def dspmt(t):
t = np.asarray(t)<EOL>return spmt(t) - spmt(t - <NUM_LIT:1>)<EOL>
SPM canonical HRF derivative, HRF derivative values for time values `t`

    This is the canonical HRF derivative function as used in SPM.

    It is the numerical difference of the HRF sampled at time `t` minus the
    values sampled at time `t` -1