Paul - Thanks so much for your input. One thought I had yesterday (which you seem to have come up with too) was to generate a video that basically included the movie, still images and my targets (behavioral task to maintain attention). I would edit six frames to run and then maintain the non-moving images for a set but externally randomized intervals (take the ISI times, randomize in excel and then use that sequence in the editing of the still images). I would do the same for the targets. I would add a white box at the bottom of the screen when these various elements begin/end. Running the video off of a monitor and use a photo cell (under a tent) to record when these elements appear and then go back and sync the EGI recording to the photo cell indicators. This borrows from the eye tracking technique and bypasses EPrime. <br>
<br>I will take a look on the pst site. Yesterday I didn't get to test my duration theory to see if this is strictly a loading issue, instead I tried a few other approaches - unsuccessfully. Monday I will change durations to confirm a loading issue, which my gut tells me it is. If that is the case this will call for radical problem solving (like what I am thinking above) rather than figuring out how and where to customize the script.<br>
<br>Thank you for the StimMaker ellipse script. Will review in WORD and see on Monday if I can get it to run. <br><br>Thanks so much for your help. We may be wired to learn by trial and error but this process has been ridiculous, I have spent a very long time learning all the ways this can't be done.<br>
Best,<br>Lisa<br><br><br><br><div class="gmail_quote">On Thu, Aug 18, 2011 at 7:04 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>
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>
<div><div></div><div class="h5">> 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 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 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>> wrote:<br>
>><br>
>> Lisa,<br>
>><br>
>> OK, I will ask the obvious dumb question. If you already have a program<br>
>> that works in Presentation, why would you want to recreate it in E-Prime?<br>
>> Although in principle E-Prime should be able to handle this, it may 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 original<br>
>>> experiment used that software’s programming language to create a color and<br>
>>> motion stimulus that allowed the researchers to compare the 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. While<br>
>>> I am not able to control luminance it appears very close to the original.<br>
>>> The motion stim is proving much more complicated. I created a vertically<br>
>>> oriented sinusoidal spatial frequency grating as an animation file in Final<br>
>>> Cut (editing software) and have been struggling ever since to make it work<br>
>>> as intended.<br>
>>><br>
>>> The experiment calls for a low frequency grating to traverse from left 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 be<br>
>>> able to use the video start/stop feature; additionally, randomizing 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 animation<br>
>>> that means that I have 10 six frame sets per second (each set 100ms). 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 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 frame of<br>
>>> each set and then finished the sequence with my one remaining frame (5 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 are<br>
>>> not similar in size, so I have an inconsistency there – issue one. The other<br>
>>> issue is that the two images (movie/still) overlap rather than following in<br>
>>> sequence. One appears inside the other and the error message I get once I<br>
>>> abort is “unable to update frame.” I did eliminate the 500ms ISI but that<br>
>>> has not helped. I also tried to eliminated the jpeg files but then I can<br>
>>> only randomize the duration of the motion which should be consistent at<br>
>>> 100ms intervals. It is the time between presentations that should randomly<br>
>>> fall within 500 to 100ms.<br>
>>><br>
>>> I am at a complete loss as to what to try next. HELP!<br>
>><br>
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