Hi Steve, the PSD window is the assumed length of the hemodynamic response and mostly unrelated to the timing of you paradigm. You need to control the duration (part of --ev), and --tnullmin and --tnullmax. I think that will get you where you need to be.
doug
On 08/12/2013 10:21 AM, Lukito, Steve wrote:
Hi there,
Please ignore my earlier question. The Cygwin is still a mystery to me but I have managed to run the optseq2 on a UNIX computer.
It seems there is no way to input jittered ITI and null trials at the same time in optseq2, is this right? This is because null trials by definition is equal to jitter (this is how I understand Douglas Greve’s slides). Unfortunately, I would like to replicate an experiment with three experimental conditions with four types of trials (=the exp conditions plus null trials). Each trial is jittered so that its length is between 2850 and 3350 ms long, which include the 1000 ms stimulus presentation.
My thought is to use psdwin=0 - 1850 ms (2850 ms minus 1000 ms stim presentation) for now and then later on replace this constant time window with the jittered ones (randomized). I assume that if I can build an optimum sequence for the shorter boundary of the ITI, they will still be as optimum when I replace the post-stimulus time window with the jittered one provided that the jittered time interval is of longer span. I am not sure if this is even remotely true so I would really appreciate anyone’s comment on this.
Best,
Steve
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