Modeling the predicted response to oscillatory stimuli dependent on the HRF. (A) Example of a range of HRF waveforms with differing parameters used for convolution. (B) Frequency response at 0.5 Hz using each HRF, normalized to the frequency response obtained with the SPM HRF. (C) The flow input to the balloon model was a single cycle of a sinusoid of different frequencies. (D) When τv (the time constant for the viscoelastic effects) is set to zero, the predicted response has wide dispersion for all input durations. (E) When τv is set to 30 s, briefer stimuli elicit sharper BOLD responses. (F) When the mean transit time (τMTT) is decreased, the BOLD response again becomes sharper, and dispersion is reduced.