scholarly journals Medial temporal lobe (MTL) ‐ default‐mode network (DMN) functional connectivity disruption in the progression of Alzheimer’s disease

2020 ◽  
Vol 16 (S4) ◽  
Author(s):  
Kamil A Grajski ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Temporal Lobe ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Default Mode

scholarly journals Differential medial temporal lobe and default-mode network functional connectivity and morphometric changes in Alzheimer’s Disease

2017 ◽  
Author(s):  
Kamil A. Grajski ◽  
Steven L. Bressler ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Functional Connectivity ◽  
Temporal Lobe ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Resting State Functional Connectivity ◽  
Default Mode

AbstractWe report group level differential detection of medial temporal lobe resting-state functional connectivity disruption and morphometric changes in the transition from cognitively normal to early mild cognitive impairment in an age-, education- and gender-matched 105 subjects Alzheimer’s Disease Neuroimaging Initiative dataset. In mild Alzheimer’s Disease, but not early mild cognitive impairment, characteristic brain atrophy was detected in FreeSurfer estimates of cortical thickness and subcortical and hippocampal subfield volumes. By contrast, functional connectivity analysis detected earlier significant changes. In early mild cognitive impairment these changes involved medial temporal lobe regions of transentorhinal, perirhinal and entorhinal cortices (associated with the earliest stages of neurofibrillary changes in Alzheimer’s Disease), hippocampus, parahippocampal gyrus and temporal pole, and cortical regions comprising or co-activated with the default-mode network, including rostral and medial prefrontal cortex, anterior cingulate cortex, precuneus and inferior temporal cortex. Key findings include: a) focal and bilaterally symmetric spatial organization of affected medial temporal lobe regions; b) mutual hyperconnectivity bilaterally involving ventral medial temporal lobe structures (temporal pole, uncus); and c) dorsal medial temporal lobe hypoconnectivity with anterior and posterior midline default-mode network nodes. These findings position medial temporal lobe resting state functional connectivity as a candidate biomarker of an Alzheimer’s Disease pathophysiological cascade, potentially in advance of clinical biomarkers, and coincident with biomarkers of the earliest stages of Alzheimer’s neuropathology. Our results indicate that medial temporal lobe resting-state functional connectivity should be further investigated as a potential biomarker in the diagnosis of Alzheimer’s Disease.HighlightsFunctional connectivity change seen before structural change in Alzheimer’s DiseaseMedial temporal lobes mutually hyper-connect in mild cognitive impairmentMedial temporal lobe and default mode network decouple in mild cognitive impairmentLoci of functional change in hippocampi are focal with bilaterally symmetric featuresNonmonotonic functional connectivity changes in Alzheimer’s Disease progression

scholarly journals Race modifies default mode network connectivity in Alzheimer’s disease

2018 ◽  
Author(s):  
Maria B. Misiura ◽  
Junjie Wu ◽  
Deqiang Qiu ◽  
Jennifer C. Howell ◽  
Monica W. Parker ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
African Americans ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Memory Function ◽  
Default Mode ◽  
Neuropsychological Profile ◽  
Older African Americans

AbstractObjectiveTo determine if resting state functional MRI biomarkers of Alzheimer’s disease (AD) differ between older African Americans and Caucasians.MethodsWe analyzed MRI profiles from 78 individuals (31 African Americans, 47 Caucasians) with normal cognition (n=36) or mild cognitive impairment/mild AD dementia (MCI/AD, n=42). We compared AD-associated intra-network functional connectivity of the default mode network (DMN) according to race, and correlated domain-specific cognitive functions with functional connectivity which differed between the racial groups.ResultsWe identified key differences in DMN functional connectivity associated with AD between the races. Whereas MCI/AD was associated with decreased functional connectivity within the midline core DMN subsystem in older Caucasians, MCI/AD was instead associated with increased functional connectivity within the same subsystem of older African Americans. This is despite decreased functional connectivity in the medial temporal lobe DMN subsystem in both races. Memory function was also positively associated with connectivity between the precuneus and the posterior cingulate/inferior parietal lobule within the midline core subsystem, in keeping with a less amnestic-profile in older African Americans with MCI/AD.ConclusionsThese findings provide structural support that race modifies the AD phenotypes downstream from cerebral amyloid deposition, and suggests a rsf-MRI correlate of African American’s less amnestic neuropsychological profile in MCI/AD.

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.

scholarly journals Loss of functional connectivity is greater outside the default mode network in nonfamilial early-onset Alzheimer's disease variants

2015 ◽  
Vol 36 (10) ◽  
pp. 2678-2686 ◽  
Author(s):  
Manja Lehmann ◽  
Cindee Madison ◽  
Pia M. Ghosh ◽  
Zachary A. Miller ◽  
Michael D. Greicius ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Early Onset ◽  
Default Mode ◽  
Early Onset Alzheimer’S Disease

IC-P-039: RACE MODIFIES FUNCTIONAL CONNECTIVITY OF THE DEFAULT MODE NETWORK IN AGING AND ALZHEIMER'S DISEASE

2006 ◽  
Vol 14 (7S_Part_1) ◽  
pp. P40-P41
Author(s):  
Maria Misiura ◽  
William T. Hu ◽  
Jessica Turner ◽  
J Christina Howell
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Default Mode

P2-146: Temporo-parietal hypometabolism is associated with reduced functional connectivity of the default mode network in prodromal Alzheimer's disease

2015 ◽  
Vol 11 (7S_Part_11) ◽  
pp. P542-P542
Author(s):  
Lee Simon-Vermot ◽  
Yifei Zhang ◽  
Miguel Ángel Araque Caballero ◽  
Benno Gesierich ◽  
Lana Kambeitz-Ilankovic ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Default Mode ◽  
Prodromal Alzheimer’S Disease
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