The frequency profile of TE-dependent BOLD physiological fluctuations
Murphy K, Birn R, Bandettini P
National Institute of Mental Health
By examining multi-echo time series data, TE-dependent physiological noise can be separated from non-TE dependent noise sources creating a potential method to cleanly separate BOLD from non-BOLD (and therefore non-neuronal) fluctuations. We investigate this technique further by characterizing the frequency components of the TE dependent and independent signal changes. We found that the TE-dependent BOLD-related physiological fluctuations are primarily at low frequencies, suggesting perhaps spontaneous neuronal activity. However, the results indicate that several non-neuronally related fluctuations also show a TE dependence making it difficult to cleanly separate neuronal from non-neuronal physiological noise.