Spatial & Temporal Characteristics of Evoked & Induced Neural & Vascular Responses Assessed with Simultaneous EEG-fMRI

Zhongming Liu¹, Jacco A. de Zwart¹, Peter van Gelderen¹, Li-Wei Kuo¹, Jeff H. Duyn¹

Both evoked and induced neural activities contribute to the observed BOLD signal change in response to stimulus or task. By using simultaneous fMRI-EEG and frequency-tagging techniques, we found within visual cortex positive correlation between BOLD and evoked EEG power change tagged with the stimulus frequency, and negative partial correlation between BOLD and induced alpha power change in extended occipital and parietal cortices. Results suggest that stimulus (or task) yields spatially and temporally specific evoked response, as well as much less specific alteration in baseline spontaneous activity.