I tried to run glm_fit to fit group membership. For this model, I have 3 diagnostic groups namely, HC, MCI, AD, and added lobar (Frontal, Parietal, Occipital, Temporal) WMH as the covariates. 

My contrasts are as follow: 

Group membership: 1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0; 0 1 -1 0 0 0 0 0 0 0 0 0 0 0 0

Frontal/Parietal/Occipital/Temporal MCI_HC: 0 0 0 -1 1 0 0 0 0 0 0 0 0 0 0 

Frontal/Parietal/Occipital/Temporal MCI_AD: 0 0 0 -1 1 0 0 0 0 0 0 0 0 0 0

Frontal/Parietal/Occipital/Temporal AD_HC: 0 0 0 -1 0 1 0 0 0 0 0 0 0 0 0

However, I got the error message that matlab element type is not a matrix and another error that it cannot allocate memory. Attached the error log and the command for your reference. 

I am not sure what went wrong, any help will be great. 

Many thanks, 

Heidi