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aboharbf

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Reply with quote  #1 
I'm looking for a way to time stamp times when a subject leaves or enters fixation, much like the Timer demo and the LBC fMRI task, but neither seems to be particularly flexible. What is the best route to create this kind of task?
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Jaewon

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Reply with quote  #2 
See if OnOffMarker suits your purpose.
ftp://helix.nih.gov/lsn/monkeylogic/ML2_doc/runtimefunctions.html#OnOffMarker

Note that OnOffMarker sends out eventcodes at the beginning of the next frame when fixation is acquired or broken, because behavior is checked at the same rate as the screen refresh rate in the scene framework. But you can retrieve the exact time with no problem.
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aboharbf

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Reply with quote  #3 
The exact time would then be saved where? I'd likely have the eventmarkers sent with a code to the Blackrock machine, but additionally perhaps I can make a photodiode conditional on this Adapter to get more exact times without the worrying about aligning clocks between machines.
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Jaewon

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Reply with quote  #4 
You can store the time in the property of an adapter (you will probably need to make your own adapter for this) and then save to the data file with bhv_variable.

Sending eventmarkers as soon as fixation acquisition or break occurs (within 1-2 ms) is simply not possible in the scene framework, as explained in the manual. You can use toggleobject and eyejoytrack to mimic the behavior or analyze fixation offline. The online detected fixation is an arbitrary measure anyway, because it differs depending on the size of the fixation window you set. If you are serious about the fixation timing, you should use eye velocity to determine the fixation.

All these are already explained in the manual. Please read it through.
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