Studying the Spatial Distribution of Physiological Effects on BOLD Signals Using Ultrafast fMRI.

摘要: The blood-oxygen-level dependent (BOLD) signal in fMRI reflects both neuronal activations and global physiological fluctuations. These fluctuations can be attributed to low frequency oscillations (pLFOs), respiration, cardiac pulsation. With typical TR values, i.e. 2s or longer, the high signals (i.e., from respiration pulsation) are aliased into band, making it hard study individual effect of these processes on BOLD. Recently developed multiband EPI sequences which offer full brain coverage with extremely short values (400ms less) allow spectrally separated. In this study, we applied resting state scans 9 healthy participants TR=0.4s. spatial distribution each process BOLD was explored using their spectral features independent component analysis (ICA). We found that distributions different distinct. First, pulsation affects mostly base brain, where density arteries exists. Second, prefrontal occipital areas, suggesting motion associated breathing might contribute noise. Finally, most importantly, effects pLFOs dominated many prominent ICA components, suggests that, contrary popular belief main noise source fMRI, may influential signals. Understanding measuring important for denoising accurately modeling