Society & Culture0 min ago
Upside-down eyeballs
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If a person's eye were taken out and then put back in upside down, would the person see upside-down? (Asked by my seven-year-old son.)
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Hmmm
The image that forms on the retina is upside down as it is. The brain flips it the right way up when it interprets the image. After such a procedure (surgical or otherwise), the image ought to form in exactly the same way (upside down) and, provided that the optic nerve was not in any way damaged by the procedure), that the brain would interpret the image in exactly the same way, so that it is flipped and seen "the right way up."
The image that forms on the retina is upside down as it is. The brain flips it the right way up when it interprets the image. After such a procedure (surgical or otherwise), the image ought to form in exactly the same way (upside down) and, provided that the optic nerve was not in any way damaged by the procedure), that the brain would interpret the image in exactly the same way, so that it is flipped and seen "the right way up."
Here is an analogy. Do you have a video camera? and can you connect it to your TV?. The lens in the camera also inverts the image (just like the eye) and the processor turns it back up the right way (just like the brain) for display. Now turn the camera upside-down. The image on the TV will then be upside-down.
...although it would only require a few days of inverted vision for the brain to adapt and perceive the images as "right-way up".
Various experimenters have examined this phenomenon. Further reading on this is available if you click the following link and scroll down to the heading TRANSFORMED VISUAL INPUT
http://www.svt.ntnu.no/psy/Bjarne.Fjeldsenden/ BlindLinkM2000/TRANSLATION-P19-48.htm
Various experimenters have examined this phenomenon. Further reading on this is available if you click the following link and scroll down to the heading TRANSFORMED VISUAL INPUT
http://www.svt.ntnu.no/psy/Bjarne.Fjeldsenden/ BlindLinkM2000/TRANSLATION-P19-48.htm
If I may be allowed to bat again...You are, of course, assuming that a video camera interprets an image in the same way that the brain does.
Also, standing on one's head tells the brain, via the semicircular canals in the ears, that the person is upside down. That is, the brain is receiving signals not just from the eye.
Standing upside down, the image should form on the retina "the right way up". The brain, used to inverting this image, turns it over so that the person sees the object upside down. In the case where only the eyeball has been inverted, and not the whole head, I still say that the person will still perceive the object "the right way up."
Also, standing on one's head tells the brain, via the semicircular canals in the ears, that the person is upside down. That is, the brain is receiving signals not just from the eye.
Standing upside down, the image should form on the retina "the right way up". The brain, used to inverting this image, turns it over so that the person sees the object upside down. In the case where only the eyeball has been inverted, and not the whole head, I still say that the person will still perceive the object "the right way up."
If the retina could be severed from the optic nerve, the eyeball rotated through 180�, and then accurately reattached in such a manner so that the upper edge of the optic nerve connected to what was the lower edge of the retina - the image would remain upright.
If the retina remained attached to the optic nerve, which would acquire a twist of 180� when the eyeball is rotated and returned to its socket - the image will initially be inverted until enough time (several days) has passed for the brain to adapt and right the image.
If the retina remained attached to the optic nerve, which would acquire a twist of 180� when the eyeball is rotated and returned to its socket - the image will initially be inverted until enough time (several days) has passed for the brain to adapt and right the image.
-- answer removed --
I remember a documentary, (late 70's?), that conducted an experiment along the lines of kempie's link.
The subject was fitted with glasses that inverted the image received by the eye - up was down and right left, and to look at your feet, you had to lift your head upwards.
Immediately after fitting, the subject was asked to pour "a cup of tea" - (a teapot of cold water and a cup) - and after waving the pot and cup about in the air and trying to move it certain directions very slowly, succeeded in making the table top very wet. Even walking was difficult.
After the week (or so?) of wearing the modifying spectacles, during which the subbject very soon adapted to walking, pouring cups of tea and many other tasks, the spectacles were removed.
At this point, being returned to 'normal vision' - the subject initially had the same difficulties she had experienced when first putting them on - ie. failing simple manual tasks, but very quickly adapted back to the previous "way of seeing the world".
The conclusion? Well, probably that there is no "correct way" of seeing the world (upside down or not) and that our brains very quickly adapt to interpreting visual input with our other senses - (for example, in the experiment, the subject quickly 'learnt' to turn her head right to see the source of a sound in her left ear)
The speed of reversion probaly had more to do with the subject's brain having 20-odd years of experience seeing things one way - and a little over a week being inverted, and therefore 'remembered' something of the old way of seeing.
So had the inversion be caused by some irreversible medical condition, it is probably reasonable to conclude that the brain would adapt quickly and easily.
The subject was fitted with glasses that inverted the image received by the eye - up was down and right left, and to look at your feet, you had to lift your head upwards.
Immediately after fitting, the subject was asked to pour "a cup of tea" - (a teapot of cold water and a cup) - and after waving the pot and cup about in the air and trying to move it certain directions very slowly, succeeded in making the table top very wet. Even walking was difficult.
After the week (or so?) of wearing the modifying spectacles, during which the subbject very soon adapted to walking, pouring cups of tea and many other tasks, the spectacles were removed.
At this point, being returned to 'normal vision' - the subject initially had the same difficulties she had experienced when first putting them on - ie. failing simple manual tasks, but very quickly adapted back to the previous "way of seeing the world".
The conclusion? Well, probably that there is no "correct way" of seeing the world (upside down or not) and that our brains very quickly adapt to interpreting visual input with our other senses - (for example, in the experiment, the subject quickly 'learnt' to turn her head right to see the source of a sound in her left ear)
The speed of reversion probaly had more to do with the subject's brain having 20-odd years of experience seeing things one way - and a little over a week being inverted, and therefore 'remembered' something of the old way of seeing.
So had the inversion be caused by some irreversible medical condition, it is probably reasonable to conclude that the brain would adapt quickly and easily.
Brachiopod is absolutely right
and there was also a tele programme with Colin Blakemore on this a little later - possibly a Royal Instit Xmas lecture.
He gave a sportsman prismatic glasses and the fella learnt to catch a ball wearing them after about 45 seconds - this means that electrical rewiring occurs in mammals like really fast.
The experiments on these lines are Sperry and Gaze, where theydid exactly your son's experiments on newts eyes
and it was around 1965. I cant rmember the results - but the answers are the same - rewiring occurs.
Ironically enough, it was Blakemore's experiments on vision (kittens) which LOST him his knighthood. Not popular with the civil servants in the Knighthood Office,and he was blue pencilled - luckily some undersecretary managed to find a labout party donor to fill in the vacant space.
Oh, and also google synaesthesia, that's where you hear music and see colours
and once you have read it, you will see that it is all to do with the above
and there was also a tele programme with Colin Blakemore on this a little later - possibly a Royal Instit Xmas lecture.
He gave a sportsman prismatic glasses and the fella learnt to catch a ball wearing them after about 45 seconds - this means that electrical rewiring occurs in mammals like really fast.
The experiments on these lines are Sperry and Gaze, where theydid exactly your son's experiments on newts eyes
and it was around 1965. I cant rmember the results - but the answers are the same - rewiring occurs.
Ironically enough, it was Blakemore's experiments on vision (kittens) which LOST him his knighthood. Not popular with the civil servants in the Knighthood Office,and he was blue pencilled - luckily some undersecretary managed to find a labout party donor to fill in the vacant space.
Oh, and also google synaesthesia, that's where you hear music and see colours
and once you have read it, you will see that it is all to do with the above
sorry - made a bit of that up. I obviously wasnt listening when I got lectured on Sperry's experiments. Lucky I wasnt asked a q on that in my finals, I would have got an even worse degree!
R L Gregory - Eye and Brain, (weidenfeld, 1966, in itself a collector's item apparently) says p 209, "The hens were severely disturbed and they showed no real improvement after three months wearing the prisms. This same lack of adaptation has been found in amhibians investigated by Sperry. With their eyes rotated through 180' it was found that they would move their tongue in the wrong direction for food, and they would have starved if they had been left to fend for themselves. The same results were found by Hess with Chickens wearing prisms....."
and a little later: "it seems quite clear from the various experiments that animals show far less adaptation to shift or reversal of image than do humans observers, indeed only monkeys show any adaptation at all......"
The twisty eyes experiments in humans are done with prisms, and this appears to have occupied R Held, Hein, Erismann, Ivo Kohler, Stratton, J and JK Paterson, Ewert, and even Helmholtz [who first described the retinal afer-image]. Try googling X along with visual psychology and see (! Ha) what comes up.
R L Gregory - Eye and Brain, (weidenfeld, 1966, in itself a collector's item apparently) says p 209, "The hens were severely disturbed and they showed no real improvement after three months wearing the prisms. This same lack of adaptation has been found in amhibians investigated by Sperry. With their eyes rotated through 180' it was found that they would move their tongue in the wrong direction for food, and they would have starved if they had been left to fend for themselves. The same results were found by Hess with Chickens wearing prisms....."
and a little later: "it seems quite clear from the various experiments that animals show far less adaptation to shift or reversal of image than do humans observers, indeed only monkeys show any adaptation at all......"
The twisty eyes experiments in humans are done with prisms, and this appears to have occupied R Held, Hein, Erismann, Ivo Kohler, Stratton, J and JK Paterson, Ewert, and even Helmholtz [who first described the retinal afer-image]. Try googling X along with visual psychology and see (! Ha) what comes up.
Agree completely with brachiopod - you'd initially see upside down but would learn to adapt. Whether this meant that you'd actually see the world the right way round or just got the hang of the different image you see I'm less sure of.
In your brain's visual cortex, there are neurons that fire when you see an edge/line going from top left to bottom right. That neuron wouldn't fire if you were receiving a different image so that's why I'm unsure about you actually seeing everything the right way round after adapting to your upside down eyes.
I think the function of these neurons were first discovered in a brilliantly titled bit of research called "What the frog's eye tells the frog's brain" :-)
In your brain's visual cortex, there are neurons that fire when you see an edge/line going from top left to bottom right. That neuron wouldn't fire if you were receiving a different image so that's why I'm unsure about you actually seeing everything the right way round after adapting to your upside down eyes.
I think the function of these neurons were first discovered in a brilliantly titled bit of research called "What the frog's eye tells the frog's brain" :-)
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