Dear Sir/Madam I want to know the position of x an y co-ordinate when SPM get data within mask Y= Y(:,Cm); (line number 625 SPM2 of spm_spm.m file). I means Cm voxels with corresponding co-ordinates X and Y because I want to know the position of neighbor voxels.So where and what I can put the code in SPM if I want to estimate beta,s according to x an y co-ordinate direction . Thanks in Advanced