[open] OpenSesame for fmri experiment, am I too risky?

Katerina

Hello,

because I am in favor of OpenSource software I decided to use OpenSesame to program an fmri experiment for my phd thesis. How many of you are out there, who would recommend that? Have you used it without problems? Timing is extremely important for this experiment because the events I am measuring are normally shorter than a TR.

I guess I'll be bothering you with questions in the future. Can't wait.

Thanks!

sebastiaan

Hi Katerina,

OpenSesame has certainly been used for fMRI research. As with all other software, you need to test your experiment carefully, but then you should be fine.

Timing should be no issue, particularly not if you send triggers to mark the timing of events. If you rely on 'absolute timing' (i.e. you don't keep track of when things occur, but just assume that trials last, say, exactly 5s), you will need to add a short script to the start of your trial_sequence, as described here.

Cheers!

Sebastiaan

elizabeth

I am in the same situation and quite nervous...but the idea of making all my tasks in Presentation is motivating me to try OpenSesame, which is such a pleasure to use.

Sebastiaan, when you say "...send triggers to mark the timing of events", how would I do this in OpenSesame? For analysis, I specify the onset (relative to the start of the EPI session which is 1 opensesame experiment) and duration for each stimulus event. This should be the same for all subjects of course.

sebastiaan

Sebastiaan, when you say "...send triggers to mark the timing of events", how would I do this in OpenSesame?

You can do this with a simple inline script, as described here:

• http://osdoc.cogsci.nl/devices/triggers/

Of course, the what and when of the triggers depends on the particulars of your experiment. Does that answer your question?

Cheers,
Sebastiaan

elizabeth

I will try this, although the trigger in my case is sent as a '5' through USB like a keyboard which I think is a bit different. In any case, I would like to try to rely on 'absolute timing', but am having some trouble getting this implemented. But will post in a new comment.

A_lice

Hello,

I would like to use the script mentionned above to mark the timing of each events of my fmri experiment. However, the link does not work. It's possible to refresh the link please ?

Thank you very much

Cheers,

Alice

eduard

Hi Alice,

I believe the link pointed to a previous version of this page here: https://osdoc.cogsci.nl/3.3/manual/devices/parallel/

But I think the inline_script that Sebastiaan mentioned there doesn't appear on the that page anymore.

What precisely is your goal? Depending on your experiment, these timings might even be logged automatically (if you only use sketchpad items, and such), if you have a more complicated experiment with inline_scripts, you might need to add some custom events yourself.

If you want the fMRI and behavioral to interact, things are a little trickier.

Eduard