Correlation of zero echo time MB-SWIFT fMRI with neuronal activity during sensory stimulation in anesthetized and awake rats

Zero echo time (ZTE) fMRI with MB-SWIFT poses an artefact free alternative to traditional EPI-based BOLD fMRI approaches. However, the exact origin of the fMRI signal captured with ZTE is unknown. In this work, we investigated the correlation between electrical brain activity and the ZTE fMRI signal during sensory stimulation in anesthetized and awake rats. It is shown that a linear model explains the relationship between the fMRI signal and electrical activity in anesthetized but not in awake rats. We conclude that MB-SWIFT fMRI provides a good proxy for neuronal activity under conventional experimental conditions.