This study investigated the hemodynamic response function (HRF) of BOLD effects in white matter (WM) voxels obtained from fMRI in a resting-state. It was found that the WM HRF can be derived by reference to GM avalanche activities. The derived resting-state WM HRFs have low magnitudes, delayed onsets, and prolonged initial dips compared with GM HRF. The time delay distribution patterns and correlation coefficient profiles for WM voxels depend on the selection of the reference GM region. These findings suggest that fMRI signals in WM are associated with those in GM and encode neural activities.