Differential effects of aquaporin-4 channel inhibition on BOLD fMRI and Diffusion fMRI responses in rat visual cortex

The contribution of astrocytes to the BOLD fMRI and DfMRI responses in visual cortex of mice following visual stimulation were investigated an aquaporin 4 (AQP4) channel blocker, TGN-020, acting as an astrocyte function perturbator. Under TGN-020 injection the amplitude of the BOLD fMRI response became significantly higher.In contrast, no significant changes in the DfMRI responses and the electrophysiological responses were observed. Those results further confirm the implications of astrocytes in the neurovascular coupling mechanism underlying BOLD fMRI, while DfMRI relies on other, not astrocyte-mediated mechanisms.