Analysis of a Phase Spectrum Method for fMRI Time Series Via the Hilbert Transform

A phase spectrum (PS) method is presented to identify brain functional activation areas via using the phase information of functional magnetic resonance imaging (fMRI) time series. The basic idea is that the phase at the characteristic frequency of fMRI signal is specified as brain activation index. The developed phase approach is tested and confirmed by the result from both simulation and in vivo fMRI data.