Investigating the origin of negative BOLD responses using laminar CBF, CBV, T2 BOLD and CMRO2 fMRI in human visual cortex at 7T

We proposed a 7T laminar concurrent ASL, VASO and BOLD fMRI sequence to obtain quantitative CBF, CBV, T2-BOLD and CMRO2 measurements with high resolution and specificity to detect layer-dependent vascular and metabolic activities. Ipsilateral visual stimuli (eccentricity of 4°–6°) induced ring-shaped BOLD and CBF signal increase on cortical surface corresponding to the pattern of visual stimulus while decreased BOLD/CBF signals can be seen in adjacent fovea regions. In negative BOLD response (NBR) regions, moderate decrease in T2-BOLD and CBV signals and strong CBF and CMRO2 decreases especially in deep cortical layers were observed, suggesting suppressed neuronal activities in NBR regions.