scholarly journals P4-142: GLUCOSE METABOLISM IMPACT ON FUNCTIONAL CONNECTIVITY IN ALZHEIMER'S DISEASE

2014 ◽  
Vol 10 ◽  
pp. P840-P841
Author(s):  
Seqian Wang ◽  
Sulantha Sanjeewa Mathotaarachchi ◽  
Maxime Parent ◽  
Sara Mohades ◽  
Antoine Leuzy ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Glucose Metabolism

scholarly journals IC-P-140: GLUCOSE METABOLISM IMPACT ON FUNCTIONAL CONNECTIVITY IN ALZHEIMER'S DISEASE

2014 ◽  
Vol 10 ◽  
pp. P80-P80
Author(s):  
Seqian Wang ◽  
Felix Carbonell ◽  
Thomas Beaudry ◽  
Sulantha Sanjeewa Mathotaarachchi ◽  
Antoine Leuzy ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Glucose Metabolism

scholarly journals Simultaneous PET/fMRI Detects Distinctive Alterations in Functional Connectivity and Glucose Metabolism of Precuneus Subregions in Alzheimer’s Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Miao Zhang ◽  
Wanqing Sun ◽  
Ziyun Guan ◽  
Jialin Hu ◽  
Binyin Li ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Glucose Metabolism ◽  
Clustering Algorithm ◽  
Brain Network ◽  
Resting State Functional Connectivity ◽  
Metabolic Pattern ◽  
Cognitively Normal ◽  
Functional Connectivity Strength

As a central hub in the interconnected brain network, the precuneus has been reported showing disrupted functional connectivity and hypometabolism in Alzheimer’s disease (AD). However, as a highly heterogeneous cortical structure, little is known whether individual subregion of the precuneus is uniformly or differentially involved in the progression of AD. To this end, using a hybrid PET/fMRI technique, we compared resting-state functional connectivity strength (FCS) and glucose metabolism in dorsal anterior (DA_pcu), dorsal posterior (DP_pcu) and ventral (V_pcu) subregions of the precuneus among 20 AD patients, 23 mild cognitive impairment (MCI) patients, and 27 matched cognitively normal (CN) subjects. The sub-parcellation of precuneus was performed using a K-means clustering algorithm based on its intra-regional functional connectivity. For the whole precuneus, decreased FCS (p = 0.047) and glucose hypometabolism (p = 0.006) were observed in AD patients compared to CN subjects. For the subregions of the precuneus, decreased FCS was found in DP_pcu of AD patients compared to MCI patients (p = 0.011) and in V_pcu for both MCI (p = 0.006) and AD (p = 0.008) patients compared to CN subjects. Reduced glucose metabolism was found in DP_pcu of AD patients compared to CN subjects (p = 0.038) and in V_pcu of AD patients compared to both MCI patients (p = 0.045) and CN subjects (p < 0.001). For both FCS and glucose metabolism, DA_pcu remained relatively unaffected by AD. Moreover, only in V_pcu, disruptions in FCS (r = 0.498, p = 0.042) and hypometabolism (r = 0.566, p = 0.018) were significantly correlated with the cognitive decline of AD patients. Our results demonstrated a distinctively disrupted functional and metabolic pattern from ventral to dorsal precuneus affected by AD, with V_pcu and DA_pcu being the most vulnerable and conservative subregion, respectively. Findings of this study extend our knowledge on the differential roles of precuneus subregions in AD.

scholarly journals Decoupling of regional neural activity and inter-regional functional connectivity in Alzheimer’s Disease – a simultaneous PET/MRI study

2021 ◽  
Author(s):  
Somayeh Maleki Balajoo ◽  
Farzaneh Rahmani ◽  
Reza Khosrowabadi ◽  
Chun Meng ◽  
Simon B. Eickhoff ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Glucose Metabolism ◽  
Neural Activity ◽  
Fdg Pet ◽  
Disease Status ◽  
Blood Oxygenation ◽  
Clustering Coefficient ◽  
Regional Metabolism

Abstract Purpose: Alzheimer’s disease (AD) and mild cognitive impairment (MCI), a syndrome at-risk for AD, are characterized by both aberrant regional neural activity and disrupted inter-regional functional connectivity (FC). It is, however, not clear how aberrant regional neural activity and inter-regional FC interact across MCI and AD. Thus, we investigated the interplay between regional neural activity and inter-regional topological measures of FC in MCI and AD using simultaneous PET/MR measurement.Methods: We scanned 19 patients with MCI, 33 patients with AD, and 26 healthy individuals by simultaneous FDG-PET/resting-state fMRI. First, we assessed regional glucose metabolism identified through FDG-PET (as a proxy of regional neural activity), and inter-regional FC topology through clustering coefficient and degree centrality (as surrogates of local segregation and global connectivity, respectively, based on fMRI blood oxygenation). Next, we examined the potential moderating effect of disease status (MCI or AD) on the link between regional metabolism and inter-regional FC topology using hierarchical moderated multiple regression analysis.Results: Not only regional metabolism and inter-regional FC metrics were disrupted in in MCI and AD patients, but also AD significantly alters coupling between regional metabolism and inter-regional FC, particularly in the right inferior temporal, supplementary motor area and planum temporal areas, where AD moderated the effect of their regional glucose metabolism on predicting their inter-reginal FC. Conclusion: Our findings demonstrated that AD decouples the association between regional neural activity and functional segregation.

Altered Functional Connectivity of the Marginal Division in Alzheimer’s Disease

2014 ◽  
Vol 11 (2) ◽  
pp. 145-155 ◽  
Author(s):  
Zengqiang Zhang ◽  
Yong Liu ◽  
Bo Zhou ◽  
Jinlong Zheng ◽  
Hongxiang Yao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Marginal Division

scholarly journals Topographic patterns of white matter hyperintensities are associated with multimodal neuroimaging biomarkers of Alzheimer’s disease

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Malo Gaubert ◽  
Catharina Lange ◽  
Antoine Garnier-Crussard ◽  
Theresa Köbe ◽  
Salma Bougacha ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
White Matter ◽  
Glucose Metabolism ◽  
Corpus Callosum ◽  
Gray Matter ◽  
Fdg Pet ◽  
White Matter Hyperintensities ◽  
Gray Matter Volume ◽  
Matter Volume

Abstract Background White matter hyperintensities (WMH) are frequently found in Alzheimer’s disease (AD). Commonly considered as a marker of cerebrovascular disease, regional WMH may be related to pathological hallmarks of AD, including beta-amyloid (Aβ) plaques and neurodegeneration. The aim of this study was to examine the regional distribution of WMH associated with Aβ burden, glucose hypometabolism, and gray matter volume reduction. Methods In a total of 155 participants (IMAP+ cohort) across the cognitive continuum from normal cognition to AD dementia, FLAIR MRI, AV45-PET, FDG-PET, and T1 MRI were acquired. WMH were automatically segmented from FLAIR images. Mean levels of neocortical Aβ deposition (AV45-PET), temporo-parietal glucose metabolism (FDG-PET), and medial-temporal gray matter volume (GMV) were extracted from processed images using established AD meta-signature templates. Associations between AD brain biomarkers and WMH, as assessed in region-of-interest and voxel-wise, were examined, adjusting for age, sex, education, and systolic blood pressure. Results There were no significant associations between global Aβ burden and region-specific WMH. Voxel-wise WMH in the splenium of the corpus callosum correlated with greater Aβ deposition at a more liberal threshold. Region- and voxel-based WMH in the posterior corpus callosum, along with parietal, occipital, and frontal areas, were associated with lower temporo-parietal glucose metabolism. Similarly, lower medial-temporal GMV correlated with WMH in the posterior corpus callosum in addition to parietal, occipital, and fontal areas. Conclusions This study demonstrates that local white matter damage is correlated with multimodal brain biomarkers of AD. Our results highlight modality-specific topographic patterns of WMH, which converged in the posterior white matter. Overall, these cross-sectional findings corroborate associations of regional WMH with AD-typical Aß deposition and neurodegeneration.

scholarly journals Functional connectivity of the nucleus basalis of Meynert in Lewy body dementia and Alzheimer’s disease

2021 ◽  
pp. 1-6
Author(s):  
Julia Schumacher ◽  
Alan J. Thomas ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
John T. O’Brien ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Lewy Body ◽  
Cholinergic System ◽  
Structural Changes ◽  
Lewy Body Dementia ◽  
Occipital Cortex ◽  
Nucleus Basalis ◽  
Nucleus Basalis Of Meynert

ABSTRACT Cholinergic deficits are a hallmark of Alzheimer’s disease (AD) and Lewy body dementia (LBD). The nucleus basalis of Meynert (NBM) provides the major source of cortical cholinergic input; studying its functional connectivity might, therefore, provide a tool for probing the cholinergic system and its degeneration in neurodegenerative diseases. Forty-six LBD patients, 29 AD patients, and 31 healthy age-matched controls underwent resting-state functional magnetic resonance imaging (fMRI). A seed-based analysis was applied with seeds in the left and right NBM to assess functional connectivity between the NBM and the rest of the brain. We found a shift from anticorrelation in controls to positive correlations in LBD between the right/left NBM and clusters in right/left occipital cortex. Our results indicate that there is an imbalance in functional connectivity between the NBM and primary visual areas in LBD, which provides new insights into alterations within a part of the corticopetal cholinergic system that go beyond structural changes.

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