I have another question about waver.
In the afni regession pdf file, it states that if the HRF regressor has a max amplitude of 1, then the beta coefficients will represent % signal change from the mean.
when you designate each timepoint in a block as '1' in the input into waver, you end up with amplitude greater then one (even when using peak =1), because the timepoints within a block overlap, even though each block is separated in time.
can the beta coefficients still be interpreted as % signal change?
Does this interpretation depend on how you normalize your data?
In the same afni doc they normalize the timecourse to the min(200, a/b*100)
we usually normalize to ((a-b)/b)*100 does this make a difference?
Two other points. the normalization given in the doc appears to be missing a parenthese. shouldn't it be min(200,(a/b)*100)?
2) waver doesn't come close to obeying the peak =1 unless your input file is 1's and 0s, not 0's and 10's as outputed by sqwave.... is there a way to change what value is used in sqwave?
thanks,
stephanie
