[Freesurfer] Optseq with Sparse Sampling

Hi,

I'm planning to run an auditory experiment using a pseudo-sparse sampling design. Something like: 4 sec stim period + 2 sec acquisition + 4 sec stim period + 2 sec acquisition ...

So for example, I'd like to find an optimal sequence for a design with a TR of 6 seconds but where the stimulus presentations can only occur in specific 4 second intervals after acquisition. There is room for jittering either in which 4-sec periods are NULL or alternatively in which part of the 4 seconds is occupied by stimulus (e.g. 3 sec stim + 1 sec NULL).

Is there a way to use optseq for this type of design? For example, maybe you could specify when half of the NULL conditions occur.

Thanks, Sam Norman-Haignere