Missing task events Chronos
Hi,
I'm using Eprime 3 with Chronos and an adapter for ANT neuro eeg stations in order to record triggers in the EEG signal. After several tests I find that some triggers are missing in my signal.
I'm working on a Simon task and tried a simple case where I want a trigger to be sent at each stimulus onset.The ultimate goal is to get a stimulus specific trigger (there are 4 exp. conditions) and a response specific one (correct or not) for each trial.
Since I was having trouble having stimulus specific triggers (numbers did not correspond or triggers failed to appear in some trials for some reason), I tried a simple case by just sending a timestamp at each stimulus onset regardless of condition:
After running the experiment 5 times, I find that some of the triggers are missing, and not always by the same amount (53 instead of 60, or 48 instead of 60, or 46, etc...).
I'm not sure where the problem comes from. I tested on another eeg station (and with other parallel cables) which I'm sure works well because used routinely in other projects. Same problem.
Am I doing something wrong or is it possible that I have a hardware problem either with my Chronos box or with the ANT neuro chronos adapter, or the chronos usb cable?
Thanks a lot for your help.
Best,
Joan
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You might find more help at the E-Prime Google Group, groups.google.com/group/e-prime.
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Hi François,
After much investigation, it looks like my problem comes from the ANT system. I tried the exact same task with two different other systems (EGI, Labchart) and it works just fine. So far ANT hasn't figured out where the problem originates but apparently it would have to do with the cascading wiring of their amps (we have a 256 cap so 4 amps wired together). Does your problem also occur with an ANT system ?
Cheers,
Joan
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