Dear
SPMers,
We
performed an experiment on readers and pre-readers with speech
and print conditions. On second level analysis we computed null
conjunction for the 2 contrast in each group (one sample t-test)
which produced significant activation in readers while not in
pre-readers. However, when the paper was sent to review one of
the reviewers wanted us “to compute the conjunction of print and
speech on the first level and put these contrasts into a
2-sample t-test on the second-level”.
However
we came across some difficulties. If we save thresholded SPM map
from each subject when performing null conjunction in SPM
contrast manager and feed these maps to 2nd level the
model cannot be estimated and there is an error saying “there
are no inmask voxels” (even though we used very lenient
p<0.05 uncorrected threshold for the 1st level conjunction).
Is there a better way of doing multisubject conjunction?
Thank
you in advance,
-- Marek Wypych PhD Laboratory of Brain Imaging (LOBI) Neurobiology Center Nencki Institute of Experimental Biology Pasteur 3, 02-093 Warsaw, Poland Tel.: +48 22 5892 550 http://lobi.nencki.gov.pl/