Ultra-Fast fMRI Reveals High-Frequency Fluctuations in Response to Neuronal Discharges

Pierre LeVan¹, Julia Jacobs², Vasumathi Jayakumar¹, Jrgen Hennig¹

FMRI hemodynamics are generally assumed to be prolonged and slow-varying at timescales of several seconds and can thus be adequately sampled at conventional fMRI temporal resolutions of 2-3 seconds. In contrast, the current study investigates high-frequency (>0.5Hz) fMRI fluctuations measured by the whole-brain ultra-fast MR-encephalography (MREG) sequence (100ms temporal resolution), following epileptic discharges recorded by EEG. In 67% of the analyzed spike types, a cluster of voxels showing significant high-frequency fluctuations following the spikes could be identified in brain regions concordant with the spike field. MREG opens up new avenues for the localization of neuronal activity with high spatiotemporal resolution.