Unfortunately, I suspect these type of basic criticisms may become more common post-Eklund et al. I suspect the same effect in reviewers comments was found post-dead salmon study. Hopefully this just a phase...
Jeff
Sent from my iPhone
> On Oct 19, 2016, at 10:03 AM, Eugenio Abela <[log in to unmask]> wrote:
>
> Dear Luca,
>
> see this chapter of the Human Brain Function book and references therein:
> http://www.fil.ion.ucl.ac.uk/spm/doc/books/hbf2/pdfs/Ch8.pdf
>
> This is from spm_getSPM.m (line 83 onwards):
> % The contrast images are the weighted sum of the parameter images,
> % where the weights are the contrast weights, and are uniquely
> % estimable since contrasts are checked for estimability by the
> % contrast manager. These contrast images (for appropriate contrasts)
> % are suitable summary images of an effect at this level, and can be
> % used as input at a higher level when effecting a random effects
> % analysis.
>
> And further on (line 104):
> % For general linear model Y = XB + E with data Y, design matrix X,
> % parameter vector B, and (independent) errors E, a contrast c'B of the
> % parameters (with contrast weights c) is estimated by c'b, where b are
> % the parameter estimates given by b=pinv(X)*Y.
> %
> % Either single contrasts can be examined or conjunctions of different
> % contrasts. Contrasts are estimable linear combinations of the
> % parameters (...). SPMs are generated for the null hypotheses
> % that the contrast is zero (...)
>
> Good luck!
>
> Eugenio
|