MWS Bilateral Screen Flashing

Here’s a nifty little trick for using MWS for asymmetrical visual stimulation.

Launch two copies of Mind Workstation and, via Browse Samples, select Screen Flashing from Simulation Type Examples. Alter the beat frequency of each copy to suit your requirements

Start each copy and resize the flashing windows to narrow vertical strips (1-2cm wide, full height of the monitor) on the left and right hand sides of the screen.

Position yourself facing the centre of the screen so that the flashing bands are at the edges of peripheral vision and look straight ahead. This is ideal for setting up attention/focus/ADHD type sessions where the matter being studied is displayed between the flashing bands.

Note that the effect is different depending on how far into peripheral vision the stimulus lies. If it is within the usual right and left visual fields, activity will be seen, with the EEG, over the main visual cortex. If the stimulus is outside the usual visual field and well into the peripheral, then no corresponding signal will be found over the main visual cortex, but will be found (if you’re lucky) over one or more supplementary visual regions. The latter has the advantage that the main visual field is left flicker free for reading, etc.

The method as it stands, relying on manual startup of the two copies is suitable for simple sessions where synchronisation of the left and right stimulus isn’t required.

It would be nice to be able to have multiple screen display tracks, but alas, MWS is currently limited to one.

Cheers,
Craig

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Comments

  • Arthur  On June 21, 2013 at 8:16 pm

    Craig,

    First, thank you for sharing so much information on AVS. I am not the first one to claim that this blog is THE ultimate resource on AVS, but i still want to point that out.

    Now that i have praised this blog enough, i will proceed to my question 🙂

    “This is ideal for setting up attention/focus/ADHD type sessions where the matter being studied is displayed between the flashing bands.”

    Do you mean that for an ADHD person, placing a text being studied between flashing regions of the screen will enhance learning and save that person from distraction/chatter? Am i understanding the method correctly?

    What settings for each flashing screen would you start with?

    P.S. I remember you mentioning a software of your own making that creates two flashing screens. Is any beta version available? Would really like to try stimulating my brain visually and see if it helps with reading, since i am having a real hard time reading anything that is even remotely boring. Typical ADHD symptom.

    • CraigT  On June 23, 2013 at 10:19 am

      Hi Arthur,

      Pleased you’ve found the blog useful.

      Just use the standard MWS attention and focus sessions – listen to only one and use the screen flashing from both.

      The idea is to have the text you’re working with displayed between the two flashing strips. Does it work? No reason why it shouldn’t, but it’s just an idea.

      I did write a program but it fell by the wayside after proof-of-concept.

      Good luck with it and I hope you’ll share your results.

      Cheers,
      Craig

      • Arthur Galegov  On June 23, 2013 at 10:52 am

        Craig,

        Will try it right now and report back.

        What i did try is i started MWS, made the window with visuals full screen and on top of that window i dragged my reader’s window, so that flashing was only visible on the side of the screen. Of course, both flashing regions were working at the same frequency – they were a part of the same window.

        Those focus and attention sessions in MWS – do they have different light sequences programmed for both channels? I guess i’ll have to sit pretty close to the monitor in order for the visual signal to be delivered to an appropriate side.

      • CraigT  On June 23, 2013 at 1:23 pm

        Hi Arthur,

        That sounds like a perfectly fine approach. Some of the sessions use different left/right, but screen flashing doesn’t acknowledge that – if you want asymmetry you will need to run two copies with the beat rate on one copy tweaked.

        It’s all good fun – sometimes you even get useful results 🙂

        Cheers,
        Craig

      • Arthur Galegov  On June 24, 2013 at 1:45 am

        Hey Craig!

        Yeah, that sounds like a good idea.

        I run my NP3 copy on a VMware virtual machine, so performance becomes an issue when i start two copies and i think there are some frames that just drop off.

        I was thinking about capturing the video part of sessions with some sort of a screen-capture software and then mixing them down in Adobe Premier or similar software. This way i can just playback the video which should eat less resources.

        What kind of frame rate should i use, though? I know that screen-flashing in it self has its drawbacks which have to do with refresh rate of the display. Just don’t want to shot myself in the leg by limiting the session’s effects even further.

        I guess, in order to stay at least within the boundaries of my display performance, frame rate per second of a video file must be equal of a refresh rate of a display?

        Just thinking…

      • CraigT  On June 24, 2013 at 7:22 am

        Hi,

        You’ll need a frame rate of at least twice the desired flash rate. I have had little success capturing screen flashing – way too many dropped frames. Running in a virtual machine will make performance that much more of an issue.

        Cheers,
        Craig

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