Thanks Gang.

We want to simplify our model and only include 1 qvar, weight.

The model would then be: -model 'time*weight'

To investigate the investigate the effect of the interaction, we would compare the slopes for weight at each level of time, correct?

-gltlabel 1 'weight_ V1-V2' -gltcode 1 'Time: 1*V1 -1*V2 weight : '

-gltlabel 2 'weight_ V1-V3' -gltcode 2 'Time: 1*V1 -1*V3 weight : '

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If this is correct, a significant contrast for weight_V1 - V2 from the above glt would mean the effect of weight is more correlated with the imaging data at V1 than V2? Would that be correct?

Thanks.

Michael