Send Response Triggers to EEG (BrainVision)

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Maria Eugenia De Lahoz Naveiro

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May 26, 2021, 12:34:47 PMMay 26
to E-Prime
Hi David,

My experiment is an S1-S2 where S2 can have various types of stimuli with various responses. In the e-Prime design in the "DesignList" I have coded the different trials and the TrialProc. In there I created an attribute called "Response", in which I indicated what type of response is going to be associated with the different S2.
Then in the timeline created as "TrialProc" when placing the e-Objects that make up the different trials, the one corresponding to S2 has the Input Mask, encoded in properties, indicating that it is the keyboard and that the response is that of the attribute "Response". 

My question is, It is possible to send response triggers, whit an in line, when subjects respond and press the computer key. At the same form to send the triggers of stimuli S1 and S2

If this is so, it would be in the same in line where the trigger stimulus or a different, one placed before or after the  e-object that has the inputmask encoded. 


Attached my experiment structure, design list, Input Mask Properties/Encoded and in line stimulus trigger


Thanks For Your Help
Mariu
Triggers2.JPG
Triggers1.JPG
InputMaskEncoded.JPG
DesingList.JPG

David McFarlane

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Sep 17, 2021, 12:00:41 PMSep 17
to e-p...@googlegroups.com
Mariu,

Well it has taken me a long time to get to this (note that this is an
extension of the thread at
groups.google.com/g/e-prime/c/TRX15lgIStg/m/YQCQrME7BwAJ ).

I would try using Task Events to output a signal/trigger/marker at the
time of a response. Suppose you use a ParallelPort device to output to
your EEG, and suppose you use a Keyboard input mask for the response to
your stimulus EmojiS2. Then you could add Task Events tied to
EmojiS2.Keyboard(1).Press or .Correct or whatever.

Note that, as explained in several other threads here, when outputting
signals to an external device you should always do that in pairs, first
outputting the signal value, and then, after some suitable delay,
resetting the output to zero to prepare for the next
signal/trigger/marker. You may do that by adding two Task Events for
the same event, the first with delay of 0 to output the desired signal
value, and the second with some suitable delay (say, 20 ms) to output 0.

As an added precaution, you should also set the signal output to zero at
the start of each session, because you never know what state your
computer was in before the session started. You may do that with an
InLine, e.g.,

ParallelPort.WriteByte 0

-- David McFarlane
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