Dear SPMers

Hi

I'm  trying to perform a first level GLM analysis on my task fmri data.After creating "SPM.mat" and estimating the betas I use Results tab to view my activated area.However,there is something called as "& extent threshold{voxels}" with a default value of zero (just below the T or P value).

I dont know what to fill in!As I leave the voxel threshold zero (considering a voxelwise study) I get  scattered activation areas.

Could you please tell me the proper value for a voxelwise study which I could get a compact area of activation?

 Regards

 Mahsa,