Dear Krish:
Thank you very much for your help.
The question about the use of "Ancova" or "Scaling" seems not be addressed
in the discussion. Is there any answer regarding to it?
Sincerely
Ming-Ting
............................................................................
...............................................................
Ming-Ting Wu, MD Tel: (O)886-7-3422121 ext 6205,
6235, 6212, 6201
Dept. of Radiology Tel: (H) 886-7-3461096 Fax:(O)
886-7-3468301
Kaohsiung Veterans General Hospital
386 Ta-chung 1st Rd. Kaohsiung 813, Taiwan
----- Original Message -----
寄件者: Krish <[log in to unmask]>
收件者: Wu, Ming-Ting <[log in to unmask]>
副本: SPM <[log in to unmask]>
傳送日期: 2000年3月28日 PM 06:44
主旨: Re: global normalization
> Dear Ming-Ting,
>
> I found some similiar effects and raised a similiar query on the SPM
mailbase:
>
> http://www.mailbase.ac.uk/lists/spm/2000-01/0107.html
>
> I received some useful advice/comments from:
>
> Steve Smith:
> http://www.mailbase.ac.uk/lists/spm/2000-01/0108.html
>
> and Kent Kiehl
> http://www.mailbase.ac.uk/lists/spm/2000-01/0113.html
>
> See also Jesper Andersson's posting:
> http://www.mailbase.ac.uk/lists/spm/1999-11/0152.html
>
> Good luck!
>
> Krish
>
>
> "Wu, Ming-Ting" wrote:
>
> > Dear Group:
> > I have basic questions about the option of global normalization.
> > 1. what is the indication for use of none, scaling for global
normalization
> > in SPM99?
> > 2. Why does the "ancova" in SPM96 be removed?
> > 3. I compared the result of using scaling, ancova and none for a
> > somatosensory stimulation, with a realigned-only dataset for references;
> > please see the attached files
> > Fig.1 : the result of realigned, non-smoothed, non-normalized data with
a
> > very simple correlation map
> > Fig.2: same of fig.1, representive slice showing right parietal
activation
> > and its time-course.
> > Fig.3: render map with ancova normalization, the parietal activation is
> > there.
> > Fig.4: render map with scaling global normalization, the parietal
activation
> > removed a lot, more deactivation spots now.
> > Fig.5 render map without global normalization. large activations noted.
> >
> > >From figure 1, 2, my feeling is that there really have strong
activation,
> > corresponding to somatosensory stimulation of left leg. it seems to be
close
> > to that shown on the map with Ancova. The map with scaling seems to be
too
> > restrictive, and have more deactivation (blue color) than other maps;
Is
> > the deactivation true or not?
> >
> > Thank you in advance
> >
> > Sincerely
> >
> > Ming-Ting
> >
> >
............................................................................
> > ...............................................................
> > Ming-Ting Wu, MD Tel: (O)886-7-3422121 ext
6205,
> > 6235, 6212, 6201
> > Dept. of Radiology Tel: (H) 886-7-3461096
Fax:(O)
> > 886-7-3468301
> > Kaohsiung Veterans General Hospital
> > 386 Ta-chung 1st Rd. Kaohsiung 813, Taiwan
> >
>
------------------------------------------------------------------------
> > Name: Fig5_nonegobal.tif
> > Fig5_nonegobal.tif Type: TIFF Image (image/tiff)
> > Encoding: base64
> >
> > Name: Fig2_realign_correlate.tif
> > Fig2_realign_correlate.tif Type: TIFF Image (image/tiff)
> > Encoding: base64
> >
> > Name: Fig3_ancova.tif
> > Fig3_ancova.tif Type: TIFF Image (image/tiff)
> > Encoding: base64
> >
> > Name: Fig4_scaling.tif
> > Fig4_scaling.tif Type: TIFF Image (image/tiff)
> > Encoding: base64
> >
> > Name: Fig1_correlate_whole.tif
> > Fig1_correlate_whole.tif Type: TIFF Image (image/tiff)
> > Encoding: base64
>
> --
> Dr Krish Singh, ([log in to unmask])
> Magnetic Resonance and Image Analysis Research Centre, Liverpool
University
> Pembroke Place, Liverpool, L69 3BX, UK. Tel 0151 7945645. Fax 0151 794
5635
>
>
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