It tries a bunch of random orders until it finds one that is optimum in terms of efficiency (you can also specifically optimize with respect to counter balancing, use the --focb switch; I usually choose 100 for n). With jittering (instead of a fixed ISI), you get more temporal randomization (ie, differential overlap between adjacent events).
Hello all,
I'm a new user of Optseq2, and I have 2 questions about optseq2 after I got some sequences and read Dale (1999).
I'll be grateful to anyone can provide help.
1. I'm curious about why optseq2 arranged the order of conditions, does anyone can provided some references to me?
Dale (1999) just discussed about mean ISI and fixed/randomizes ISI design, I wonder what's the difference if I just keep the duration order of null condition (jitter) and randomly present different conditions.
I'm not sure what you mean. How can it be a delay if it is after the trial is over?
2. This question is about the total duration of experiments. I'm used to execute experiments by E-Prime 2.0, and the presentation may delay in E-Prime (I know this situation can be deal with "Pre-release"). If there's a fixation period (15s) after my trials is over (but participants are still scanned), and the delay just affect the duration of the fixation period. Should I reduce the duration of delayed stimulus in terms of the delayed time? Or I don't need to care about the delay, because the key point is the order of conditions and null/jitter?
Thanks for your reading.
Best regards,
Chih-Hao
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