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Medical Inversion of human vision

  1. Mar 2, 2017 #1
    Mentor note: Split the thread in two parts, the other part is here: When (and Why) Does a Human Baby's Vision "Flip". This thread discusses the inversion of human vision, "up/down", "left/right" and 180 degree rotations.

    Greetings to all,
    I realize that there is another "dead thread" about this subject (with a lot of interesting comments) but I think I can add a "new dimension" to the conversation.:smile: I have also put this question out on a few other Science Forums....

    The human eye is much like the lens of a camera, telescope or microscope. An image, as it passes through the lens, is projected onto the retina upside down and backwards. It is the brain's job to sort out and make sense of the image entering through the eye.

    Teacherman
     
    Last edited by a moderator: Mar 3, 2017
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  3. Mar 2, 2017 #2

    mfb

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    Not relative to the body.
    If you are on the ISS and suddenly the image would be inverted, you would realize something is odd in the same way as you do on Earth.

    How did they test the perception of babies? You can see if they move their arm in the wrong direction, but directed motion of the arm takes some time to develop on its own.

    There are special glasses inverting the vision, tests with adults show that the brain manages to flip it back after a few days of training. Take the glasses off and the brain again needs some time to adapt.
    One report here
    More tests here
    You can even buy those inversion glasses if you want to test it yourself.
     
  4. Mar 2, 2017 #3
    Thanks for your response, mfb,
    Here is the video of the Erismann & Kohler experiments with inversion goggles in 1950. Unfortunately there is no sound and the captions are in German. But it is definitely worth watching to the end. Keep in mind that the glasses are made with mirrors. They invert the image but they do not flip it backwards.
    Teacherman
     
  5. Mar 2, 2017 #4

    BillTre

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    I have actually used some similar glasses in a physiological psych lab many years ago. The glasses I used merely offset rather than inverted the images going to the retina. At first it was pretty disorienting, but after 5-10 minutes of of playing around with a ball, I (and others) were able to throw and catch fairly accurately.

    It was an interesting experience and to me. It seems to me that it involved coordination between: relating retinal images and eyeball orientations and spatial orientation with respect the body as well as then relating that to the ability to properly coordinate body movements to suit those changes. If the mapping of the images to the space wrt the body was worked out, then the body movements should just follow along without requiring many changes.

    One's perception of the space around one's body involves the integration of senses other than just vision. Hearing also maps to that space. At least some of that combining of senses (in at least some amphibians) occurs in the optic tectum (a midbrain structure where visual information goes before getting to the cortex in humans). Orienting reflexes (such as turning toward load noises, to identify threat or whatever) involve the optic tectum.

    Changing how the visual information is arrayed in the midbrain would be one way to adapt to this situation, but would probably require regrowing optic axons which would take days at least. Alternatively just changing the controls on eyeball orientation (controlling the eyeball moving muscles (extra-ocular muscles)) could deal with it all fairly rapidly.

    Visual inversion, however would be a more drastic change, which would have to be dealt with differently. On the other hand, there is more than one flow of visual information through the brain and some streams might be more easily changed or more easily observed, particularly in poorly communicating babies.
     
  6. Mar 2, 2017 #5
    Thanks for your response, Bill
    Here is another way one could adapt to the problem of inverted vision...
     
  7. Mar 2, 2017 #6
    This video by Erismann & Kohler (1950 or so) demonstrates what happens when the images are reversed left to right. At least this video is narrated in English....
     
  8. Mar 2, 2017 #7

    BillTre

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    Type setters used to learn how to read inverted print they would set before the digital age.
    Similar to seeing ambulance printed backwards on the front of ambulances so people could read it in their rear view mirrors.
    This seems quite learnable to me.
     
  9. Mar 2, 2017 #8
    Surveyors also had to do it with transits - i believe right into the 60's.
    Of course, even today, anyone who uses a celestial telescope or microscope has to figure out how to move the instrument exactly opposite what the brain insists it has to do.
    Teachers learn to read upside down, too. It makes it easier to read those kids books with illustrations in "circle time" and to see how kids are doing as they move through the classroom.

    Thanks for your comments, Bill
    Teacherman
     
    Last edited: Mar 2, 2017
  10. Mar 2, 2017 #9
    How about just letting visually dyslexic kids do what comes natural.... and observe.
    There are a lot more of them to observe.


    ...and I believe strongly that this is not an "empty exercise".
     
  11. Mar 2, 2017 #10

    Andy Resnick

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    There was some work done with frogs and newts along this line, but I can't recall any specifics. I found this:
    http://www.tutis.ca/Senses/L2VisualCortex/FrogEye.pdf
    It mentions that the animals re-learned how to see 'correctly', but no specific details.
     
  12. Mar 2, 2017 #11

    BillTre

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    This article is early evidence for a chemical mechanism rather than a learning based mechanism underlying the topological projection of nerve fibers from the retinal (which can be considered a 2D sheet with dorsal-ventral and medial-lateral axes) to the optic tectum (amphibians don't have cortex). A similar pair of axes are thought to be present where the fibers are making contacts with the next set of neurons in the pathway. The chemoaffintiy hypothesis was one of Sperry's big things in his research, along with the split brain experiments (corpus callosum cuts). He got a Nobel prize.

    When this was published, I was 3 and there were not any good methods of labeling and tracing axons to find out in detail what was happening anatomically.
    Matching dosral-ventral gradients of molecules know to be involved in guiding growing axons to their proper targets have now been found in the retina and optic tectum as well as zebrafish mutants affecting the process.

    Here are some fun pictures of the axon projections to the optic tectum.
     
  13. Mar 2, 2017 #12
    Randy, I have a feeling that this article (that I have never seen before) Is HUGEly, HUMONGOUSLY, TREMENDOUSLY IMPORTANT to understanding what I have been researching for the last 10 years!! I've read it through once - but will have to do so a few more times to really fully grasp the ramifications of these findings.
    Thank you SO MUCH!!!
    Teacherman:smile::smile::smile:
     
  14. Mar 2, 2017 #13
    I just got done reading it through for the third time........
    WOW!
    IF (and that's a big if) this is true in humans it could turn the way we teach reading and writing on its head - literally.
    You made my day, Bill !
    I owe you one....
    Teacherman

    See the smile on this little girl's face. Multiply that by thousands......
     
  15. Mar 2, 2017 #14

    mfb

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    What I don't get about the inverted writing: Do they read normally and write inverted? If you just see everything inverted, you'll just learn the inverted letters (the shape of letters is arbitrary anyway, and right-to-left writing systems exist as well), but write them normally to have your writing matching what you see elsewhere. If you write opposite from what you read (so your own writing appears wrong), things get odd.
     
  16. Mar 2, 2017 #15
    The fact is that the eye has a lens that inverts an image. That's physics, right??

    "I always ask myself "what could be the possible evolutionary advantage in a baby 'seeing things' upside down?"

    I think you are asking the wrong question, Sophie.

    Shouldn't it be "what could be the possible evolutionary advantage in a baby 'seeing things' right-side-up (based on gravity)? And I would answer that when you live in the modern world, where up and down and left and right are crucial to everything we do (especially reading) then those who can "flip" their inverted vision at an early age have the advantage.

    Hence, visual dyslexics are screwed.....

    Teacherman
     
  17. Mar 2, 2017 #16
    Thanks for your question, MFB
    I think I will let this 74 year old dyslexic reading teacher explain what it was like for her....
     
  18. Mar 3, 2017 #17

    mfb

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    We split the original baby discussion out, it is now here. This thread is about vision in general, the topic most posts in the thread covered already.
     
  19. Mar 3, 2017 #18

    sophiecentaur

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    This 'fact' is always overstressed. How is it at all significant? The brain doesn't look at itself like a Design Engineer with a drawing board would do and it is very naive to think that it would. Would you also expect that, in the wiring of the nerves, the areas of the brain structure involved in visual perception that are nearer the top of your head would necessarily deal with information from the 'lower' areas of the retinal surface (or, for that matter, the 'upper' areas)? The very first time a newly born animal gets a visual and physical stimulus which it can associate together, the internal World model starts to associate physical events (touch, heat etc.) that occur in a certain direction with a particular area on the retina, the mapping between vision and other spatial information starts to form and, of course, we can expect much of this to be hard wired in the first place.
    In the old days of Polaroid Instant Pictures, did anyone ever stop to consider which way up the picture was, as it was peeled off the back of the camera? Of course not. The picture itself was instantly orientated correctly by the user because of the context of the content of the image. There were times when this 'upside downness' was a problem in everyday life. When you tried to load 35mm colour slides in a projector when the brain / picture interaction was not involved - you then either had to learn about the optics or rely on the spot that someone put on the top right of the slide. That is dealt with on an intellectual level and nothing to do with the internal workings of our vision.
     
  20. Mar 3, 2017 #19
    Sorry about the delay....
    Here's part 2 of the interview with Mary Frapier, retired reading teacher, who struggled with Inverted Vision most of her life......

     
    Last edited: Mar 3, 2017
  21. Mar 3, 2017 #20
    Thanks for your response , Sophie
    So let's back it up for a second. Forget the whole idea lens inversion and "flipping" of images .
    How would you explain this woman's dilemma? I am simply looking for an explanation of a phenomena that turns out to be very common - at least in my experience.

     
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