Dear Qiwen,
I've recently had problems spatial normalizing structural scans since,
by default, the crosshairs were far from the AC point. To overcome this
problem, I used the display function to locate the AC and note the
co-ordinates, and then used the header edit function to paste these
co-ordinates into the 'set origin' option. I'm not sure how this relates
to functional data though.
Best wishes,
Simon.
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Simon Keller
The Magnetic Resonance and Image [log in to unmask]
Analysis Research Centre (MARIARC), Tel: 0044 (0) 151 794 5634
Pembroke Place, Fax: 0044 (0) 151 794 5634
The University of Liverpool,
L69 3BX.
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On Fri, 15 Nov 2002, qiwen mu wrote:
>Dear SPM experts:
>
>AC point is thought to be important for spatial normalization of
>functional data, however, nothing is mentioned on how to control AC
>point in SPM 99 Manual - May 2001, does this mean SPM users do not need
>to manually determine and control the AC point? if yes, how? if no, why?
>
>When I clicked the "normalization" in SPM 99, I selected "Determine
>parameters and write normalised" , subjects "1", I selected a mean EPI
>image as the "image to determine parameters", however, after I clicked
>it and "done", the mean EPI image did not display on the SPM 99
>Graphics, I did not have any opportunities to define AC point on the
>mean EPI image, instead, "images to write normalised" was asked to
>select, I selected EPI dataset to be normalized, and click "done" , then
>I selected EPI images as the "template images" . The process of spatial
>normalization looked fine.
>
>One possible way to "define" the "AC" point is click the "Display", then
>do the spatial normalization. However, wherever you "define" the point,
>e.g., the frontal pole, cerebellum, the normalized images are the
>same.
>
>I tried to change the default of spatial normalization, I could not find
>anything involved in determination of AC point.
>
>Qiwen
>
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