Abstract
BACKGROUND: This study aims to investigate the differences in neural network connectivity within the prefrontal cortex (PFC) among elderly individuals with normal cognition (NC), mild cognitive impairment (MCI), and Alzheimer's disease (AD) using functional near-infrared spectroscopy (fNIRS). RESULTS: Significant differences in functional connectivity (FC) strength were observed between the NC, MCI, and AD groups in several Brodmann areas (BA) pairs, including BA46.L-BA45.R and BA9.L-BA1.L. The most pronounced FC strength differences between the NC and MCI groups occurred at the 2nd -minute mark in BA45.R, while differences between the MCI and AD groups peaked at the 5th-minute mark in BA1.L. Additionally, the NC and MCI groups displayed FC strength differences during the first 2 minutes and first 3 minutes, again with BA45.R being central. FC strength between BA46.L-BA45.R was negatively correlated with Neuropsychiatric Inventory and Clinical Dementia Rating scores. CONCLUSIONS: FC strength in the left dorsolateral PFC, where BA46.L and BA9.L are located, emerged as a key region for cortical dysfunction in cognitive impairment. Moreover, there were differences in FC across levels of cognitive impairment, and significant correlations between differences in FC strength in BA brain regions and cognitive level.