Exploring Brain Functional Connectivity in Cognitively Healthy Individuals with Pathological CSF Amyloid/Tau

Background Disrupted brain connectivity precedes cognitive impairment in Alzheimer’s disease (AD), affects self‐regulation and executive functions, and can be revealed by quantitative electroencephalography (qEEG). Neuroimaging research on AD progression has demonstrated structural and functional abnormalities in specific brain regions and connections. However, little is known about the changes in directional functional connectivity in pre‐symptomatic AD. We aim to explore the information flow in pre‐symptomatic AD during cognitive flexibility challenge. Method During a task‐switching challenge, 21‐head channel EEG was recorded from 55 cognitively healthy individuals classified into two groups (9 were excluded from artifacts or suboptimal performance): with an abnormal (CH‐PAT, n = 27) versus normal (CH‐NAT or controls, n = 19) ratio of cerebrospinal fluid (CSF) amyloid/total‐tau. In the task‐switching paradigm, each trial included two stimuli, and participants were required to either name the ink color or read the word when color words were printed in different colors of ink. Only correctly responded trials were analyzed. Directed functional connectivity between brain regions was estimated with Partial Directed Coherence (PDC) in frontal, central, parietal, temporal, and occipital regions in alpha frequency band (8‐12 Hz) during word‐color trials. Two‐sided t‐tests were conducted, with p