Gabriel
> Dear SPM experts
> When performing across and within correlation analyses I can define
> the direction of my regressors of interest. However, this is not
> applicable for correlations between groups. Is there any way to get
> this information?
it's always poosible - in your VBM if you use t contrasts with values
only for regressors of one group it gives the within group effect
positive or negative (1 or -1); then across groups use the same values
for similar regressors (1 1) and finally between use opposite values
(1 -1) - so say 1 for a given regressor in gp A and -1 for the same
regressor in gp B - this tells you that gp A has a positive
correlation and that this is significantly diff from the negative
correlation in group B (you can then plot this to see the regression
lines).
good lulck
cyril
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