Dear all,
I am running an analysis with parametric modulations. The contrast "1"
is supposed to reveal areas with
increasing signal while "-1" with decreasing signal
(https://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind05&L=SPM&P=R168802).
However, when I plot the contrast "-1", I am getting some areas with increasing
activation and other areas decreasing. You can see the effect at the
attached pictures. How is this possible?
I have observed that the attached examples are one for for response at
5.1 seconds and the other at 15.8 seconds. This is
how SPM plots that, I just used the plot button.
Any clue on what kind of modulations I am getting?
Dorian.
PhD Student
Ruhr University Bochum.
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