Dear Maria,
> I had posted a question earlier regarding fractional signal change, and now
> realize that this is actually the % signal change. I understand that for my
> fMRI data using SPM99 I can, Plot > fitted and adjusted responses > choose my
> contast > plot against scan or time > this gives me a graph of % signal change
> over time.
I would be careful with interpreting the values plotted this way as
percent signal change. There have been several previous discussions on
the list regarding this, and there still is some ambiguity around the
definition of "percent signal change". I would recommend searching the
list for relevant postings and reviewing them, e.g., you can start from:
http://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind0010&L=spm&D=0&P=4045
http://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind0104&L=spm&D=0&P=27929
Best,
Kalina
--
_____________________________________________________________________________
Kalina Christoff, Ph.D. Email: [log in to unmask]
Office: Rm.422; (650) 725-0797
Department of Psychology Home: (408) 245-2579
Jordan Hall, Main Quad Fax: (650) 725-5699
Stanford, CA 94305-2130 http://www-psych.stanford.edu/~kalina/
_____________________________________________________________________________
|