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My study involves 3 runs per subject -- I wanted to do Rand FX so I started by creating a multi-session (3 runs) fixed effect design for each subject -- there are 4 trial types which repeat in a counterbalance order across runs --- MY QUESTION IS ..... WHEN DEFINING THE CONTRAST (LETS SAY ALL-REST SO: 1 1 1 1) DO I NEED TO REPEAT THE FOUR ONES TWO MORE TIMES FOR ADDITIONAL RUNS OR DOES THE PROGRAM AUTOMATICALLY ASSUME THAT'S WHAT I WANT ---- SO DO I PUT 1 1 1 1 (THE DESING MATRIX GRAPHICALLY REPRESENTS EACH RUN/SESSION - BUT IF I ONLY PUT 4 'ONES' AND SUBMIT -- THE CONTRAST SEEM TO ONLY APPLY TO THE FIRST SESSION???) SO SHOULD I INSTEAD DO IT THIS WAY? 1 1 1 1 1 1 1 1 1 1 1 1 NOTE: I TRIED IT BOTH WAYS - MY DEGREES ARE FREEDOM END UP THE SAME - BUT I GET A LOT MORE SIGNAL WITH THE 12 'ONES' --- ?????? THANKS IN ADVANCE FOR ANY HELP IN CLEARING THIS UP --- SIGI