The unbalanced Trigger induced the stable “DIANA” Signal

Motivation: The introduction of the DIANA-fMRI method has made it possible to directly detect neural activity using MRI; however, it remains highly controversial to this day. Goal(s): To explore whether the DIANA signal observed previously might be an artifact caused by the unbalanced trigger. Approach: We collected data from nine rats under continuous anesthesia with dexmedetomidine using an 11.7T animal scanner and the DIANA sequence, with and without simultaneous application of the trigger and electrical stimulation. Results: At 10 ms after the trigger, we observed a 1.5% signal increase in both the S1BF and the whole brain, regardless of whether stimulation was applied. Impact: This study demonstrated the presence of the "DIANA" Signal which was observed across the whole brain in anesthetized rats even without applying stimulations. Future DIANA-fMRI research should account for and eliminate this artifact to accurately investigate true neural activity signals.