A different interpretation of the DIANA fMRI signal

Motivation: A recent study argued that it is possible to detect neuroelectrical potentials using an fMRI scanning approach called DIANA. Although DIANA signals coincide with electrophysiological measurements, no mechanism for the effect was reportedGoal(s): We sought to implement DIANA in order to understand the origins of the reported results. Approach: We applied variants of the DIANA pulse sequence under test and control conditions, comparing results with simulations. Results: We observed DIANA signals but show that neural activity is neither necessary nor sufficient for this. Instead, the DIANA signal appears to result largely from nonideal aspects of pulse sequence timing. Impact: Our study suggests that the DIANA signal arises from an artifact in the line scan pulse sequence. This indicates possible pitfalls in implementing such sequence designs and emphasizes the continuing need for fMRI-based direct readouts of neural activity.