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Jakob
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Audio files not playing in fMRI paradigm, Posted November 24th, 2014 #1
Hi,

So I made this behemoth of a thing to present visual and auditory versions of the n-back task in an fMRI setting. The test alternates between showing single letters on the screen with playing audio files with a recorded voice saying the letters. Presentations are 4-16 letters long of either visual or auditory stimuli and the task is either 0- or 2-back. Every 4th letter the test waits for trigger.

The problem is: a couple of minutes into the test Superlab stops playing the audio. The test moves along as it should, switching backgrounds to indicate task, presenting visual letters when it should, but the audio is gone. This does not happen when simulating the trigger by pressing a key on the keyboard.

I will stop here certain that you need more information but are in no need of a wall of text. So please, any ideas? What information would you like me to provide?

Thank you,
Jakob
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Hisham
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Posted November 24th, 2014 #2
I’ll certainly need more information. Can you post the experiment, or if it’s too large, post a link to it?
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Jakob
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Posted November 25th, 2014 #3
n-Back

.rar-file
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Jakob
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Posted November 25th, 2014 #4
Some additional information:
What we have been trying to do is run Trial1 to make sure that everything works as intended. After the event "Wait for trigger81" the audio stops working but the test moves along as intended, switching backgrounds, displaying letters for the parts with visual stimuli etc.

Also: 4 stimuli + interstimulus intervals are 11.048s and we have set the scanner to 11.148s intervals.
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Jakob
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Posted November 27th, 2014 #5
Experiment pack version
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Jakob
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Follow-up for anyone interested, Posted December 17th, 2014 #6
Did some investigating on my own and came to the conclusion that Superlab 4.5 stops playing audio after the 16th audio file (on my computer setup). On the recently installed 5.0 version on the other hand, the problem is gone and the software manages to play most of the audio files (although intermittently one or two files are not played).

Would still be interested in hearing of others experiences on the issue.
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Hisham
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Posted December 18th, 2014 #7
In looking at your experiment, it looks like it is not structured correctly. You have only three trials, each containing over 600 events. You’d want to have a lot more trials and a lot less events. SuperLab would then be able to manage RAM memory better, and you can also benefit from being able to randomize the trials if you want.

I encourage to try and use the stimulus lists feature if you can. If you haven’t done so already, please work through the “Getting Started with SuperLab” chapter in the SuperLab 5 manual. You will find it well worth the time.
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