[Eeglablist] About stimulus presentation delay

[Pratik Chhatbar]

Just a thought - can you have a photodiode sensor stuck on the screen
itself to record the exact time of display? this way you will have an event
of exactly when the display was started. This would mean compromise of one
channel (or an extra channel), but now you would have the exact timestamp
of the presentation onset rather than working with average jitter and the
noise assumptions about the jitter. Best, Pratik

On Tue, Sep 20, 2016 at 9:39 PM, chao wang <hnchaowang at gmail.com> wrote:

> Hi, everyone,
>
> We're recording EEG data and we use E-Prime to present stimuli. During
> recording, stimuli are presented to subjects via a projector. The projector
> induces a delay between stimulus presentation on E-Prime computer and in
> front of subjects. We measured this delay and found that the delay was not
> constant across trials but instead jitters within certain range around the
> average. I would like to know is there a typical range of the jitter that
> can be accepted in ERP experiments? And in this situation, what should I do
> to segment EEG data with respect to stimulus onset? I mean, use the average
> delay to determine the real instant of stimulus presentation, or any other
> ways exist? Forgive me if my words is not clear :)
>
> Thank you in advance!
>
> Chao
>
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