Hi Alex,

The weighted parameter should be a single value that indicates if the contrast is weighted by the number of trials or not. If the value is 0, then the contrast is not weighted by the number of trials. If the value is non-zero, then events where all the duration's are less than the value, then those events are weighted by the number of events.

For the contrast, you want
P.Contrasts(1).left={'Con1' 'Cond4};
P.Contrasts(1).right={'Cond2' 'Cond3'};

The reason behind this due to how we rearrange the equation:
(Cond1 - Cond2) = (Cond3 - Cond4)

becomes

Cond1 + Cond4 = Cond3 + Cond2

when we eliminate the negatives to get the left and right sides.