scholarly journals Subjective memory ability correlates with functional connectivity between the medial temporal lobe and posterior default mode network in cognitively normal older adults

2020 ◽  
Vol 16 (S5) ◽  
Author(s):  
Linda Mah ◽  
Geetanjali Murari ◽  
Susan Vandermorris ◽  
Nicolaas Paul L.G. Verhoeff ◽  
Nathan Herrmann
Keyword(s):  
Older Adults ◽  
Functional Connectivity ◽  
Temporal Lobe ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Subjective Memory ◽  
Cognitively Normal ◽  
Memory Ability ◽  
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 AEROBIC TRAINING, THE DEFAULT MODE NETWORK, AND COGNITION IN OLDER ADULTS WITH MILD VASCULAR COGNITIVE IMPAIRMENT

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S55-S55
Author(s):  
Rachel A Crockett ◽  
Chun Liang Hsu ◽  
Cindy Barha ◽  
Ging-Yuek Robin Hsiung ◽  
Teresa Liu-Ambrose
Keyword(s):  
Older Adults ◽  
Cognitive Impairment ◽  
Cognitive Function ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Resting State ◽  
Aerobic Training ◽  
Vascular Cognitive Impairment ◽  
Default Mode ◽  
Global Cognitive Function

Abstract Aerobic training has been shown to be effective at improving cognitive and brain outcomes in older adults with mild subcortical ischemic vascular cognitive impairment (SIVCI). However, uncertainty remains regarding the underlying neurobiological mechanisms by which exercise elicits these improvements in cognition. Increased aberrant functional connectivity of the default mode network has been highlighted as a factor contributing to cognitive decline in older adults with cognitive impairment. Greater connectivity of the DMN at rest is associated with poorer performance on attention-demanding tasks, indicative of a lack of ability to deactivate the network on task. Our previous work on a randomized controlled trial of participants with mild SIVCI, demonstrated that 6-months of thrice weekly aerobic training led to improved global cognitive function, as measured by Alzheimer’s disease Assessment Scale-Cognitive subscale (ADAS-Cog), compared with a health education program. Thus, we conducted secondary analyses to investigate whether these changes in global cognitive function were associated with changes in resting state DMN connectivity. A subsample of 21 participants underwent a resting state functional magnetic resonance imaging (fMRI) scan before and after trial completion. Change in resting state DMN connectivity was found to significantly predict change in ADAS-Cog score (β = -.442, p=.038) after controlling for age, intervention group, and baseline functional capacity (R2=.467, F(4,16)= 3.507, p=.031). These findings suggest that functional connectivity of the DMN may underlie changes in global cognitive function. Furthermore, aerobic exercise is a promising intervention by which to elicit these changes in older adults with mild SIVCI.

scholarly journals Relationships between default-mode network connectivity, medial temporal lobe structure, and age-related memory deficits

2015 ◽  
Vol 36 (1) ◽  
pp. 265-272 ◽  
Author(s):  
Andrew M. Ward ◽  
Elizabeth C. Mormino ◽  
Willem Huijbers ◽  
Aaron P. Schultz ◽  
Trey Hedden ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Network Connectivity ◽  
Memory Deficits ◽  
Default Mode ◽  
Age Related

scholarly journals What can narratives tell us about the neural bases of human memory?

2020 ◽  
Author(s):  
Hongmi Lee ◽  
Buddhika Bellana ◽  
janice chen
Keyword(s):  
Temporal Lobe ◽  
Neural Activity ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Activity Patterns ◽  
Human Memory ◽  
Memory System ◽  
Situation Models ◽  
Neural Synchrony ◽  
Default Mode

Narratives are increasingly used to study naturalistic human memory and its brain mechanisms. Narratives—audiovisual movies, spoken stories, and written stories—consist of multiple inter-related and temporally unfolding events which are rich in semantic and emotional content. These characteristics drive intersubject neural synchrony in the default mode network, where abstract situation models are represented and reinstated. Medial temporal lobe structures interact with the cortical sub-regions of the default mode network to support the encoding and recall of narrative events. Narrative memories are frequently communicated across individuals, resulting in the transmission of experiences and neural activity patterns between people. Recent advances in neuroimaging and naturalistic stimulus analysis provide valuable insights into narrative memory and the human memory system in general.

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