Thanks Paul - very helpful.<br><br><div class="gmail_quote">On Wed, Aug 24, 2011 at 3:20 PM, Paul Groot <span dir="ltr"><<a href="mailto:pfc.groot@gmail.com">pfc.groot@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Lisa,<br>
<br>
If you enter a numeric (hard coded) value into the duration properties<br>
of the wait1 to wait5 objects, you will indeed get fixed<br>
(non-randomized) intervals. Setting the ordering property of the list<br>
to random has no effect on this. There are several ways to get random<br>
duration values. The easiest way (=without any inline script) is to<br>
create a separate list and add an attribute with the interval values<br>
you would like to use. Set the ordering of this list to random (with<br>
or w/o replacement) and use this list as nested list in your real<br>
trial list. The name of the attribute (i.e. 'FootageInterval') can<br>
then be used to set the duration property in the wait objects. To make<br>
sure EPrime picks a new value from the nested list for each wait<br>
object you will have to use the following syntax for the durations:<br>
<br>
[FootageInterval:0] (for duration Wait1)<br>
[FootageInterval:1] (for duration Wait2)<br>
etc.<br>
<br>
Alternatively you could use a simple inline script at the start of the<br>
trial and use the E-Basic random() function to set durations. (That<br>
would be uniform random w/o replacement.)<br>
<br>
Hope this helps<br>
Paul<br>
<br>
<br>
2011/8/24 Lisa Levinson <<a href="mailto:lml1934@gmail.com">lml1934@gmail.com</a>>:<br>
<div><div></div><div class="h5">> Paul-<br>
><br>
> I have worked out a script that seems to run properly. Rather than use a<br>
> still/jpeg file between motion files I added a "wait" slide. So, my gradient<br>
> runs for 100ms and the wait slide follows allowing me to present a<br>
> non-moving image of the gradient for a specified duration. Note: in order<br>
> for the animation to run as a loop I have five motion files, loaded in<br>
> sequence. Here is my next challenge...I need five wait slides between my<br>
> motion files but I would like to randomly assign a duration to those wait<br>
> slides. At the moment I have them set up so that wait1 runs for 1000ms,<br>
> wait2 for 600ms, wait3 for 700ms, wait4 for 800ms and wait5 for 900ms. This<br>
> list is set for random but I am not exactly sure what I am getting. Do you<br>
> think wait1 will always run at 1000ms, wait 2 for 600ms, etc?<br>
><br>
> Lisa<br>
><br>
> On Thu, Aug 18, 2011 at 7:04 PM, Paul Groot <<a href="mailto:pfc.groot@gmail.com">pfc.groot@gmail.com</a>> wrote:<br>
>><br>
>> Hi Lisa,<br>
>><br>
>> It looks like this 'hybrid' movie/still solution is causing more<br>
>> problems than it solves. Like Presentation, you probably would like to<br>
>> use some script to create/present the graphics. Unfortunately, E-Basic<br>
>> only has limited support for creating graphics on the fly (text,<br>
>> lines, rectangles and ellipses), and I'm not sure if your stimuli<br>
>> could be drawn by those primitives. However, pre-created static<br>
>> bitmaps (as movies) can be a workaround for painting more complex<br>
>> graphics objects. Programming moving objects is not extremely<br>
>> difficult, and if I remember correctly, there is an example available<br>
>> on the pst support site<br>
>> (<a href="http://www.pstnet.com/support/samples.asp?Mode=View&SampleID=8" target="_blank">http://www.pstnet.com/support/samples.asp?Mode=View&SampleID=8</a>) When<br>
>> the graphics objects themself change, you might run into difficulties<br>
>> when the computer hardware cannot keep up with the number of required<br>
>> bitmaps and desired frame rate. Using movies will probably the only<br>
>> working solution in that case. I think I would include the ISI's in<br>
>> the movie so it becomes a single file that can be played without<br>
>> interruption. ISI durations cannot be set at runtime this way, unless<br>
>> you use the technique described below.<br>
>><br>
>> In some cases is also possible to use an external (DLL) library to<br>
>> create complex stimuli at run time (gabor patches, gradient fills,<br>
>> ...). Such an external library could be used to create bitmaps or<br>
>> movies on the fly, which then can be loaded by eprime. However, this<br>
>> requires in-depth knowledge of a programming language such as C++<br>
>> because such a specific library probably doesn't exist yet. I used<br>
>> this technique before to create audio files and complex bitmap<br>
>> sequences. (If you have EPrime version 1, you might have a look at the<br>
>> attached example. This will display a changing ellipse with a gradient<br>
>> fill that can be defined at runtime in EPrime)<br>
>><br>
>> Best,<br>
>> Paul<br>
>><br>
>> 2011/8/18 Lisa Levinson <<a href="mailto:lml1934@gmail.com">lml1934@gmail.com</a>>:<br>
>> > Yes, Presentation is better for this type of experiment, however, the<br>
>> > Presentation script was generated in a different lab and the lab I am<br>
>> > working in is not set up to use Presentation (requires a serial port<br>
>> > connection for which we have had issues with timing). So, you are 100%<br>
>> > correct, I have been jumping through complicated hoops for more time<br>
>> > than I<br>
>> > will admit and while I have made progress the motion stim for this<br>
>> > experiment is just crazy difficult to figure out. Today I was going to<br>
>> > attempt to increase the duration of stimulus presentation to see if it<br>
>> > is a<br>
>> > loading issue. Will let you know but any thoughts would be greatly<br>
>> > appreciated.<br>
>> ><br>
>> ><br>
>> > On Thu, Aug 18, 2011 at 1:26 PM, David McFarlane <<a href="mailto:mcfarla9@msu.edu">mcfarla9@msu.edu</a>><br>
>> > wrote:<br>
>> >><br>
>> >> Lisa,<br>
>> >><br>
>> >> OK, I will ask the obvious dumb question. If you already have a<br>
>> >> program<br>
>> >> that works in Presentation, why would you want to recreate it in<br>
>> >> E-Prime?<br>
>> >> Although in principle E-Prime should be able to handle this, it may<br>
>> >> require<br>
>> >> jumping through a lot of complicated hoops, and it seems to me that<br>
>> >> Presentation makes a better platform for this type of task.<br>
>> >><br>
>> >> -- David McFarlane, Professional Faultfinder<br>
>> >><br>
>> >><br>
>> >> At 8/16/2011 11:24 PM Tuesday, you wrote:<br>
>> >>><br>
>> >>> I am looking to replicate an experiment originally created in<br>
>> >>> Presentation for use with EPrime, part of an EEG experiment. The<br>
>> >>> original<br>
>> >>> experiment used that software’s programming language to create a color<br>
>> >>> and<br>
>> >>> motion stimulus that allowed the researchers to compare the<br>
>> >>> parvocellular<br>
>> >>> and magnocellular visual pathways. I do not know EBasic and so I have<br>
>> >>> created the color stim in Photoshop and imported the image as a slide.<br>
>> >>> While<br>
>> >>> I am not able to control luminance it appears very close to the<br>
>> >>> original.<br>
>> >>> The motion stim is proving much more complicated. I created a<br>
>> >>> vertically<br>
>> >>> oriented sinusoidal spatial frequency grating as an animation file in<br>
>> >>> Final<br>
>> >>> Cut (editing software) and have been struggling ever since to make it<br>
>> >>> work<br>
>> >>> as intended.<br>
>> >>><br>
>> >>> The experiment calls for a low frequency grating to traverse from left<br>
>> >>> to<br>
>> >>> right for 100ms with inter-stimulus intervals anywhere from 500 ms to<br>
>> >>> 1000ms. Because the stimulus presentation is so short I don’t seem to<br>
>> >>> be<br>
>> >>> able to use the video start/stop feature; additionally, randomizing<br>
>> >>> the ISI<br>
>> >>> is not possible using this feature. I determined that one cycle of the<br>
>> >>> animation sequence is 31 frames and with a 60 frame per second<br>
>> >>> animation<br>
>> >>> that means that I have 10 six frame sets per second (each set 100ms).<br>
>> >>> I then<br>
>> >>> created 6 frame .avi files and loaded them sequentially. Because the<br>
>> >>> experiment calls for 320 trials I had the choice to load 320 files or<br>
>> >>> create<br>
>> >>> a loop with 5 six frame sets, I opted for the loop. To allow for the<br>
>> >>> randomized ISI intervals I created jpeg files containing the final<br>
>> >>> frame of<br>
>> >>> each set and then finished the sequence with my one remaining frame (5<br>
>> >>> six<br>
>> >>> frame sets plus one final still, making 31 frames).<br>
>> >>><br>
>> >>> After loading the movie/still files (sequentially) it seems that even<br>
>> >>> though the stills(jpegs) were captured from the animation frames they<br>
>> >>> are<br>
>> >>> not similar in size, so I have an inconsistency there – issue one. The<br>
>> >>> other<br>
>> >>> issue is that the two images (movie/still) overlap rather than<br>
>> >>> following in<br>
>> >>> sequence. One appears inside the other and the error message I get<br>
>> >>> once I<br>
>> >>> abort is “unable to update frame.” I did eliminate the 500ms ISI but<br>
>> >>> that<br>
>> >>> has not helped. I also tried to eliminated the jpeg files but then I<br>
>> >>> can<br>
>> >>> only randomize the duration of the motion which should be consistent<br>
>> >>> at<br>
>> >>> 100ms intervals. It is the time between presentations that should<br>
>> >>> randomly<br>
>> >>> fall within 500 to 100ms.<br>
>> >>><br>
>> >>> I am at a complete loss as to what to try next. HELP!<br>
>> >><br>
>> >> --<br>
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