Age-related variations of the hemodynamic response function spatially resolved across human cerebral cortex

Normal aging leads to regional vascular and neural alterations. Age-related impairments in neurovascular coupling (NVC) affect the blood-oxygen-level-dependent (BOLD) hemodynamic response function (HRF) measured with functional magnetic resonance imaging, causing changes in both amplitude and temporal dynamics. Previously, global, systematic age-related changes in HRF characteristics were demonstrated, consistent with known microvascular aging effects. In this follow-up study, a standard space was used to compare spatially resolved cortical HRF dynamics between sex-balanced groups of young and older adults. The results showed substantial age-related differences in both HRF amplitude and timing across distinct cortical regions. Nearly twice as much cortical area exhibited age-related alterations in amplitude compared with timing parameters, although the spatial patterns of these effects partially overlapped. Regional HRF changes aligned with known spatial patterns of vascular aging. Overall, the findings indicate that normal aging strongly affects NVC, particularly in areas supplied by major cerebral arteries and their watershed regions.