In the paper 'BASCO: a toolbox for task-related functional connectivity', estimation of the "amplitude of effects" is proposed as:
β = sign(β1) * sqrt(β1^2 + β2^2 + β3^2), where, the first beta-value relates to the canonical HRF, the second and third beta-values relate to the first and second temporal derivative, respectively.

I was wondering how to set or create the [color=#ff0000]β3. Then I check the BASCO.m, where in the 1270 to 1272[/color] lines  of the script, it is commented:
% Estimating the "amplitude" of the effects at each voxel = sign(V1).*sqrt(V1.^2+V2.^2)
% where V1 is the canonical effect contrast volume, and V2 is the temporal derivative
% effect contrast volume. [Calhoun (2004)]

[color=#ff0000]β3 seems not included in the [/color]formula in the comment, and in the following line 1282 of the script:
datmat = sign(datmatA).*sqrt(datmatA.^2+datmatB.^2+datmatC.^2)
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The 'datmatC' seems corresponding to 'β3', but it more likely a disperion derivatives while not the second temporal derivative.

My question is, in which way the BASCO estimating the "amplitude of effects", and by which way the second temporal derivative of HRF could be used, or if I have just misunderstood the script?
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