There shouldn't be any trouble with that many contrasts from the software
point of view, but one wonders about your experimental design if you have
40 contrasts at the first level. At the very least, you should use a
bonferroni correction *on the number of contrasts* above and beyond
whatever thresholding you do on individual maps. That is to say, if you
accept a p<0.05 corrected for multiple for comparisons for one contrast,
then you should be using p<(0.05/40) = p<0.00125 corrected, which probably
corresponds to a very high Z value (roughly 5.5).
Joseph T. Devlin, Ph. D.
FMRIB Centre, Dept. of Clinical Neurology
University of Oxford
John Radcliffe Hospital
Headley Way, Headington
Oxford OX3 9DU
Phone: 01865 222 494
Email: [log in to unmask]