| Autor: |
Mah, Linda, Murari, Geetanjali, Vandermorris, Susan, Verhoeff, Nicolaas Paul L.G., Herrmann, Nathan |
| Zdroj: |
Alzheimer's & Dementia: The Journal of the Alzheimer's Association; Dec2020 Supplement S11, Vol. 16 Issue 11, p1-2, 2p |
| Abstrakt: |
Background: Subjective cognitive decline (SCD) increases the risk of developing Alzheimer's disease (AD) but the neural mechanisms underlying this association remain unclear. Multimodal neuroimaging studies suggest that large‐scale network disruptions occur before amyloid plaques appear in the brain, beginning with alterations in the posterior default mode network (DMN). Here we investigated the association between subjective report of memory ability and functional connectivity between the posterior DMN and medial temporal lobe structures. We hypothesized that self‐report of greater memory ability would be positively correlated with functional connectivity between the posterior DMN and the medial temporal lobe. Methods: Participants were 46 older adults [27 females, mean age=71.2 (6.5)] free of psychiatric or neurological illnesses, and normal cognition based on neuropsychological assessment. Subjective memory was evaluated using the Memory Functioning Questionnaire (MFQ). Resting state functional magnetic resonance imaging was acquired using gradient‐echo EPI BOLD at 3T and processed using CONN toolbox. A seed‐based analysis using the posterior cingulate cortex, a key node within the posterior DMN (x=‐6, y=‐52, z=40), as the seed was conducted to measure functional connectivity between the PCC and the hippocampus and parahippocampal regions. Correlations between functional connectivity measures and subjective memory [MFQ Frequency of Forgeting (MFQ‐FF)] as well as objective memory (California Verbal Learning Test‐II delayed recall) were performed. Results: MFQ‐FF scores were significantly correlated with functional connectivity between the PCC and left parahippocampal gyrus (r =.52, p <.001). MFQ‐FF scores were similarly correlated with functional connectivity between the PCC and hippocampus (r=.34, p=.02) but this finding was not statistically significantly after applying a Bonferroni correction. In contrast, CVLT delayed recall scores were not correlated with functional connectivity of the posterior DMN and the medial temporal lobe. Conclusions: Disruption of functional connectivity between the posterior DMN and the medial temporal lobe may mediate the association between SCD and AD risk. [ABSTRACT FROM AUTHOR] |
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