Hello everyone,
I have a question concerning the timing of events when you are
scanning with a sparse-sampling scan protocol.
We used a sparse sampling protocol to be able to measure EMG
between scanning 2 volumes (we scanned a volume in 3 seconds -
followed by 2 seconds without scanning). During the 2 seconds
between volumes subjects produce force as well.
When we specify a model, we say that the interscan interval is 5
secs. However, then we have a problem: we cannot "tell" SPM that
the duration of a volume is only 3 secs. Thus, if we say that an event
started at scan 0.6: that means that the event started after 3 secs,
thus after the first volume was taken, how will SPM handle this?
Does SPM assume that the total volume took 5 seconds, and that
the event started halfway the volume? Or is there a way to tell SPM
what exactly happened?
I hope someone can help me.
Best regards,
Hiske
Hiske van Duinen
PhD-student
Dept. Medical Physiology, RUG
A. Deusinglaan 1, 9713 AV Groningen,
The Netherlands
phone: -31 50 363 8735
fax : -31 50 363 2751
email: [log in to unmask]
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