Increasing MT contrast in laminar fMRI using PUSH pTx pulses

The GRE-BOLD contrast used in laminar fMRI suffers from suboptimal specificity due to unwanted extravascular effects. Recently, efforts were made to increase specificity of GRE-BOLD by means of CBV-weighting using the magnetization transfer contrast. The specificity improvement depends on the amount of selective GM signal reduction. We investigate whether PUSH pTx pulses, designed to maximize MT contrast in a given area, can achieve a higher functional contrast. Our results suggest that when opting for high-power, off-resonant MT pulses, both PUSH and a CP2+ mode perform equally well in increasing the functional contrast at short TE compared to GRE-BOLD in V1.