Go/No Go Task Timing and Accuracy Logging

[Nick]

Hi Katherine,

If I understood correctly this would be my solution:

instead of using ACC you could just use RESP and use this to save
their accuracy.

Dim CorrectReject as Integer

IF StimSlide2.RESP = "" then
CorrectReject = 1
sleep (1300)
else
CorrectReject = 0
End if

c.SetAttrib "CorrectReject", CorrectReject

I use an inline currently on a go/no-go to make the analysis quicker.
So would also place a variable like EOC into the same script.

Hopefully this will help.

Regards,

Nick






On Apr 29, 6:39 pm, katherine <katherinekoe... at sbcglobal.net> wrote:
> Hello Everyone,
>
> I would be very grateful if you could help me with a task I am
> programming. I am having a problem with a Stop Signal (Go-NoGo) Task.
>
> This task has two conditions - Go (with two stimuli: < and >) and No
> Go (Stop Trial) (also with stimuli: < and >). Each trial is timed to a
> trigger from our scanner, which comes every 2.8 seconds. Each trial
> lasts for two trigger periods (5.6 seconds). The Go condition is
> working fine. The subject sees a "ready" crosshair for 500ms, then has
> 900ms to respond to a stimulus prior to a feedback slide. In the Stop
> condition the subject sees a "ready" crosshair for 500ms, sees a
> stimulus, and hears a beep ("sound delay") shortly after the
> presentation of the stimulus, which cues them to inhibit their
> response. The timing of the presentation of the beep is dependent upon
> a staircase. As the accuracy of the subject's responses on the Stop
> Trials increases the time between the presentation of the stimuli and
> beep should also increase. As accuracy decreases, the time should also
> decrease. The goal is to keep the subject's accuracy around 50%. At
> the beginning of the task the experimenter enters the starting time of
> the beep presentation, based on the ending time from the subjects
> practice run (hopefully already close to 50%).
>
> I am having two problems with the script as it currently stands.
> First, I am trying to set up the No Go portion (Stop Trial) of the
> task so that it lasts for two trigger periods. Currently, if a subject
> mistakenly responds on a No Go trial the "TrialBlankEnd2" display is
> skipped. "TrialBlankEnd2" is a blank 1200ms display which is used to
> lengthen the duration of the trial in order to ensure the trial lasts
> for two trigger periods. If ""  is skipped the next trial starts after
> only one trigger period.
>
> I tried to achieve the same effct by using a "sleep" command, using
> the following code:
>
> c.SetAttrib "StimSlide2.ACC", StimSlide2.ACC
> If StimSlide2.ACC = 0 Then
> sleep (1300)
> End If
>
> I tried to insert this code in an inline file after "sound delay," but
> it seems that when this code is implemented StimSlide2.ACC is always
> set to zero, instead of set to 1 (which it should be set to when the
> person correctly inhibits) The result is that the staircases I've set
> up do not work.
>
> What I'm looking for is a way to ensure that no matter what the
> subject's response on a Stop Trial, the next trial does not start
> until two trigger periods have elasped (5.6sec). If "TrialBlankEnd2"
> is skipped, the next trial starts after one trigger period (2.8sec).
> If I use a sleep command, it seems to throw off the accuracy count (on
> which the staircasing is dependent).
>
> It seems as though the script is set up correctly for the most part.
> The staircases do work when the accuracy count works. Is there a
> better way to set up The Stop trials that will ensure that the trials
> have "blank time" on the end and that the accuracy counts are
> accurate?
>
> Thank you very much for your help with this. I appreciate it.
>
> Katherine Koenig
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