A recurrent spatiotemporal pattern of fMRI (fMRI cascade) accompanied by large EEG and autonomic changes indicative of arousal modulations accounts for rsfMRI correlations with physiological signals.
Observational
Resting-state fMRI correlations with physiological and neural signals are partly driven by fMRI cascades and associated arousal modulations, highlighting the need to account for these when evaluating functional brain connectivity.
Resting-state functional magnetic resonance imaging (rsfMRI) allows the study of functional brain connectivity based on spatially structured variations in neuronal activity. Proper evaluation of connectivity requires removal of non-neural contributions to the fMRI signal, in particular hemodynamic changes associated with autonomic variability. Regression analysis based on autonomic indicator signals has been used for this purpose, but may be inadequate if neuronal and autonomic activities covary. To investigate this potential co-variation, we performed rsfMRI experiments while concurrently acquiring electroencephalography (EEG) and autonomic indicator signals, including heart rate, respiratory depth, and peripheral vascular tone. We identified a recurrent and systematic spatiotemporal pattern of fMRI (named as fMRI cascade), which features brief signal reductions in salience and default-mode networks and the thalamus, followed by a biphasic global change with a sensory-motor dominance. This fMRI cascade, which was mostly observed during eyes-closed condition, was accompanied by large EEG and autonomic changes indicative of arousal modulations. Importantly, the removal of the fMRI cascade dynamics from rsfMRI diminished its correlations with various signals. These results suggest that the rsfMRI correlations with various physiological and neural signals are not independent but arise, at least partly, from the fMRI cascades and associated neural and physiological changes at arousal modulations.
Gu et al. (Wed,) reported a observational. Concurrent rsfMRI, EEG, and autonomic indicator signals acquisition was evaluated on fMRI cascade dynamics and correlations with physiological and neural signals. A recurrent spatiotemporal pattern of fMRI (fMRI cascade) accompanied by large EEG and autonomic changes indicative of arousal modulations accounts for rsfMRI correlations with physiological signals.