Hippocampal connectivity with retrosplenial cortex drives neocortical tau accumulation and memory function

Abstract The mechanisms underlying accumulation of Alzheimer’s disease (AD)-related tau pathology outside of the medial temporal lobe (MTL) in older adults are unknown but crucial to understanding cognitive decline. Neural connectivity has recently been implicated in the propagation of tau in humans, consistent with data from animal studies. Using resting state functional connectivity and tau PET imaging, we examined MTL structures involved in medial parietal tau deposition in cognitively normal older adults. Functional connectivity between retrosplenial cortex and hippocampus, but not entorhinal cortex, correlated with tau in medial parietal lobe. Further, hippocampal-retrosplenial connectivity strength modulated the correlation between MTL and medial parietal lobe tau, as well as between medial parietal tau and episodic memory. Medial parietal tau spread thus reflects patterns of neural connectivity that represent a critical step in the evolution of cognitive dysfunction in aging and AD.

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The effect of amyloid deposition on longitudinal resting-state functional connectivity in cognitively normal older adults

Alzheimer s Research & Therapy ◽

10.1186/s13195-019-0573-1 ◽

2020 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Chemin Lin ◽

Maria Ly ◽

Helmet T. Karim ◽

Wenjing Wei ◽

Beth E. Snitz ◽

...

Keyword(s):

Neural Networks ◽

Older Adults ◽

Cognitive Function ◽

Functional Connectivity ◽

Resting State ◽

Clinical Symptoms ◽

Rate Of Change ◽

Resting State Functional Connectivity ◽

Cognitive Changes ◽

Cognitively Normal

Abstract Background Pathological processes contributing to Alzheimer’s disease begin decades prior to the onset of clinical symptoms. There is significant variation in cognitive changes in the presence of pathology, functional connectivity may be a marker of compensation to amyloid; however, this is not well understood. Methods We recruited 64 cognitively normal older adults who underwent neuropsychological testing and biannual magnetic resonance imaging (MRI), amyloid imaging with Pittsburgh compound B (PiB)-PET, and glucose metabolism (FDG)-PET imaging for up to 6 years. Resting-state MRI was used to estimate connectivity of seven canonical neural networks using template-based rotation. Using voxel-wise paired t-tests, we identified neural networks that displayed significant changes in connectivity across time. We investigated associations among amyloid and longitudinal changes in connectivity and cognitive function by domains. Results Left middle frontal gyrus connectivity within the memory encoding network increased over time, but the rate of change was lower with greater amyloid. This was no longer significant in an analysis where we limited the sample to only those with two time points. We found limited decline in cognitive domains overall. Greater functional connectivity was associated with better attention/processing speed and executive function (independent of time) in those with lower amyloid but was associated with worse function with greater amyloid. Conclusions Increased functional connectivity serves to preserve cognitive function in normal aging and may fail in the presence of pathology consistent with compensatory models.

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Relationship between Stroop performance and resting state functional connectivity in cognitively normal older adults.

Neuropsychology ◽

10.1037/a0033402 ◽

2013 ◽

Vol 27 (5) ◽

pp. 516-528 ◽

Cited By ~ 24

Author(s):

Janet M. Duchek ◽

David A. Balota ◽

Jewell B. Thomas ◽

Abraham Z. Snyder ◽

Patrick Rich ◽

...

Keyword(s):

Older Adults ◽

Functional Connectivity ◽

Resting State ◽

Resting State Functional Connectivity ◽

Cognitively Normal

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

Alzheimer s & Dementia ◽

10.1002/alz.046693 ◽

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

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Altered Functional Connectivity Patterns of Parietal Subregions Contribute to Cognitive Dysfunction in Patients with White Matter Hyperintensities

Journal of Alzheimer s Disease ◽

10.3233/jad-210315 ◽

2021 ◽

pp. 1-11

Author(s):

Qiang Wei ◽

Shanshan Cao ◽

Yang Ji ◽

Jun Zhang ◽

Chen Chen ◽

...

Keyword(s):

White Matter ◽

Functional Connectivity ◽

White Matter Hyperintensities ◽

Parietal Lobe ◽

Small Vessel Disease ◽

Anterior Cingulate ◽

Healthy Controls ◽

Cingulate Gyrus ◽

Anterior Cingulate Gyrus ◽

Resting State Functional Connectivity

Background: The white matter hyperintensities (WMHs) are considered as one of the core neuroimaging findings of cerebral small vessel disease and independently associated with cognitive deficit. The parietal lobe is a heterogeneous area containing many subregions and play an important role in the processes of neurocognition. Objective: To explore the relationship between parietal subregions alterations and cognitive impairments in WHMs. Methods: Resting-state functional connectivity (rs-FC) analyses of parietal subregions were performed in 104 right-handed WMHs patients divided into mild (n = 39), moderate (n = 37), and severe WMHs (n = 28) groups according to the Fazekas scale and 36 healthy controls. Parietal subregions were defined using tractographic Human Brainnetome Atlas and included five subregions for superior parietal lobe, six subregions for inferior parietal lobe (IPL), and three subregions for precuneus. All participants underwent a neuropsychological test battery to evaluate emotional and general cognitive functions. Results: Differences existed between the rs-FC strength of IPL_R_6_2 with the left anterior cingulate gyrus, IPL_R_6_3 with the right dorsolateral superior frontal gyrus, and the IPL_R_6_5 with the left anterior cingulate gyrus. The connectivity strength between IPL_R_6_3 and the left anterior cingulate gyrus were correlated with AVLT-immediate and AVLT-recognition test in WMHs. Conclusion: We explored the roles of parietal subregions in WMHs using rs-FC. The functional connectivity of parietal subregions with the cortex regions showed significant differences between the patients with WMHs and healthy controls which may be associated with cognitive deficits in WMHs.

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