SORDINO fMRI: contrast mechanisms and applications in awake behaving mice

Motivation: Current fMRI techniques like GRE-EPI suffer from acoustic noise, motion artifacts, and specificity, limiting their use, especially in awake "behaving" animal studies. Goal(s): To establish an fMRI method that minimizes noise and artifacts while boosting sensitivity and specificity for improved functional brain mapping. Approach: We developed SORDINO (Steady-state On-the-Ramp Detection of INduction-decay with Oversampling) on a 9.4T MRI system, utilizing a constant gradient amplitude and continuous directional change throughout, and directly samples FID with maximal acquisition efficiency. Results: SORDINO outperformed conventional methods, offering silent, artifact-resistant imaging with robust sensitivity, enabling high-quality functional brain mapping in awake behaving mice. Impact: This study introduces SORDINO, a transformative fMRI technique that measures non-BOLD contrast. SORDINO enables precise, artifact-resistant, sensitive, and silent brain mapping in awake behaving subjects, enabling neuroimaging studies that were previously challenging or impossible.