Dear SPM experts!
We are performing a bloc design fMRI experiment with 4 sessions/subject
(100 scans/session TR 3 sec).
Each session consists of 10 blocs (each of ~10 scans length)
The order of conditions is as follows:
session 1: E C B D A C A D E B
session 2: A D B C E B E D A C
session 3: B A E D C B E A C D
session 4: C D E A B A E B D C
We built a design matrix with 5 different conditions, variable SOA's and
variable durations, defining the blocs as events of different length.
SPM now offers us a default high pass filter of 177 213 176 152 sec.
We do not understand how these cut offs are calculated and why they
differ that much between sessions. (if it is calculated as twice the
minimum of the maximum interval between corresponding conditions as
mentioned in earlier mails we would suppose a cut off of 120 sec for
session 1 3 4).
Any help would be very much appreciated
Thank you very much in advance
Bernhard
Dr. B. Haslinger
Neurologische Klinik
TU München
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