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

## TL;DR

This study shows how aging affects blood flow responses in different parts of the human brain.

## Contribution

The paper introduces spatially resolved comparisons of HRF dynamics between young and older adults using a standard space.

## Key findings

- Age-related differences in HRF amplitude and timing were found across distinct cortical regions.
- Amplitude changes affected nearly twice as much cortical area as timing changes.
- HRF changes aligned with known vascular aging patterns in major artery-supplied regions.

## Abstract

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.