Dear all,

I have a question regarding basis function. Normally we take canonical HRF as a basis function and some times temporal derivative and dispersion derivative also.

If I am taking Canonical HRF and I have two condition with realignment parameters then I have 9 regressors and I can define contrast as {1 -1 0 0 0 0 0 0] or [-1 1 0 0 0 0 0 0]

But if I have also temporal and dispersion derivative what will be my contrast (either 1 or 2 or none of them) with 6 regressors for 2 conditions and 6 regressors for realignment parameters.

1)  [1 1 1 -1 -1 -1   0 0 0 0 0 0]         and     [-1 -1 -1 1 1 1   0 0 0 0 0 0]

2)  [1 0 0 -1 0 0   0 0 0 0 0 0]   and    [-1 0 0 1 0 0   0 0 0 0 0 0]

Please guide me

Thanks

Regards

NUML