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different timing btw event codes and beh variable

Posted by silvia bernardi 
different timing btw event codes and beh variable
December 01, 2019 05:27PM
Hi Jaewon,

I have a quick question. This is my input:

trial_start=run_scene(scene0,25);
bhv_variable('START', trial_start);

I obtain a bhv_variable that is 0.2 msec earlier than the event code 25. Why is that? is it because the event code encodes the timing the scene is drawn while the behavioral variable encodes the exact start?

Silvia
Re: different timing btw event codes and beh variable
December 02, 2019 03:46PM
I don't understand what you mean by "the exact start".

They both indicate the same event, screen flipping, but the timestamp of the eventmarker is acquired when the Strobe Bit actually goes HIGH, which is 125 us after, by default. That delay is necessary to allow some time for digital output lines of Behavioral Codes to be stabilized.
https://monkeylogic.nimh.nih.gov/docs_MainMenu.html#Strobe

The National Institute of Mental Health (NIMH) is part of the National Institutes of Health (NIH), a component of the U.S. Department of Health and Human Services.