For sequence optimization, you may also check Wager's Genetic
Algorithm - version 1.1.2
http://www.columbia.edu/cu/psychology/tor/genetic_algorithms.html
On Wed, Mar 31, 2010 at 4:24 PM, Mark Woolrich
<[log in to unmask]> wrote:
> There is no straightforward answer to this sort of experimental design
> question. The answer will depend on what questions (contrasts) you
> want to be able to ask of the data - you can use tools like the
> design efficiency tool in FEAT to help you decide if what you are
> using as a design is sensible:
> http://www.fmrib.ox.ac.uk/fsl/feat5/detail.html#misc
> and use tools like optseq to optimise selected ISIs.
> http://surfer.nmr.mgh.harvard.edu/optseq/
>
> As a general guideline, I think people often do this kind of
> experiment with randomised ISIs (just for example: mean_isi=6,
> min_isi=3s, isis=max(gamrnd(mean_isi,1,num_isi,1),min_isi) ) so that
> they can more efficiently space trials in time, at the same time as
> allowing for the unravelling of the overlapping BOLD responses from
> consecutive trials.
>
> Cheers, Mark W.
> ****************************************************
> Dr Mark Woolrich.
> Tel: (+44)1865-283827 (OHBA)
> (+44)1865-222782 (FMRIB Centre)
> http://www.fmrib.ox.ac.uk/~woolrich
> ****************************************************
>
>
>
>
>
>
> On 31 Mar 2010, at 06:17, Patrick Thompson wrote:
>
> Dear all,
> I am working on a decision making task in which individuals have to make YES
> or NO response depending on nature of the stimuli. The stimuli should be
> displayed for at least 6 s to provide subjects with enough time to make
> decision on the nature of the stimuli. I only have one type of visual
> stimuli with yes or no answer associated with it. My question are:
> 1) Should I design this as a rapid event related design or fixed ISI design.
> 2) If designed as a rapid event related design what should the optimal ISI
> be.
> Regards,
> Pat
>
--
Best Regards
Xue, Feng Phd. candidate
Major in Developmental Cognitive Neuroscience
National Key Laboratory of Cognitive Neuroscience and Learning
Beijing Normal University
Beijing, China. 100875
Tel: +86-13810154455
web: http://psychbrain.bnu.edu.cn
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