showed that AD patients had an impaired capacity to remember item-color associations, with deficits in both relational and conjunctive memory. However, performance in the two kinds of associative memory varied independently across patients. Partial Least Square analyses revealed that poor conjunctive memory was related to hypometabolism in an anterior temporal-posterior fusiform brain network, whereas relational memory correlated with metabolism in regions of the default mode network. These findings support the hypothesis of distinct neural systems specialized in different types of associative memory and point to heterogeneous profiles of memory alteration in Alzheimer׳s disease as a function of damage to the respective neural networks.
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Affiliation(s)
- Christine Bastin
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium.
| | - Mohamed Ali Bahri
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium
| | - Frédéric Miévis
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium
| | - Christian Lemaire
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium
| | - Fabienne Collette
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium
| | - Sarah Genon
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium
| | - Jessica Simon
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium
| | | | - Rachel A Diana
- Department of Psychology, Virginia Tech, Blacksburg, VA 24061, USA
| | - Andrew P Yonelinas
- Department of Psychology, University of California Davis, Davis, CA 95616, USA
| | - Eric Salmon
- Cyclotron Research Center, University of Liège, Allée du 6 Août, B30, 4000 Liège, Belgium; Memory Clinic, CHU Liège, 4000 Liège, Belgium
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44
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Zhong Y, Huang L, Cai S, Zhang Y, von Deneen KM, Ren A, Ren J. Altered effective connectivity patterns of the default mode network in Alzheimer's disease: an fMRI study. Neurosci Lett 2014; 578:171-5. [PMID: 24996191 PMCID: PMC6293460 DOI: 10.1016/j.neulet.2014.06.043] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/21/2014] [Accepted: 06/23/2014] [Indexed: 11/28/2022]
Abstract
The aim of this work is to investigate the differences of effective connectivity of the default mode network (DMN) in Alzheimer's disease (AD) patients and normal controls (NC). The technique of independent component analysis (ICA) was applied to identify DMN components and multivariate Granger causality analysis (mGCA) was used to explore an effective connectivity pattern. We found that: (i) connections in AD were decreased than those in NC, in terms of intensity and quantity. Posterior cingulated cortex (PCC) exhibited significant activity in NC as it connected with most of the other regions within the DMN. Besides, the PCC was the convergence center which only received interactions from other regions; (ii) right inferior temporal cortex (rITC) in the NC exhibited stronger interactions with other regions within the DMN compared with AD patients; and (iii) interactions between medial prefrontal cortex (MPFC) and bilateral inferior parietal cortex (IPC) in the NC were weaker than those in AD patients. These findings may implicate a brain dysfunction in AD patients and reveal more pathophysiological characteristics of AD.
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Affiliation(s)
- Yufang Zhong
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China
| | - Liyu Huang
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China.
| | - Suping Cai
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China
| | - Yun Zhang
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China
| | - Karen M von Deneen
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China
| | - Aifeng Ren
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China
| | - Junchan Ren
- School of Life Science and Technology, Xidian University, Xi-an, Shaanxi 710071, China
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45
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Dhanjal NS, Wise RJS. Frontoparietal cognitive control of verbal memory recall in Alzheimer's disease. Ann Neurol 2014; 76:241-51. [PMID: 24933580 DOI: 10.1002/ana.24199] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 06/09/2014] [Accepted: 06/09/2014] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Episodic memory retrieval is reliant upon cognitive control systems, of which 2 have been identified with functional neuroimaging: a cingulo-opercular salience network (SN) and a frontoparietal executive network (EN). In Alzheimer's disease (AD), pathology is distributed throughout higher-order cortices. The hypotheses were that this frontoparietal pathology would impair activity associated with verbal memory recall; and that central cholinesterase inhibition (ChI) would modulate this, improving memory recall. METHODS Functional magnetic resonance imaging was used to study normal participants and 2 patient groups: mild cognitive impairment (MCI) and AD. Activity within the EN and SN was observed during free recall of previously heard sentences, and related to measures of recall accuracy. RESULTS In normal subjects, trials with reduced recall were associated with greater activity in both the SN and EN. Better recall was associated with greater activity in medial regions of the default mode network. By comparison, AD patients showed attenuated responses in both the SN and EN compared with either controls or MCI patients, even after recall performance was matched between groups. Following ChI, AD patients showed no modulation of activity within the SN, but increased activity within the EN. There was also enhanced activity within regions associated with episodic and semantic memory during less successful recall, requiring greater cognitive control. INTERPRETATION The results indicate that in AD, impaired responses of cognitive control networks during verbal memory recall are partly responsible for reduced recall performance. One action of symptom-modifying treatment is partially to reverse the abnormal function of frontoparietal cognitive control and temporal lobe memory networks.
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Affiliation(s)
- Novraj S Dhanjal
- Division of Brain Sciences and Medical Research Council Clinical Sciences Centre, Imperial College London, London, United Kingdom
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46
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Sadigh-Eteghad S, Majdi A, Farhoudi M, Talebi M, Mahmoudi J. Different patterns of brain activation in normal aging and Alzheimer's disease from cognitional sight: meta analysis using activation likelihood estimation. J Neurol Sci 2014; 343:159-66. [PMID: 24950901 DOI: 10.1016/j.jns.2014.05.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/26/2014] [Accepted: 05/29/2014] [Indexed: 10/25/2022]
Abstract
Alzheimer disease (AD) is a chronic neurological disease, frequently affecting cognitional functions. Recently, a large body of neuro-imaging studies have aimed at finding reliable biomarkers of AD for early diagnosis of disease in contrast with healthy elderlies. We intended to have a meta-analytical study on recent functional neuroimaging studies to find the relationship between cognition in AD patients and normal elderlies. A systematic search was conducted to collect functional neuroimaging studies such as positron emission therapy (PET) and functional magnetic resonance imaging (fMRI) in AD patients and healthy elderlies. The coordinates of regions related to cognition were meta-analyzed using the activation likelihood estimation (ALE) method and Sleuth software. P-value map at the false discovery rate (FDR) of P<0.05 thresholds and the clusters with a minimum size of 200 mm(3) were considered. Data were visualized with MANGO software. Forty-one articles that explored the areas activated during cognition in normal elderly subjects and AD patients were found. According to the findings, left middle frontal gyrus and left precuneus are the most activated areas in cognitional tasks in healthy elderlies and AD patients respectively. In normal elderly subjects and AD patients, comparison of ALE maps and reverse contrast showed that insula and left precuneus were the most activated areas in cognitional aspects respectively. With respect to unification of left precuneus activation in cognitional tasks, it seems that this point can be a hallmark in primary differentiation of AD and healthy individuals.
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Affiliation(s)
- Saeed Sadigh-Eteghad
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Majdi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Mehdi Farhoudi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahnaz Talebi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Javad Mahmoudi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
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47
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Liu Y, Yu C, Zhang X, Liu J, Duan Y, Alexander-Bloch AF, Liu B, Jiang T, Bullmore E. Impaired long distance functional connectivity and weighted network architecture in Alzheimer's disease. Cereb Cortex 2014; 24:1422-35. [PMID: 23314940 PMCID: PMC4215108 DOI: 10.1093/cercor/bhs410] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Alzheimer's disease (AD) is increasingly recognized as a disconnection syndrome, which leads to cognitive impairment due to the disruption of functional activity across large networks or systems of interconnected brain regions. We explored abnormal functional magnetic resonance imaging (fMRI) resting-state dynamics, functional connectivity, and weighted functional networks, in a sample of patients with severe AD (N = 18) and age-matched healthy volunteers (N = 21). We found that patients had reduced amplitude and regional homogeneity of low-frequency fMRI oscillations, and reduced the strength of functional connectivity, in several regions previously described as components of the default mode network, for example, medial posterior parietal cortex and dorsal medial prefrontal cortex. In patients with severe AD, functional connectivity was particularly attenuated between regions that were separated by a greater physical distance; and loss of long distance connectivity was associated with less efficient global and nodal network topology. This profile of functional abnormality in severe AD was consistent with the results of a comparable analysis of data on 2 additional groups of patients with mild AD (N = 17) and amnestic mild cognitive impairment (MCI; N = 18). A greater degree of cognitive impairment, measured by the mini-mental state examination across all patient groups, was correlated with greater attenuation of functional connectivity, particularly over long connection distances, for example, between anterior and posterior components of the default mode network, and greater reduction of global and nodal network efficiency. These results indicate that neurodegenerative disruption of fMRI oscillations and connectivity in AD affects long-distance connections to hub nodes, with the consequent loss of network efficiency. This profile was evident also to a lesser degree in the patients with less severe cognitive impairment, indicating that the potential of resting-state fMRI measures as biomarkers or predictors of disease progression in AD.
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Affiliation(s)
- Yong Liu
- LIAMA Center for Computational Medicine, National Laboratory of Pattern Recognition, Institute of Automation, The Chinese Academy of Sciences, Beijing 100190, China,Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Cambridge CB2 3EB, UK
| | - Chunshui Yu
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin 300052, China
| | | | | | - Yunyun Duan
- Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing 100053, China
| | | | - Bing Liu
- LIAMA Center for Computational Medicine, National Laboratory of Pattern Recognition, Institute of Automation, The Chinese Academy of Sciences, Beijing 100190, China
| | - Tianzi Jiang
- LIAMA Center for Computational Medicine, National Laboratory of Pattern Recognition, Institute of Automation, The Chinese Academy of Sciences, Beijing 100190, China,Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China,The Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Australia and
| | - Ed Bullmore
- Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Cambridge CB2 3EB, UK,Clinical Unit Cambridge, GlaxoSmithKline, Addenbrooke's Hospital, Cambridge CB2 0SZ, UK
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48
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McLaren DG, Sperling RA, Atri A. Flexible modulation of network connectivity related to cognition in Alzheimer's disease. Neuroimage 2014; 100:544-57. [PMID: 24852459 DOI: 10.1016/j.neuroimage.2014.05.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/06/2014] [Accepted: 05/07/2014] [Indexed: 11/26/2022] Open
Abstract
Functional neuroimaging tools, such as fMRI methods, may elucidate the neural correlates of clinical, behavioral, and cognitive performance. Most functional imaging studies focus on regional task-related activity or resting state connectivity rather than how changes in functional connectivity across conditions and tasks are related to cognitive and behavioral performance. To investigate the promise of characterizing context-dependent connectivity-behavior relationships, this study applies the method of generalized psychophysiological interactions (gPPI) to assess the patterns of associative-memory-related fMRI hippocampal functional connectivity in Alzheimer's disease (AD) associated with performance on memory and other cognitively demanding neuropsychological tests and clinical measures. Twenty-four subjects with mild AD dementia (ages 54-82, nine females) participated in a face-name paired-associate encoding memory study. Generalized PPI analysis was used to estimate the connectivity between the hippocampus and the whole brain during encoding. The difference in hippocampal-whole brain connectivity between encoding novel and encoding repeated face-name pairs was used in multiple-regression analyses as an independent predictor for 10 behavioral, neuropsychological and clinical tests. The analysis revealed connectivity-behavior relationships that were distributed, dynamically overlapping, and task-specific within and across intrinsic networks; hippocampal-whole brain connectivity-behavior relationships were not isolated to single networks, but spanned multiple brain networks. Importantly, these spatially distributed performance patterns were unique for each measure. In general, out-of-network behavioral associations with encoding novel greater than repeated face-name pairs hippocampal-connectivity were observed in the default-mode network, while correlations with encoding repeated greater than novel face-name pairs hippocampal-connectivity were observed in the executive control network (p<0.05, cluster corrected). Psychophysiological interactions revealed significantly more extensive and robust associations between paired-associate encoding task-dependent hippocampal-whole brain connectivity and performance on memory and behavioral/clinical measures than previously revealed by standard activity-behavior analysis. Compared to resting state and task-activation methods, gPPI analyses may be more sensitive to reveal additional complementary information regarding subtle within- and between-network relations. The patterns of robust correlations between hippocampal-whole brain connectivity and behavioral measures identified here suggest that there are 'coordinated states' in the brain; that the dynamic range of these states is related to behavior and cognition; and that these states can be observed and quantified, even in individuals with mild AD.
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Affiliation(s)
- Donald G McLaren
- Department of Neurology, Massachusetts General Hospital, 15 Parkman Street, WACC 715, Boston, MA 02114, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, MA 02129, USA; Geriatric Research, Education and Clinical Center, ENRM VA Medical Center, 200 Springs Road, Bedford, MA 01730, USA; Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
| | - Reisa A Sperling
- Department of Neurology, Massachusetts General Hospital, 15 Parkman Street, WACC 715, Boston, MA 02114, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, MA 02129, USA; Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Center for Alzheimer Research and Treatment, Department of Neurology, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA.
| | - Alireza Atri
- Department of Neurology, Massachusetts General Hospital, 15 Parkman Street, WACC 715, Boston, MA 02114, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, MA 02129, USA; Geriatric Research, Education and Clinical Center, ENRM VA Medical Center, 200 Springs Road, Bedford, MA 01730, USA; Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
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49
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Nellessen N, Rottschy C, Eickhoff SB, Ketteler ST, Kuhn H, Shah NJ, Schulz JB, Reske M, Reetz K. Specific and disease stage-dependent episodic memory-related brain activation patterns in Alzheimer's disease: a coordinate-based meta-analysis. Brain Struct Funct 2014; 220:1555-71. [PMID: 24633738 DOI: 10.1007/s00429-014-0744-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 02/28/2014] [Indexed: 12/31/2022]
Abstract
Episodic memory is typically affected during the course of Alzheimer's disease (AD). Due to the pronounced heterogeneity of functional neuroimaging studies on episodic memory impairments in mild cognitive impairment (MCI) and AD regarding their methodology and findings, we aimed to delineate consistent episodic memory-related brain activation patterns. We performed a systematic, quantitative, coordinate-based whole-brain activation likelihood estimation meta-analysis of 28 functional magnetic resonance imaging (fMRI) studies comprising 292 MCI and 102 AD patients contrasted to 409 age-matched control subjects. We included episodic encoding and/or retrieval phases, investigated the effects of group, verbal or image stimuli and correlated mean Mini-Mental-Status-Examination (MMSE) scores with the modelled activation estimates. MCI patients presented increased right hippocampal activation during memory encoding, decreased activation in the left hippocampus and fusiform gyrus during retrieval tasks, as well as attenuated activation in the right anterior insula/inferior frontal gyrus during verbal retrieval. In AD patients, however, stronger activation within the precuneus during encoding tasks was accompanied by attenuated right hippocampal activation during retrieval tasks. Low cognitive performance (MMSE scores) was associated with stronger activation of the precuneus and reduced activation of the right (para)hippocampus and anterior insula/inferior frontal gyrus. This meta-analysis provides evidence for a specific and probably disease stage-dependent brain activation pattern related to the pathognomonic AD characteristic of episodic memory loss.
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Affiliation(s)
- Nils Nellessen
- Department of Neurology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
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50
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Cha J, Jo HJ, Kim HJ, Seo SW, Kim HS, Yoon U, Park H, Na DL, Lee JM. Functional alteration patterns of default mode networks: comparisons of normal aging, amnestic mild cognitive impairment and Alzheimer's disease. Eur J Neurosci 2013; 37:1916-24. [PMID: 23773060 DOI: 10.1111/ejn.12177] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/21/2013] [Accepted: 01/30/2013] [Indexed: 11/27/2022]
Abstract
Most default mode network (DMN) studies in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) are based on the comparison of only two groups, namely patients and controls. Information derived from comparing three groups, normal, aMCI and AD, simultaneously may lead us to better understand the progression of dementia. The purpose of this study was to evaluate functional connectivity of DMN in the continuum from normal through aMCI to AD. Differences in functional connectivity were compared between the three groups using independent component analysis. The relationship between functional connectivity and disease progression was investigated using multiple regression analysis with Mini-Mental State Examination (MMSE) scores. The results revealed differences throughout the left posterior cingulate cortex (PCC), left middle temporal gyrus (MTG), right middle frontal gyrus (MFG) and bilateral parahippocampal gyrus (PHG). Both patients with aMCI and those with AD showed decreased connectivity in the left PCC and left PHG compared with healthy subjects. Furthermore, patients with AD also showed decreased connectivity in the left MTG and right PHG. Increased functional connectivity was observed in the right MFG of patients with AD compared with other groups. MMSE scores exhibited significant positive and negative correlations with functional connectivity in PCC, MTG and MFG regions. Taken together, increased functional connectivity in the MFG for AD patients might compensate for the loss of function in the PCC and MTG via compensatory mechanisms in corticocortical connections.
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Affiliation(s)
- Jungho Cha
- Department of Biomedical Engineering, Hanyang University, Seoul, South Korea
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