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.