Amyloid-Beta Influences Memory via Functional Connectivity During Memory Retrieval in Alzheimer's Disease.
Front Aging Neurosci
; 13: 721171, 2021.
Article
em En
| MEDLINE
| ID: mdl-34539382
ABSTRACT
Objective:
Amnesia in Alzheimer's disease (AD) appears early and could be caused by encoding deficiency, consolidation dysfunction, and/or impairment in the retrieval of stored memory information. The relationship between AD pathology biomarker ß-amyloid and memory dysfunction is unclear.Method:
The memory task functional MRI and amyloid PET were simultaneously performed to investigate the relationship between memory performance, memory phase-related functional connectivity, and cortical ß-amyloid deposition. We clustered functional networks during memory maintenance and compared network connectivity between groups in each memory phase. Mediation analysis was performed to investigate the mediator between ß-amyloid and related cognitive performance.Results:
Alzheimer's disease was primarily characterized by decreased functional connectivity in a data-driven network composed of an a priori default mode network, limbic network, and frontoparietal network during the memory maintenance (0.205 vs. 0.236, p = 0.04) and retrieval phase (0.159 vs. 0.183, p = 0.017). Within the network, AD had more regions with reduced connectivity during the retrieval than the maintenance and encoding phases (chi-square p = 0.01 and < 0.001). Furthermore, the global cortical ß-amyloid negatively correlated with network connectivity during the memory retrieval phase (R = - 0.247, p = 0.032), with this relationship mediating the effect of cortical ß-amyloid on memory performance (average causal mediation effect = - 0.05, p = 0.035).Conclusion:
We demonstrated that AD had decreased connectivity in specific networks during the memory retrieval phase. Impaired functional connectivity during memory retrieval mediated the adverse effect of ß-amyloid on memory. These findings help to elucidate the involvement of cortical ß-amyloid (Aß) in the memory performance in the early stages of AD.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article