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¥ STEP
5: Perform a deconvolution analysis
on Subject EDÕs data with 
3dDeconvolve
3dDeconvolveGWhat is the
difference between regular linear regression and deconvolution analysis?
åWith linear regression, the hemodynamic response is already assumed (we can get a fixed
hemodynamic model by running the AFNI waver program)
åWith deconvolution analysis, the hemodynamic response is not assumed. Instead, it is computed by 3dDeconvolve from
the data
íOnce the HRF is
modeled by 3dDeconvolve, the program then runs a linear regression
on the data
íTo compute the
hemodynamic response function with 3dDeconvolve, we include the ÒminlagÓ
and ÒmaxlagÓ options on the command line
¥The user (you) must determine the lag time of an input
stimulus
¥1 lag = 1 TR = 2 seconds
åIn this example, the
lag time of the input stimulus has been determined to be about 15 lags
íAs such, we will add
a ÒminlagÓ of 0 and a ÒmaxlagÓ of 14 in our 3dDeconvolve command