[visionegg] Re: upper frame rate limit for random dot motiondisplays and gratings

Anne-Kathrin,

VisionEgg can 'easily' do this: Andrew has put some demos up on the web site (take a look at the Multistimulus demo as an example, , which does this simultaneously with double somersaults: You can see a screenshot and download a Quicktime movie which shows it working (obviously at low frame rate) without even installing the software: http://www.visionegg.org/screenshots.html

You don't need a special graphics card to do 200Hz: The latest nVidia drivers let you override the default refresh rate to 200Hz (or more if your monitor will support it). Pretty well any current nVidia graphics card intended for computer gamers and priced in the US$300-400 would be all that you would need - many high-end PCs come with a suitable card already. We just bought a Leadtek FX5950 Ultra (i.e. the nVidia FX5950 chipset) which is superb and has 256Mb of texture memory, for just $700 (Australian Dollars).

We know of two consumer-level monitors that are capable of 200Hz (for just a few hundred dollars): one is the LG Electronics Flatron 915FT+ (which may now be a discontinued model). The second is the (22 inch screen!) Iiyama CRT VM pro514 - available in the UK for rrp of 379 pounds (see http://www.iiyama.co.uk/) and thus presumably available in Germany. We haven't tried the Iiyama but it has very good horizontal bandwidth (142 kHz) - enough to do 800x600 pixels at 200Hz. We have two LG flatrons and they are fine, but only do 640x480 at 200Hz. One of these, in main electrophysiology setup, runs the VisionEgg with much more challenging stimuli than you describe, on a fairly old Athlon computer under Windows 2000, and goes for days at a time without dropping a frame.

Which is all to say 3 cheers to Andrew for his hard work in producing a system which really can deliver research quality stimuli for next to no cost!

David



Hi,
we need a visual stimulation device that can reliably present motion stimuli (random dot and gratings superimposed by noise) above 200Hz. Does Vision Egg support such an application? Are there special graphics cards and monitors that have been used for similar purposes preferably based on Windows as operating system?
Thanks for your help!
Best wishes A.-K. Warzecha

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PD Dr. Anne-Kathrin Warzecha
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        Department of Neurobiology
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David C. O'Carroll
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The University of Adelaide
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