Dear Tiawen,
SPM does not compute a % signal change automatically, but you can easily do
it yourself. This is a topic that has been discussed extensively, just
search the mailing list for the keyword. Here are a couple of description
that I found quite useful:
http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind04&L=SPM&P=R392137
http://marsbar.sourceforge.net/faq.html#percent_signal
Cheers,
Jan
Tianwen Chen wrote:
> Dear all,
>
> I was wondering how the SPM5 caculates the signal percentage change for a
> voxel. Is it computed against mean voxel value in a scan/session or against
> the previous voxel value? Can anyone point me to some SPM5 scripts about
> this issue? I am thinking this problem for a while and has no answer yet.
> Thanks.
>
> Tianwen Chen
>
--
Jan Gläscher, Ph.D. Div. Humanities & Social Sciences
+1 (626) 395-4976 (office) Caltech, Broad Center, M/C 114-96
+1 (626) 395-2000 (fax) 1200 California Blvd
[log in to unmask] Pasadena, CA 91125
|