Hi all,
I'm conducting a multiple regression study on a population of subjects. The aim of the study is to find a correlation between the GM density maps and some neuro-psycological scores. To do this I've used the toolbox "vbm8" to segment the images and the multiple regression analysis of spm. For the normalization step I used Dartel. I intentionally removed the modultaion step because the images segmented with modulation were hyper-intense in the subcortical regions. Without modulation the GM images seem to be right. After the segmentation step I've applied a smoothing kernel of 10x10x10. For the multiple regression analysis I introduced the psycological scores as covariates and the smoothed GM maps as volumes. In the statistical phase I used the number of t-tests corresponding to the number of covariates. For example, if the covariates are 3 I used 3 t-tests with the following contrasts: [1 0 0], [0 1 0], [0 0 1].
Could anyone please tell me if I used the right procedure?
Thank you very much
Domenico
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