In our experience with task correlated movement in simple finger tapping,
we observe that applying the spin history or any adjustment kills any
activation signal. Realigning without Adjustment, however, preserves the
activation in the motor cortex and successfully realigns the images. Of
course, there probably is error in the extent and shape of activation area,
but the results agree with what you see when the subject's movement is
minimal or not correlated with the stimulus. Speaking purely form an
empirical point of view, I think you might be OK running the realignment
without Adjustment.
Good Luck. I hope this helps.
------------------
Luis Hernandez, Ph.D.
Research Fellow
Dept. of Neurosurgery
Wake Forest University School of Medicine
Medical Center Blvd.
Winston Salem, NC 27157
Phone: (336) 713 8068
Fax: (336) 713 8588
-----Original Message-----
From: Saaussan Madi [SMTP:[log in to unmask]]
Sent: Wednesday, September 09, 1998 11:36 AM
To: [log in to unmask]
Subject: Realignment
Hello Jesper again;
>>Hence, my recommendation to you would in SPM96 jargon read as: Try to
analyse your data with and without the adjustment, which in your case
is first order adjustment with spin history.
I tried that already. The global effect i'm trying to measure varies
depending on the alignment procedure, and for some subjects the results
are opposite. The local effect does not.
The litreature has contradictory opinions about this. My guess is that
part of it is related to alignment. So simply, i'm confused.
In simple terms, Is it scientifically correct to sampling errors, if
this leads to contradictory results???
Regards;
-s madi
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