Hi SPM users and developers:
I got an effect which I can not understand.
Using second order (random effect) analysis, I obtained the group maps
for activation and deactivation in a study. However, when I
extracted the
associated BOLD signals from those deactivation-mapped regions and
averaged the BOLD curves from all the subjects, I got the BOD curves
which looked like activation. They were above the baseline during
the ON periods.
It sounds too strange and I wonder how can this be explained.
Thanks,
Wen
Wen-Ching Liu, Ph.D.
Assistant Professor
Functional Imaging Laboratory
Department of Radiology
University of Medicine and Dentistry
of New Jersey-New Jersey Medical School
973-972-2281/fax: 973-972-0836
http://njms.umdnj.edu/departments/radiology/fmri/index.cfm
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