Nurhan Erbil1, Gopikrishna Deshpande1, 2
1Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States; 2Department of Psychology, Auburn University , Auburn, AL, United States
Resting state networks, as coherent low frequency fluctuations of fMRI, are correlated with smoothed and downsampled EEG microstates. This coupling between EEG and fMRI can be attributed to scale free fractal properties of EEG microstates. By using fractal analysis of simultaneously acquired EEG and fMRI, we examined the existence of scale free dynamics in fMRI in addition to EEG. Simultaneously acquired resting state EEG and fMRI data from 4 subjects were analyzed by Cartool software and subjected to microstate segmentation for each subject and modality separately. Random walk embedding was applied to microstate segmentation sequences and corresponding Hurst exponents were calculated. We have shown both EEG and fMRI have scale free dynamics indicating a relation between resting state fMRI fluctuations and electrical oscillations underlying fast neuronal processes.