Jeroen Cornelis Willem Siero1,2, Nick F. Ramsey1, Johannes Marinus Hoogduin1,2, Peter R. Luijten2, Natalia Petridou1,2
1Rudolf Magnus Institute, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands
Understanding the neurovascular coupling mechanism underlying the BOLD fMRI signal is contingent on the accurate spatial and temporal characterization of the hemodynamic impulse response (HIR), linked to the microvasculature. We obtained the spin-echo (SE) HIR at 7T using very short visual stimuli and high temporal resolution, and compared it to gradient-echo (GE) HIR obtained near the pial surface and deeper gray matter (dGM). SE HIR delay matched that of GE HIR in dGM, but the width was much narrower. The SE HIR can lead to new insights to the factors that contribute to the GE HIR.