Data from: Amyloid and cerebrovascular burden divergently influence brain functional network changes over time

Objective: To examine the effects of baseline Alzheimer’s disease and
cerebrovascular disease markers on longitudinal default mode network (DMN)
and executive control network (ECN) functional connectivity (FC) changes
in mild cognitive impairment (MCI) patients. Methods: We studied 30
amnestic (aMCI) and 55 subcortical vascular MCI (svMCI) patients with
baseline Pittsburgh Compound B (PiB)–positron emission tomography (PET)
scans and longitudinal magnetic resonance imaging (MRI) scans.
Participants were followed up clinically with annual MR imaging for up to
four years (aMCI: 26 with two time-points, 4 with three time-points;
svMCI: 13 with two time-points, 16 with three time-points, 26 with four
time-points). Results: Amyloid-β burden was associated with longitudinal
DMN FC declines, while cerebrovascular burden was associated with
longitudinal ECN FC changes. When patients were divided into PiB+ and PiB-
groups, PiB+ patients showed longitudinal DMN FC declines, while svMCI
patients showed longitudinal ECN FC increases. Direct comparisons between
the two groups without mixed pathology (aMCI PiB+ and svMCI PiB-)
recapitulated this divergent pattern: aMCI PiB+ patients showed steeper
longitudinal DMN FC declines, while svMCI PiB- patients showed steeper
longitudinal ECN FC increases. Finally, using baseline PiB uptake and
lacune numbers as continuous variables, baseline PiB uptake showed inverse
U-shape associations with longitudinal DMN FC changes in both MCI
subtypes, while baseline lacune numbers showed both mainly inverse-U shape
relationships with longitudinal ECN FC changes in svMCI patients.
Conclusions: Our findings underscore the divergent effects of amyloid-β
and cerebrovascular burden on longitudinal FC changes in the DMN and ECN
in the pre-dementia stage, which reflect the underlying pathology and may
be used to track early changes in Alzheimer’s disease and cerebrovascular
disease.