Brief ReportAmyloid Plaques Disrupt Resting State Default Mode Network Connectivity in Cognitively Normal Elderly
Section snippets
Methods and Materials
Community-living volunteers enrolled in longitudinal studies of memory and aging at the Washington University Alzheimer's Disease Research Center (ADRC). Participants (n = 35) meeting Clinical Dementia Rating (CDR) criteria for very mild (CDR = .5) or mild (CDR = 1) dementia of the Alzheimer type were matched for age, gender, and education with 68 individuals without cognitive impairment (CDR = 0) (Table 1). All participants in the ADRC underwent an extensive battery of neuropsychological
PIB (−) Versus AD Functional Connectivity
We first examined the functional connectivity differences in patients with early AD (n = 35) versus half of the sample without amyloid plaques (PIB−) (n = 24; randomly selected from the original 48 PIB− subjects) to generate ROIs for hypothesis testing. The group difference significance map of PIB− versus AD functional connectivity was then used for hypothesis testing in a second independent sample of 24 PIB− participants compared with PIB+ participants. As expected, significant differences
Discussion
The current finding of decreased precuneus resting state functional connectivity with hippocampus, parahippocampus, anterior cingulate, dorsal anterior cingulate, gyrus rectus, and superior precuneus extends findings of disruptions in AD and highlights the importance of integrity of the default network (3, 4, 5), since all these regions fall within the default mode network. We show here that even before cognitive impairment, cognitively normal individuals with cerebral Aβ deposits had clear-cut
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