### Figure 10

Modulation transfer function of a canonical hemodynamic response
function (HRF), with (broken line) and without (solid line) the application of
a high-pass filter. This transfer
function corresponds to the spectral density of a white noise process after
convolution with the HRF and places constraints on the frequencies that are
survive convolution with the HRF. This
follows from convolution theorem (summarized in the equations). The insert is the filter expressed in time,
corresponding to the spectral density that obtains after convolution with the
HRF and high-pass filtering.