Hi Sarah
> I am trying to run a full factorial analysis on SPM5 for grey matter
> volumes, but I am stuck on the contrasts
>
> In the design matrix, I have the following
>
> Column1 - Group1
> Column2 - Group2
> Column3 - Total Grey Matter (which I want to co-vary out)
> Column4 - Behavioural score
>
> I am trying to ascertain the effect of the behavioural scores on the
> grey matter volumes for both groups.
> I tried 1 1 0 -1, but that didn't seem to work
>
try a multiple regression model with
column 1 groups (11111-1-1-1-1-1)
column 2 behavior group1 (xxxxx000000)
column 3 behavior group 2 (00000xxxxx)
column 4 GM volumes
example of contrasts
1 0 0 0 = voxels with a diff between groups
0 1 0 0 = voxels with a sig + corr for group 1
0 0 1 0 = voxels with a sig + corr for group 2
0 1 -1 0 = voxels with corr gp 1 > corr gp 2 (you may want to exclude
here voxel not sig corr in gp1 and gp2)
0 1 1 0 = voxels with sig + corr across gps
....
cyril
> Please help
>
> Many Thanks
>
> Sarah
>
>
>
--
Dr Cyril Pernet,
fMRI Lead Researcher SINAPSE
SFC Brain Imaging Research Center
Division of Clinical Neurosciences
University of Edinburgh
Western General Hospital
Crewe Road
Edinburgh
EH4 2XU
Scotland, UK
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tel: +44(0)1315373661
http://www.sbirc.ed.ac.uk/cyril
http://www.sinapse.ac.uk/
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
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