> is there an option for unequal spacing of the intervals, i.e. to have more beta
> weights for the interesting first 20s than for the post-stimulus response?

One approach I can think of is to artificially break each block into two trial types (as well as their timings): the first has a duration of 20s, and the other starts at the end of the 20s block. Then you can arrange different basis intervals between the two.

To save some degrees of freedom, TENTzero and CSPLINzero may be a better option.

> How can I then compare the outputs (-iresp) of these two experiments and make
> statements about nonlinearities in scaling etc if they are so unequally spaced/computed?

Between the one with instantaneous events and the one with blocks of 20s? Comparing nonlinearities in what sense? At subject or group level?

Hope someone else will chime in regarding your 3dNLfim question.

Gang



Edited 1 time(s). Last edit at 08/05/2013 11:00AM by Gang.