[MINC-users] global t-test

[Anil Ashok Kuchinad, Mr]

Sounds good. I'll venture into these avenues when I get a chance!

Anil

----------------------------------------------------
Anil Kuchinad
Centre for Research on Pain
McGill University
Strathcona Anatomy and Dentistry Building
3640 University St., Room M/19
Montreal, Quebec , Canada
H3A 2B2
Tel: (514) 398-1271
Email: anil.kuchinad at mcgill.ca


-----Original Message-----
From: minc-users-bounces at bic.mni.mcgill.ca
[mailto:minc-users-bounces at bic.mni.mcgill.ca] On Behalf Of Sylvain MILOT
Sent: December 6, 2005 4:26 PM
To: MINC users mailing list
Subject: Re: [MINC-users] global t-test


Hello Anil,

I haven't dealt with this kind of data personnally but you may want to
have a look
here:

http://wiki.bic.mni.mcgill.ca/index.php/FullTextSearch?s=vbm

I don't know how up-to-date this is but I'm pretty certain you should
find what you're
looking for!

Now concerning glim_image, it should be feasible to use it to do exactly
what you want.
I doubt you should use the pooled sd measure since it requires that the
sd image be
stationary. Using the voxel sd measure would be more appropriate.

It should also be possible to use Keith Worsley's latest method via
fmristat's
multistat script which regularizes the random effects variance by
smoothing the ratio of
fixed+random/fixed effects SD volumes and multiplying back by the fixed
effects SD. Keith calls
this a form of local sd pooling. Look here for references
http://www.math.mcgill.ca/keith/.
If it can be tailored to PET data, it should be feasible to taylor it to
VBM data. I'm pretty sure
Jason Lerch has already done this and maybe he'll answer your call when
he
gets a chance. In the meantime look at the wiki!

Hope this helps a little,

Sylvain



On Tue, 6 Dec 2005, Anil Ashok Kuchinad, Mr wrote:

> Hello,
>
>
>
> I am running a VBM analysis and I wanted to obtain on statistic that I
> am not sure how to find. I was curious if someone knew what command
> would allow me to find an overall t-value for the comparison between
all
> grey matter voxel density in one group vs. another. I basically want
to
> find the overall difference in grey matter density across the whole
> brain between two groups.
>
>
>
> I am aware that glim_image has a pooled function but I couldn't get it
> to work for me. I am truly shooting in the dark whether I am to use
> glim_image and then run something similar to find_peaks or
> tstat_threshold later on.
>
>
>
> Hopefully this is possible!
>
>
>
> Anil
>
>
>
>
>
> ----------------------------------------------------
>
> Anil Kuchinad
>
> Centre for Research on Pain
>
> McGill University
>
> Strathcona Anatomy and Dentistry Building
>
> 3640 University St., Room M/19
>
> Montreal, Quebec , Canada
>
> H3A 2B2
>
> Tel: (514) 398-1271
>
> Email: anil.kuchinad at mcgill.ca
>
>
>
> _______________________________________________
> MINC-users at bic.mni.mcgill.ca
> http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
>

---
Sylvain Milot (sylvain at bic.mni.mcgill.ca)
              (trinity at bic.mni.mcgill.ca)
Brain Imaging Centre
Montreal Neurological Institute
Webster 2B, Room 208
Montreal, Qc., Canada, H3A 2B4
Phone  : (514) 398-4965, Fax: 398-8948
Mobile : (514) 712-1768
Office : 527 Av Des Pins O., Room 204
         Montreal, Qc., H2W 1S4


_______________________________________________
MINC-users at bic.mni.mcgill.ca
http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users