Hello

 

I am working with spm 8 and a 17 subject one group, 2 time(pre post) X 2 condition (on off) ANOVA for fmri data. I currently have an estimated model which has column 1 pre, column 2 post, column 3 on, column 4 off; then the 17 subjects complete the design matrix.

 

This is a new design for me; I am use to the design matrix displaying the subjects before the conditions. I have made several attempts as to get the subjects first in the design matrix and have been unable to do so.

 

I then moved on to make the contrast but since the model is arranged in a different format my contrast (ie: main effect of time) does not work.

 

Interestingly when I use the contrast for main effect of time as zeros(1,17) 1 1 -1 -1 it did in fact accept the contrast but the weight was listed at column 18; thus over the subjects not over the conditions and because of this I do not believe the contrast is showing the activations associated with the main effect of time.

 

Could someone please with some ANOVA experience in spm8 please help me understand why the subject are listed after the conditions; even though I entered the subjects as factor 1 and main effect 1 in the flexible factorial ANOVA.

 

And please help me to understand how to adjust the contrasts accordingly to match up with the model or is the contrast I used correct for the main effect of time.

 

thank you for any help with this matter.

 

Jef

 

 

 

Jeffrey West, M.A.
Research Analyst
Maryland Psychiatric Research Center
Baltimore, Maryland 21228-0247
Phone: 410-402-6018
email: [log in to unmask]