Dear Volkmar,

Thank-you for your reply. Multiple regression was my first thought, however, I am confused as to how to enter the scans for the 2 groups in the multiple regression model in SPM5 (unlike the two-sample t-test, where it asks for scans for Group 1 and Group 2, the multiple regression only has an entry for "scans").

Thank-you for your help,

Julie 

Julie E. McEntee, M.A., C.C.R.P.
Senior Research Program Coordinator
Department of Psychiatry- Neuroimaging
Johns Hopkins University School of Medicine
600 N. Wolfe St./ Phipps 300
Baltimore, MD 21287
Phone: 410-502-0468
Fax: 410-614-3676

----- Original Message -----
From: Volkmar Glauche <[log in to unmask]>
Date: Wednesday, January 7, 2009 9:34 am
Subject: Re: [SPM] fMRI 2nd-level analysis with covariates
To: Julie E McEntee <[log in to unmask]>
Cc: [log in to unmask]


> Dear Julie,
>  
>  there are many different ways to model this: you could use a 2-sample
>  t-test and include the FA vector as covariate. Alternatively, you could
>  enter both "years of education" and FA as covariates in a multiple
>  regression model. To assess correlation with the FA vector, you would
>  simply weight its column with "1", and the other columns with "0".
>  
>  Hope this helps,
>  
>  Volkmar
>  
>  
>  Am Montag, den 05.01.2009, 12:02 -0500 schrieb Julie E McEntee:
>  > It's a vector containing the mean FA value for each subject.
>  > 
>  > Julie E. McEntee, M.A., C.C.R.P.
>  > Senior Research Program Coordinator
>  > Department of Psychiatry- Neuroimaging
>  > Johns Hopkins University School of Medicine
>  > 600 N. Wolfe St./ Phipps 300
>  > Baltimore, MD 21287
>  > Phone: 410-502-0468
>  > Fax: 410-614-3676
>  > 
>  > ----- Original Message -----
>  > From: "MCLAREN, Donald" <[log in to unmask]>
>  > Date: Monday, January 5, 2009 11:50 am
>  > Subject: Re: [SPM] fMRI 2nd-level analysis with covariates
>  > To: Julie E McEntee <[log in to unmask]>
>  > 
>  > 
>  > > Is the covariate of interest the FA value extracted from a region 
> or 
>  > > the FA
>  > >  value at each voxel?
>  > >  
>  > >  On Mon, Jan 5, 2009 at 10:38 AM, Julie E McEntee 
> <[log in to unmask]> 
>  > > wrote:
>  > >  
>  > >  > Hello SPMers,
>  > >  >
>  > >  > I am using the latest version/update of SPM5 with MatLab 7.0 
> on 
>  > > Windows XP
>  > >  > Professional 2002, service pack 3.
>  > >  >
>  > >  > I have 1st-level analyses (.con hdr/image files) consisting of 
> the
>  > >  > difference between 2 task conditions for each of 2 groups 
> (patients 
>  > > and
>  > >  > controls).
>  > >  >
>  > >  > There is a statistically significant difference between the 2 
> 
>  > > groups in
>  > >  > years of education. I would like to include this as a 
> "nuisance" 
>  > > variable at
>  > >  > 2nd-level analysis. I would also like to include a "covariate 
> of interest"
>  > >  > (in this case fractional anisotrophy- FA). There is no 
> correlation 
>  > > between
>  > >  > these 2 variables.
>  > >  >
>  > >  > What test should I use at the 2nd-level (and subsequent 
> definition 
>  > > of
>  > >  > contrast weights) to answer the queston:
>  > >  >
>  > >  > Is FA related to the difference in BOLD response between groups?
>  > >  >
>  > >  > Thank-you for your help,
>  > >  >
>  > >  > Julie
>  > >  >
>  > >  > Julie E. McEntee, M.A., C.C.R.P.
>  > >  > Senior Research Program Coordinator
>  > >  > Department of Psychiatry- Neuroimaging
>  > >  > Johns Hopkins University School of Medicine
>  > >  > 600 N. Wolfe St./ Phipps 300
>  > >  > Baltimore, MD 21287
>  > >  > Phone: 410-502-0468
>  > >  > Fax: 410-614-3676
>  > >  >
>  > >  
>  > >  
>  > >  
>  > >  -- 
>  > >  Best Regards, Donald McLaren
>  > >  =====================
>  > >  D.G. McLaren
>  > >  University of Wisconsin - Madison
>  > >  Neuroscience Training Program
>  > >  Office: (608) 265-9672
>  > >  Lab: (608) 256-1901 ext 12914
>  > >  =====================
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>  > 
>  -- 
>  Volkmar Glauche
>  -
>  Department of Neurology         [log in to unmask]
>  Universitaetsklinikum Freiburg  Phone   49(0)761-270-5331
>  Breisacher Str. 64              Fax     49(0)761-270-5416
>  79106 Freiburg                  
>  
>