Laminar BOLD normalization using breath-hold challenge

Limitations of the several developed laminar fMRI acquisition methods and pial and intra-cortical ascending vein contamination of the gradient-echo (GE) restrict the neural specificity of the depth profiles. Preserving the advantage of high sensitivity of the GE-EPI sequence, we propose a simple and intuitive model to normalize laminar BOLD with breath holding. Our normalization method increased specificity of the BOLD activation map and emphasized laminar BOLD signal changes in gray matter regions by suppressing signal changes from CSF. This approach takes into account the different vascular sensitivity across layers but may not fully account for the draining vein contamination.