Content area
Abstract
The purpose of this study was to investigate the relationship between functional brain networks and cognitive intraindividual variability (IIV) in healthy older adults and those with early Alzheimer’s Disease (AD). In healthy individuals, task-positive networks (TPNs), such as the dorsal attention network (DAN), show more neural recruitment in response to attention-demanding tasks than at rest, whereas the task-negative default mode network (DMN) shows the opposite pattern. The inverse relationship, or anticorrelation, between the two networks likely reflects efficient competition for cognitive resources. I hypothesized that if functional connectivity between the DAN and DMN is dysregulated in early AD, then anticorrelations will be weaker and increased cognitive IIV will occur. Neuroimaging and cognitive measures were used to assess network connectivity and IIV in healthy older adults and those with early AD. Results indicate that cognitive IIV significantly increased in individuals with early AD. Contrary to hypotheses, as IIV increased, the TPN-DMN anticorrelation strengthened, and this relationship became more negative with disease progression. These findings provide further insight into the neural and clinical manifestations of pathological aging and aid in establishing reliable methods to detect neural and behavioral differences between healthy individuals and those with early AD.
