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BTW, variability of 8 to 14 ms could reflect differing time to process
image (write to video memory). If images are same size (kb) this could
mean that your machine's video drivers and e-prime don't talk well. If
they are different sizes and driver communication IS ok, the larger
images should be those where delay is longest. You might need to check
your machine's suitability for visual stimulus presentation (nVidia
drivers sometimes show large slop .. if you have nVidia chip, try ATI
radeon card maybe, if this is the case).<br><br>
At 12:22 PM 15/04/2009, you wrote:<br>
<blockquote type=cite class=cite cite="">Dear David<br>
I have read Chapter 3 of
Userguide thoroughly, but still feel a little confusion. In each block of
my programme, there was a TextDisplay, a Inline Scripe and a
ImageDisplay(stimulous).To synchronize the signal of NeroScan and the
stimuli of e-Prime, I have inverted a in-line WritePort command before
"ImageDisplay" and set the PreRelease time (100ms) in the
TextDisplay. However, the unwanted delay or unsynchronization still
existed between the e-Prime and EEG recording system result in anormal
delay of N170 component. Thus, I want to ask whether the WritePort
command was sent to the recording system at the beginning of Prelease
time or at the point when stimulous presents on the screen. In other
word, I want to know whether the WritePort command and image were sent at
the same time from E-Prime.<br>
Thank you for your concerning.<br>
<br>
> Date: Wed, 8 Apr 2009 11:26:12 -0400<br>
> To: e-prime@googlegroups.com<br>
> From: mcfarla9@msu.edu<br>
> Subject: Re: Image display delay<br>
> <br>
> <br>
> At 4/5/2009 09:35 PM Sunday, maocong wrote:<br>
> >I am a greenhand in programming on e-prime, and I need some help
on<br>
> >the fellowing issue:<br>
> ><br>
> >I designed an ERP visual stimulous experiment by using the
control of<br>
> >ImageDisplay on e-Prime 2.0v and the EEG recording system is
NeroScan<br>
> >4.3v. And I found a 8~14ms delay on image display(shown by
the<br>
> >programme running result file), and the help file showed this
delay is<br>
> >the difference between orignial onset time and actual display
time.<br>
> >This random image display delay greatly effect the accuracy of
N170<br>
> >latency recorded, which lead to the unreliablity of the
experiment<br>
> >result. Therefore I hope you can give me some advices about how
to<br>
> >eliminate/compensate this display delay or how to uniform this
display<br>
> >delay<br>
> <br>
> Please read thoroughly chapter 3 ("Critical timing...") of
the User's <br>
> Guide that came with E-Prime.<br>
> <br>
> -- David McFarlane, Professional Faultfinder<br>
> <br>
> <br>
> More than mail–Windows Live™ goes way beyond your inbox.ox.
<a href="http://www.microsoft.com/windows/windowslive/">More than
messages</a><br>
</blockquote><br>
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