scholarly journals Abnormal dynamic functional connectivity in Alzheimer’s disease

2020 ◽  
Vol 26 (9) ◽  
pp. 962-971 ◽  
Author(s):  
Yue Gu ◽  
Ying Lin ◽  
Liangliang Huang ◽  
Junji Ma ◽  
Jinbo Zhang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Dynamic Functional Connectivity

scholarly journals Cognitive Improvement is Correlated with Increased Dynamic Functional Connectivity of Default Mode Network by Personalized rTMS in Alzheimer's Disease

2021 ◽  
Author(s):  
Lili Wei ◽  
Jintao Wang ◽  
Yingchun Zhang ◽  
Luoyi Xu ◽  
Kehua Yang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Present Report ◽  
Verbal Learning ◽  
Dynamic Functional Connectivity ◽  
Default Mode ◽  
Cognitive Improvement ◽  
Promising Therapeutic Approach

Abstract Background Repetitive transcranial magnetic stimulation (rTMS) is thought to be a promising therapeutic approach for Alzheimer's disease patients. Methods In the present report, a double-blind, randomized, sham-controlled rTMS trial was conducted in mild-to-moderate Alzheimer's disease patients. High-frequency rTMS was delivered to a subject-specific left lateral parietal region that demonstrated highest functional connectivity with the hippocampus using resting-state fMRI. The Mini Mental State Examination (MMSE) and Philadelphia Verbal Learning Test (PVLT) were used to evaluate patients’ cognitive functions. Results Patients receiving active rTMS treatment (n = 31) showed a significant increase in the MMSE, PVLT-Immediate recall, and PVLT-Short Delay recall scores after two weeks of rTMS treatment, whereas patients who received sham rTMS (n = 27) did not show significant changes in these measures. Dynamic functional connectivity (dFC) magnitude of the default mode network (DMN) in the active-rTMS group showed a significant increase after two weeks of rTMS treatment, and no significant changes were found in the sham-rTMS group. There was a significantly positive correlation between changes of the MMSE and changes of the dFC magnitude of DMN in the active-rTMS group, but not the sham-rTMS group. Conclusions Our findings are novel in demonstrating the feasibility and effectiveness of the fMRI-guided rTMS treatment in Alzheimer's disease patients, and DMN might play a vital role in therapeutic effectiveness of rTMS in Alzheimer’s disease. Trial registration: China National Medical Research Platform (http://114.255.48.20/login, No:MR-33-20-004217), retrospectively registered 2020-12-23.

Hippocampus-Based Dynamic Functional Connectivity Mapping in the Early Stages of Alzheimer’s Disease

2021 ◽  
pp. 1-12
Author(s):  
Jianlin Wang ◽  
Pan Wang ◽  
Yuan Jiang ◽  
Zedong Wang ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Functional Connectivity ◽  
Anterior Lobe ◽  
Dynamic Functional Connectivity ◽  
Seed Point ◽  
Left And Right ◽  
The Common

Background: The hippocampus with varying degrees of atrophy was a crucial neuroimaging feature resulting in the declining memory and cognitive function in Alzheimer’s disease (AD). However, the abnormal dynamic functional connectivity (DFC) in both white matter (WM) and gray matter (GM) from the left and right hippocampus remains unclear. Objective: To explore the abnormal DFC within WM and GM from the left and right hippocampus across the different stages of AD. Methods: Current study employed the OASIS-3 dataset including 43 mild cognitive impairment (MCI), 71 pre-mild cognitive impairment (pre-MCI), and matched 87 normal cognitive (NC). Adopting the FMRIB’s Integrated Registration and Segmentation Tool, we obtained the left and right hippocampus mask. Based on above hippocampus mask as seed point, we calculated the DFC between left/right hippocampus and all voxel time series within whole brain. One-way ANOVA analysis was performed to estimate the abnormal DFC among MCI, pre-MCI, and NC groups. Results: We found that MCI and pre-MCI groups showed the common abnormalities of DFC in the Temporal_Mid_L, Cingulum_Mid_L, and Thalamus_L. Specific abnormalities were found in the Cerebelum_9_L and Precuneus of MCI group and Vermis_8 and Caudate_L of pre-MCI group. In addition, we found that DFC within WM regions also showed the common low DFC for the Cerebellum anterior lobe-WM, Corpus callosum, and Frontal lobe-WM in MCI and pre-MCI group. Conclusion: Our findings provided a novel information for discover the pathophysiological mechanisms of AD and indicate WM lesions were also an important cause of cognitive decline in AD.

scholarly journals Parietal-Hippocampal rTMS Improves Cognitive Function in Alzheimer's Disease by Inducing Increased Dynamic Functional Connectivity of Default Mode Network

2021 ◽  
Author(s):  
Lili Wei ◽  
Yingchun Zhang ◽  
Jintao Wang ◽  
Luoyi Xu ◽  
Kehua Yang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Function ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Verbal Learning ◽  
Post Treatment ◽  
Dynamic Functional Connectivity ◽  
Default Mode

Abstract Background Alzheimer’s disease, a neurodegenerative disease with significant social and economic impact, is mainly treated by focusing on decelerating cognition decline. Parietal-hippocampal repetitive transcranial magnetic stimulation (rTMS) improves memory and cognitive function in Alzheimer’s disease, however, the underlying therapeutic mechanism has not been elucidated. Methods A double-blind, randomized, sham-controlled parietal-hippocampal rTMS trial of mild-to-moderate Alzheimer's disease patients was conducted in the current study. High-frequency rTMS was applied to a subject-specific left lateral parietal region with the highest functional connectivity with the hippocampus based on resting-state fMRI. Patients were randomized to either rTMS or sham treatment (five sessions/week for a total of 10 sessions). A multimodal MRI scan and a complete neuropsychological battery of tests were conducted at baseline, immediately after the intervention and 12-week follow-up after the rTMS treatment. Primary outcomes were differences in the Mini Mental State Examination (MMSE) and Philadelphia Verbal Learning Test (PVLT) scores between the groups and between pre- and post-treatment. Moreover, flexible least squares (FLS) method was used to calculate the dynamic functional connectivity (dFC) of the default mode network (DMN), and dFC changes were compared between the groups and between pre- and post-treatment. Results Patients undergoing active rTMS treatment (n = 31) for two weeks showed higher MMSE, PVLT-Immediate recall, and PVLT-Short Delay recall scores, whereas those who underwent sham rTMS (n = 27) treatment did not show significant changes in these measures. Dynamic functional connectivity (dFC) magnitude of the default mode network (DMN) was significantly higher after two weeks of rTMS treatment in the patients who underwent active-rTMS treatment, however, no significant changes were observed in patients who received sham-rTMS treatment. dFC magnitude reduced to baseline level at 12-week follow-up, which resembled the trajectory of the cognitive measures. A significant positive correlation was observed between changes in MMSE and changes in the dFC magnitude of DMN in patients who underwent active-rTMS treatment, but not in those who received sham-rTMS treatment. Conclusions The findings of the current study indicate that fMRI-guided rTMS treatment improves memory and cognitive function of Alzheimer's disease patients. In addition, the findings indicate that the DMN functional connectivity contributes to therapeutic effectiveness of rTMS. Trial registration: China National Medical Research Platform (http://114.255.48.20/login, No:MR-33-20-004217), retrospectively registered 2020-12-23.

scholarly journals Dynamic functional connectivity changes in dementia with Lewy bodies and Alzheimer's disease

2019 ◽  
Vol 22 ◽  
pp. 101812 ◽  
Author(s):  
Julia Schumacher ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
Alan J. Thomas ◽  
Marcus Kaiser ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Dynamic Functional Connectivity

scholarly journals Exploring dynamic functional connectivity alterations in the preclinical stage of Alzheimer’s disease: an exploratory study from SICOLDE

2021 ◽  
Author(s):  
Fan Yang ◽  
Xueyan Jiang ◽  
Feng Yue ◽  
Luyao Wang ◽  
Boecker Henning ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Cognitive Decline ◽  
Standardized Uptake Value ◽  
Magnetic Resonance Images ◽  
Subjective Cognitive Decline ◽  
Dynamic Functional Connectivity ◽  
Preclinical Stage ◽  
Neuropsychological Assessments

Abstract IntroductionExploring functional connectivity (FC) alterations is important for the understanding of underlying neuronal network alterations in subjective cognitive decline (SCD). The objective of this study was to discover stable and subtle dynamic functional connectivity (FC) changes in the preclinical stage of Alzheimer’s disease (AD), and to explore the associations between dynamic FCs and amyloid accumulation.MethodsNinety-seven normal control (NC) subjects, 101 subjective cognitive decline (SCD) subjects, and 55 cognitive impairment (CI) subjects with neuropsychological assessments and resting-state functional magnetic resonance images constituted the whole cohort. Of these, 29 NCs and 52 SCDs with amyloid images were selected as the sub-cohort. First, independent components (ICs) identified by group independent component analysis (ICA) were used to define static and dynamic brain networks. Static and sliding-window dynamic FCs were then calculated. Second, the connection between each pair of ICs was compared between groups in the two cohorts. Hubs were obtained and considered as seeds in the subsequent seed-based dynamic FC analysis. One-way analysis of variance (ANOVA) was used to compare the seed-based dynamic FC maps between groups in the whole cohort, while a 2×2 ANOVA model was used to measure the group or amyloid effects in the sub-cohort. Post-hoc analysis was applied, and differences were considered significant if the cluster-level FWE-corrected p-value was less than 0.001. Finally, correlation analysis was conducted between the altered dynamic FCs, neuropsychological assessments, and amyloid burden.ResultsThe results showed that 42 ICs were revealed. Compared with the static FCs, the dynamic FCs were found to be more stable and sensitive between groups. The effective dynamic FCs included those between the salience/ventral attention network, the default mode network, and the visual network. Specifically, the dynamic FC of the thalamus/caudate (IC 25) drove the hub role in the group differences between the NC and SCD groups. In the seed-based dynamic FC analysis, the dynamic FC between the thalamus/caudate and the middle temporal/frontal gyrus was observed to be higher in the SCD and CI groups in the whole cohort. Moreover, a higher dynamic FC between the thalamus/caudate and visual cortex was observed in the amyloid positive group. Finally, the altered dynamic FC was associated with the amyloid global level standardized uptake value ratio.ConclusionOur findings indicate that dynamic FCs can reflect subtle changes in the preclinical stage of AD.

scholarly journals Dynamic Functional Connectivity Changes in Dementia with Lewy Bodies and Alzheimer's Disease

2018 ◽  
Author(s):  
Julia Schumacher ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
Alan J. Thomas ◽  
Marcus Kaiser ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Dynamic Functional Connectivity
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