Why does our brain invert the image received from our eyes?

[Pythagorean]

Though, I think the developmental story would still be about computation and efficiency (and efficiency pertains to availability), just not among neurons alone, so much as genetic code and protein signaling and the whole complicated set of processes involved in life.

 

[madness]

I still haven't worked out why any configuration would require more computation than another. I don't think there is any "right way up" and "upside down" as Dave wrote, just conventions that we've grown used to. Even if our proprioception was inverted with respect to our vision, we would just experience the world like looking in a mirror and that would seem normal to us.

 

[russ_watters]

Indeed it does, but it can only "correct" the image up to a certain angle.

True... another useful effect of this I can see is that it acts as as a sort of built-in image stabilization. Try bobbing your head from side to side (not too many times!) and see how the image stays pretty stable.

 

[Evo]

I still haven't worked out why any configuration would require more computation than another. I don't think there is any "right way up" and "upside down" as Dave wrote, just conventions that we've grown used to.

Try standing on your head for 8 hours (don't really do this) and tell me that there is no up or down. For example, if our brain didn't correct the image and we saw an uncorrected upside down and reversed image, the sky would be at the bottom and the ground would be at the top.

 

[Pythagorean]

Try watching tv lsideways or upside down. In the time before you adapt, you might find it somewhat laborious to interpret the screen sideways.

To continue withe the my other analogy, try using a map that's backwards to navigate. It requires an extra step to transform from one coordinate system to another.

Even if up and down are just conventions, we still want up on our map to match up in the world, however we define it (wrt gravity most commonly).

 

[zomgwtf]

I'm failing to make sense of what many people here are claiming. If we perceived naturally the inverted image it would not make a difference to 'up-down' orientation. It would be normal for us to see that way and this way would still be this way even if to our present normal vision it would be backwards. I do not think there would be any difference in efficiencies... this is just the way we've evolved. If we evolved seeing the world inverted it wouldn't make the slightest difference.

It seems people seem to be thinking that if we pereived things as being inverted we would have to think about what we're seeing in order to know what's going on... what they fail to accoutn for though is that our brains would be acustomed to the 'invertedness' of our vision and it would just be normal. If I wanted to go to the door that is on my left right now my brain would still perceive where the door is relative to my position and I would be able to move as such to get to the door.

 

[zomgwtf]

Try standing on your head for 8 hours (don't really do this) and tell me that there is no up or down. For example, if our brain didn't correct the image and we saw an uncorrected upside down and reversed image, the sky would be at the bottom and the ground would be at the top.

This analogy isn't too great I'd say. If you were to stand on your head for 8 hours you wouldn't be inverting your perception, it's completely different. Your perception is still normal but you are upside down relative to your normal position.

If your vision were to truly be inverted it would be your normal position that everything else is relative to.

 

[Monique]

I'm failing to make sense of what many people here are claiming. If we perceived naturally the inverted image it would not make a difference to 'up-down' orientation. It would be normal for us to see that way and this way would still be this way even if to our present normal vision it would be backwards. I do not think there would be any difference in efficiencies... this is just the way we've evolved. If we evolved seeing the world inverted it wouldn't make the slightest difference.

It seems people seem to be thinking that if we pereived things as being inverted we would have to think about what we're seeing in order to know what's going on... what they fail to accoutn for though is that our brains would be acustomed to the 'invertedness' of our vision and it would just be normal. If I wanted to go to the door that is on my left right now my brain would still perceive where the door is relative to my position and I would be able to move as such to get to the door.

Exactly, that is also my interpretation.

 

[zomgwtf]

Try watching tv lsideways or upside down. In the time before you adapt, you might find it somewhat laborious to interpret the screen sideways.

So you're going to argue that with our normal present perception if we were to try and force it to work differently it would require extra work and you think that's a good argument?

To continue withe the my other analogy, try using a map that's backwards to navigate. It requires an extra step to transform from one coordinate system to another.

See above.

Even if up and down are just conventions, we still want up on our map to match up in the world, however we define it (wrt gravity most commonly).

Some how if we invert our vision our brain will no longer be able to determine what is above us and what is below us RELATIVE to us?

 

[russ_watters]

I'm failing to make sense of what many people here are claiming. If we perceived naturally the inverted image it would not make a difference to 'up-down' orientation. It would be normal for us to see that way and this way would still be this way even if to our present normal vision it would be backwards. I do not think there would be any difference in efficiencies...

Try examining the issue from the opposite direction: Our brains are making a correction (actually, quite a lot of them from the examples given). If this correction was unnecessary, then there should have been no evolutionary pressure to make our brains wire themselves that way.

 

[zomgwtf]

Try examining the issue from the opposite direction: Our brains are making a correction (actually, quite a lot of them from the examples given). If this correction was an unnecessary, then there should have been no evolutionary pressure to make our brains wire themselves that way.

Corrections? I thought I already stated that if we just perceived the world as inverted everything would be inverted and perceived as normal... there's really no 'correction' here... If we still knew 'left-right-up-down' in such a world those directions would still travel with us to our new perceptions... they wouldn't be the same directions though if you looked at one from the other perspective. They'd be inverted, of course.

It's hard to explain it but the directions are actually relative to us... there is no objective 'up' direction to perceptions. The only thing objective about up is that it is above us...

And evolutionary pressure? I assume you are trying to say that all things that happen in biology due to evolution must be a 'good' or 'positive' change? Or that the changes are for the benefit of the organisms? This may very well be true, in regard to our vision, but I do not think any of the reasons listed about computational advantage or efficiencies are involved at all.

 

[russ_watters]

Corrections? I thought I already stated that if we just perceived the world as inverted everything would be inverted and perceived as normal... there's really no 'correction' here... If we still knew 'left-right-up-down' in such a world those directions would still travel with us to our new perceptions... they wouldn't be the same directions though if you looked at one from the other perspective. They'd be inverted, of course.

Are you saying that you don't notice a difference in the way the world looks when you flip yourself upside down nor do you notice that after a while that difference goes away?

Our brains do manipulate up and down in the processing of our vision.

The way I first read your objection was that you believe that this correction was unnecessary: that if the correction wasn't made we'd still be able to learn to coordinate motion just as easily as we can with this correction applied.

 

[zomgwtf]

Are you saying that you don't notice a difference in the way the world looks when you flip yourself upside down nor do you notice that after a while that difference goes away?

Our brains do manipulate up and down in the processing of our vision.

Yeah relative to what is already normal.. not relative to any objective standard of direction.

If it was normal from the beginning to be 'inverted' then that would mean the new inverted is the old normal. Maybe then we would be thinking about how weird and crazy it would feel to live in a world where we pereived things as inverted (normal to us now) but as far as I can see things look pretty normal!

EDIT: In response to the added bit, that is exactly my objection with the exception about 'learn to co-ordinate motion'. We wouldn't 'learn' anything it would just be normal, w would do it the same way we do now... because everything we perceive is always relative to us.

 

[Monique]

Try examining the issue from the opposite direction: Our brains are making a correction (actually, quite a lot of them from the examples given). If this correction was unnecessary, then there should have been no evolutionary pressure to make our brains wire themselves that way.

Actually, the example you've given (about watching television at an angle) is caused by the brain interpreting the rotation of your head: it takes into account the signal from the vestibular system in your ear. This is to correct for the movements that your head makes during every day life. Chickens have their own system to stabilize their vision, watch this video:

 

[russ_watters]

...btw, I thought of a good reason why the images need to be corrected: binocular vision. If the image orientation wasn't corrected, then our depth perception and even the overlay of the two fields of view themselves wouldn't work.

 

[russ_watters]

Actually, the example you've given (about watching television at an angle) is caused by the brain interpreting the rotation of your head: it takes into account the signal from the vestibular system in your ear.

Yes, I understand that. It takes an input from our internal gyro and uses it to correct the orientation of the picture. I suspect it also does the same thing when we stand on our head and after a while the image flips. So that fits just fine with my point: the brain is making a correction. If this correction was unnecessary, why bother?

 

[zomgwtf]

...btw, I thought of a good reason why the images need to be corrected: binocular vision. If the image orientation wasn't corrected, then our depth perception and even the overlay of the two fields of view themselves wouldn't work.

I think it would still work... the only reason it seems to us that the images on our retina are inverted is because our brain has adjusted to seeing things 'upright' because they are normal relative to our natural perception.

 

[russ_watters]

I think it would still work... the only reason it seems to us that the images on our retina are inverted is because our brain has adjusted to seeing things 'upright' because they are normal relative to our natural perception.

Try this: hold your hands out in front of you, palm toward you, fingers pointed up. Notice that your pinkies are next to each other. Now rotate your hands 180 degrees so both are facing down. Notice that your thumbs are now next to each other. If your brain overlaid the pictures on top of each other without re-arranging them either by switching their left/right positions or by rotating the image of each eye, they wouldn't line up.

Btw, you didn't respond to this:

the brain is making a correction

I want to make sure we are at least understanding the other's point: do you agree that your brain does rotate images?

 

[zomgwtf]

Try this: hold your hands out in front of you, palm toward you, fingers pointed up. Notice that your thumbs are next to each other. Now rotate your hands 180 degrees so both are facing down. Notice that your pinkies are now next to each other. If your brain overlaid the pictures on top of each other without re-arranging them either by switching their left/right positions or by rotating the image of each eye, they wouldn't line up.

Hmmm I am pretty sure that 'uprightness' is a function of the brain after all perception is completed. I might be wrong here though.

What this means though, if I'm right, is that your brain has already overlayed the images correctly and they are already lined up, albeit inversed to how you think you are seeing things. That's my entire point though, if the brain didn't switch things to 'see upright as normal' you would still perceive things as normal, as long as you didn't effect your vision. So if we lost this ability to adjust to perceptions then when we put on those glasses Monique spoke of we would no longer be able to see things as upright anymore, they would permanently look inversed to us and we would have to conciously learn how to function with such vision. This 'correction factor' you talk about does that automatically for us...

I think you've mentioned this already a few posts back I just don't agree with it increases efficiency in a normal perceptive state. Things would just look normal all the time...

EDIT: didn't see the last prat of your post. I do agree with what you call a correction but I disagree that it is a 'correction' in that there is an objective orientation to the world. It is a correction in the sense that thinking upright is easier for you at all times. But under normal circumstances (without technology to invert our vision) this wouldn't be very useful... things would always still appear normal... unless you held your head in an awkward position for an extended period of time..

For instance: If you put on those glasses which invert the image you see prior to it entering your retina and then your brain adjusts to seeing it as 'normal' does that mean that what you are seeing now is the 'real' normal? No, your brain still just adjusted to the new orientations relative to yourself, and it'll do this for all situations. Without which we would still see things as 'normal' and upright we just wuoldn't be able to adjust to different perspective orientations sub-conciously.

 

[russ_watters]

What this means though, if I'm right, is that your brain has already overlayed the images correctly and they are already lined up, albeit inversed to how you think you are seeing things.

You didn't respond to the thought experiment: they can't be lined up if they are inverted.

If you built a model of your eye and looked at what was projected on it, you'd see this: [attached]

If your brain didn't reorient the images either by switching the left and right images or by rotating both, they wouldn't be overlaid properly.

 

[zomgwtf]

You didn't respond to the thought experiment: they can't be lined up if they are inverted.

If you built a model of your eye and looked at what was projected on it, you'd see this: [attached]

If your brain didn't reorient the images either by switching the left and right images or by rotating both, they wouldn't be overlaid properly.

No what I'm saying is that the overlaying and those adjustments occurs prior to 'upright' adjustment factors. If what you were sayin were true then when you wore the inversion glasses that should be what you see, but it isn't because your brain already pieces the image together prior to everything being adjusted to "upright".

Also that's just what is seen in the retina prior to brain processing the information. Uprightness and overlay/depth perception are different processes. If we didn't have the ability to adjust for 'uprightness' we would still process the image overlay etc. That was what I was trying to say earlier .

 

[russ_watters]

EDIT: didn't see the last prat of your post. I do agree with what you call a correction but I disagree that it is a 'correction' in that there is an objective orientation to the world.

Ok, that's what I thought. You agree that the brain is doing some processing work here, but you think it is unnecessary: you think that if the brain didn't do that processing work, we'd have learned a different "normal" and we'd never know the difference.

In that case, you are arguing that the brain evolved a function that it doesn't need. Why would it do that?

 

[russ_watters]

No what I'm saying is that the overlaying and those adjustments occurs prior to 'upright' adjustment factors. If what you were sayin were true then when you wore the inversion glasses that should be what you see, but it isn't because your brain already pieces the image together prior to everything being adjusted to "upright".

What are "inversion glasses"?

Also that's just what is seen in the retina prior to brain processing the information. Uprightness and overlay/depth perception are different processes. If we didn't have the ability to adjust for 'uprightness' we would still process the image overlay etc. That was what I was trying to say earlier .

So you're sying this happens:?

1. Image hits retina oriented as in the picture I showed.
2. Brain corrects the left/right orientation of the images.
3. Brain stiches the images together.
4. Brain rotates the entire image upright.

Now you've added two steps that I thought you were saying were unnecessary. Why doesn't the brain just do this:

1. Image hits the retina.
2. Brain stiches the images together like the picture I showed.

Or:

1. Image hits the retina.
2. Brain rotates images upright.
3. Brain stiches images togehter.

The first would work, but takes more processing steps. The second wouldn't work at all. The third is most efficient.

But you were suggesting upright wouldn't need to be upright. So it could have done this:

1. Image hits the retina.
2. Brain corrects the left-right orientation.
3. Brain stitches the images together (leaving them upside-down).

 

[zomgwtf]

Evolution doesn't work base on what's needed or what's better, it just works based on the history of things. I'll have to look further into it to see if there indeed is an evolutionary advantage to the brain adjustment for uprightness but right now I have to go to work :P. I shall respond later.

 

[Monique]

Here is another interesting article: http://www.smbs.buffalo.edu/acb/neuro/lectures/Vision-Ramachandran.pdf"

The lens in your eye casts an upside-down image on your retina, but you see the world upright. Although people often believe that an upsidedown image in the eyeball gets rotated somewhere in the brain to make it look right-side up, that idea is a fallacy. No such rotation occurs, because there is no replica of the retinal image in the brain—only a pattern of firing of nerve impulses that encodes the image in such a way that it is perceived correctly; the brain does not rotate the nerve impulses.
Even leaving aside this common pitfall, the matter of seeing things upright is vastly more complex than you might imagine, a fact that was first pointed out clearly in the 1970s by perception researcher Irvin Rock of Rutgers University.

Figure F is really striking.

 

[Proton Soup]

Here is another interesting article: http://www.smbs.buffalo.edu/acb/neuro/lectures/Vision-Ramachandran.pdf" Figure F is really striking.

Instead your brain figures
out which way is up by rely-
ing on feedback signals sent
from the vestibular system in
your ear

yup, first thing i thought about before even opening it.

 

[Monique]

I'm seeing vagueness, confusion, lack of definitions, grand leaps into metaphysical speculation, and nonsense like "0 gravity".

To get back on the comment that gravity has nothing to do with it. Here is an interesting publication that illustrates how our brain can misinterpret its sensory information and make a wrong decision on orientation.

Even in the absence of any structural or developmental abnormalities, vestibular stimulation can cause spatial disorientation, illusory postural and visual perceptions, and disabling motion sickness. The central nervous system already has a difficult time on Earth differentiating linear acceleration owing to translation from tilt with respect to gravity. [..] In space, tilt is not defined because there is no vertical orientation defined by gravity. [..] If an astronaut has adapted such that utricular signals are interpreted only as owing to head translation, then tilting the head when back on Earth causes the illusion of translation. When bending to the side to release an emergency brake, one astronaut involuntarily guarded against an impending collision with the roof of the car because the gravitational pull on the utricle was misinterpreted as an upward linear translation.

http://archneur.ama-assn.org/content/vol64/issue4/images/medium/nnr60015f3.jpg

http://archneur.ama-assn.org/cgi/content/full/64/4/485#SEC2"

Interestingly, this shows that we need the input of gravity to define our 3-dimensional world and that indeed when this is messed up you "jump instead of duck" in a situation of danger (like how it was mentioned earlier in this thread).

 

[lorax_2nd]

I feel a bit woozy, but think I am dumber now after having read this thread, than before I came. Which isn't easy to do, because I'm fairly stupid to begin with.

Once upon a time, when someone wanted to ask a physics question, they had to take the effort to physically go find someone acknowledged as a physics 'expert' (or, the usual substitute: your local jr. high physics teacher), and if that person wanted to give a more thoughtful answer than whatever came off the top of their head at the moment, they had to physically go to a repository of information (or, the usual substitute: their dusty bookshelf) and consult tomes of peer-reviewed articles, or for more general questions, textbooks. This forced people to invest time in learning, and sometimes, that investment filtered out some nonsense.

Now, someone can post an ill-framed question that popped into their head 10 seconds ago, have it seen by thousands, and be responded to by anonymous anyones (like me) with answers that just popped into their own head, or possibly worse, with googled keyword articles. Again, I have to ask, is a useful piece of physics being learned, or do I fundamentally misunderstand the purpose of a physics forum?

As for the charge of disrespect: I'll plead guilty, yer honor. Respect me if I give a clear, concise answer with my assumptions defined, terms commonly used and understood, and conclusion relevant to the original question, and I'll do likewise.

I genuinely feel bad for sounding like such a curmudgeon, but I can't help but express my disappointment, even if I'm just saying it to myself, and seeing it in print, and inflicting my opinion on other people. ...And so doing no better than what I'm criticizing...

 

[zomgwtf]

I feel a bit woozy, but think I am dumber now after having read this thread, than before I came. Which isn't easy to do, because I'm fairly stupid to begin with.

Are you being serious? If you know the definitive answer then post it with some citations. Which posts make you feel 'dumber' than you already had been?

Once upon a time, when someone wanted to ask a physics question, they had to take the effort to physically go find someone acknowledged as a physics 'expert' (or, the usual substitute: your local jr. high physics teacher), and if that person wanted to give a more thoughtful answer than whatever came off the top of their head at the moment, they had to physically go to a repository of information (or, the usual substitute: their dusty bookshelf) and consult tomes of peer-reviewed articles, or for more general questions, textbooks. This forced people to invest time in learning, and sometimes, that investment filtered out some nonsense.

Really? There are some pretty knowledgeable people in the field of biology on these forums and yes, they have made posts in this thread. I'm no expert (yet at least I'm studying to) and if something I've said is wrong could you point it out?... if something anyone has said is wrong why don't you just point it out? Instead of this unnecessary posting?

Now, someone can post an ill-framed question that popped into their head 10 seconds ago, have it seen by thousands, and be responded to by anonymous anyones (like me) with answers that just popped into their own head, or possibly worse, with googled keyword articles. Again, I have to ask, is a useful piece of physics being learned, or do I fundamentally misunderstand the purpose of a physics forum?

I doubt that the people on these forums did a simple google keyword search and threw non-sense out there. This isn't physics being discussed here... in fact it's FAR removed from physics. Just because the forums name is PhysicsForums doesn't mean everything discussed on the forums is related to physics. The posed question has to do with the necessity of our brain 'correcting' for inversion of our vision.

As for the charge of disrespect: I'll plead guilty, yer honor. Respect me if I give a clear, concise answer with my assumptions defined, terms commonly used and understood, and conclusion relevant to the original question, and I'll do likewise.

Where was your concise answer again? All I read was you explaining that what we see is inverted and why it was inverted... I might have missed something though. By the way when you see something inverted it doesn't mean your hands are moving towards your feet and you see them moving some other way.

 

[zomgwtf]

Hmph forgot to come back to respond to this thread.

What are "inversion glasses"?

Glasses you wear on your eyes which invert what you are seeing.

So you're sying this happens:?

1. Image hits retina oriented as in the picture I showed.
2. Brain corrects the left/right orientation of the images.
3. Brain stiches the images together.
4. Brain rotates the entire image upright.

No I don't think that's what I was saying. I was saying this:
1. Image hits retina
2. Image gets assembled correctly (so we see it as one seemless image that is)
3. Image appears 'upright' automatically, it's not 'rotated' it just looks upright because it's normal to see things that way.

Point 3 is what I've been trying to point out. It just 'happens' as a 'correction' (I can't think of a better word... it's really not a correction though) So while the image received very well may be inverted our brain forces us to perceive it 'upright' because it's the norm. We are used to observing things in that orientation and this orientation is based on our body. This is honestly a very confusing thing to try and explain... I may be wrong in my thinking but this is just what I've been trying to explain here in this thread.

1. Image hits the retina.
2. Brain stiches the images together like the picture I showed.

This is basically what I think goes on with the exception that the brain automatically perceives the image as upright, because it is normal to the brain. As I said before you can put on the inversion glasses and after awhile things appear normal, this is your brain automatically forcing you to perceive things as upright based on your body.

Why is this needed though? That's the OPs question. After reading the article that Monique posted it became clear to me why it would be necessary to make this 'correction'... I don't even know why it never occurred to me in the first place, I think someone already mentioned it earlier though. I believe it would be necessary to make this correction in order for things in the outside world to appear upright regardless of our bodies orientation. So if I'm laying down on my side I know where up is still in relation to my bodies normal position. (upright) Sorry for dragging this out if this was what you're original point was russ. I just didn't agree with the efficiency part of consciously thinking where things were, that just didn't make sense to me since it would just be the norm for our brain.

1. Image hits the retina.
2. Brain corrects the left-right orientation.
3. Brain stitches the images together (leaving them upside-down).

I do not believe it is left upside-down. The brain just automatically forces you to perceive the image upright.

 

[lorax_2nd]

Are you being serious? If you know the definitive answer then post it with some citations. Which posts make you feel 'dumber' than you already had been?

Where was your concise answer again? All I read was you explaining that what we see is inverted and why it was inverted... I might have missed something though. By the way when you see something inverted it doesn't mean your hands are moving towards your feet and you see them moving some other way.

You're right, my last post wasn't realistically constructive. Upon re-reading the whole thing, based upon the OP's subsequent posts, it seems clear that he wasn't looking for a brief, simple physics answer, but rather appreciated the thread's various discussions.

That's not my cup of tea, so ... I'm moving along... :)

 

[Monique]

Once upon a time, when someone wanted to ask a physics question, they had to take the effort to physically go find someone acknowledged as a physics 'expert' (or, the usual substitute: your local jr. high physics teacher), and if that person wanted to give a more thoughtful answer than whatever came off the top of their head at the moment, they had to physically go to a repository of information (or, the usual substitute: their dusty bookshelf) and consult tomes of peer-reviewed articles, or for more general questions, textbooks. This forced people to invest time in learning, and sometimes, that investment filtered out some nonsense.

Now, someone can post an ill-framed question that popped into their head 10 seconds ago, have it seen by thousands, and be responded to by anonymous anyones (like me) with answers that just popped into their own head, or possibly worse, with googled keyword articles. Again, I have to ask, is a useful piece of physics being learned, or do I fundamentally misunderstand the purpose of a physics forum?

There you go again with your disrespect. May I summarize the source that I have cited? Here they are:

• G. M. Stratton, Third International Congress for Psychology, Munich, August, 1896
• L.E. White, D. Fitzpatrick, Neuron. 2007 Oct 25;56(2):327-38.
• V.S. Ramachandran and D. Rogers-Ramachandran, Scientific American Mind, July 2007
• R. Kalb; D. Solomon, Archives of Neurology, 2007;64(4):485-490.

Get out of your little box.

As for the charge of disrespect: I'll plead guilty, yer honor. Respect me if I give a clear, concise answer with my assumptions defined, terms commonly used and understood, and conclusion relevant to the original question, and I'll do likewise.

You think you can understand the brain, by explaining the properties of light and the optics of the eye. Check the source again that I cited, by Dr. Ramachandran. Apparently you are not familiar with his work, so let me introduce him: he is http://cbc.ucsd.edu/ramabio.html" .

I genuinely feel bad for sounding like such a curmudgeon, but I can't help but express my disappointment, even if I'm just saying it to myself, and seeing it in print, and inflicting my opinion on other people. ...And so doing no better than what I'm criticizing...

You may want to educate yourself and actually read up on the sources given.

 

[zomgwtf]

You're right, my last post wasn't realistically constructive. Upon re-reading the whole thing, based upon the OP's subsequent posts, it seems clear that he wasn't looking for a brief, simple physics answer, but rather appreciated the thread's various discussions.

That's not my cup of tea, so ... I'm moving along... :)

Hey, there's nothing wrong with adding additional details that you think might be interesting to someone, I'm sure SOMEONE who stumbles across this thread will find it interesting. However there are ways to go about responding to people on the forum and the way you've chosen isn't one of them. This obviously doesn't apply to just the forum it applies to your outside life, you should always try to remain respectful towards others especially people like Monique who are very respected individuals. I like that you've taken the time to understand and accept that your criticisms of the thread are wrong but you should still try to be more respectful towards others on the internet and in the real world. I know I've crossed the line into disrespecting others before on the forums and in real life and really, it's not worth it.

 

[Imponderabili]

In case nobody pointed that out before:

There is no need to invert the image!

You only have to invert the image if there is an absolute reference system (within the brain) to which we need to correct the received image. Remember that the image in the brain is not a real image - it is a representation of an image, a package of information entangled in neuronal activity.

The whole answer to inversion-problem is development:
our brains are very plastic in the early years - they learn to understand some parts of the visual field as 'top' and some as 'bottom' due to gravity, reference to our body and learning to move and interact with environment.
This understanding can be later remapped when sensorimotor contingencies change - like in the case of oculars that invert the image.
But the image does not have to be changed anyway. To think that it has is similar to thinking that when you are playing a computer game and your character dies - there is an actual character dying somwhere inside the computer.

 

[TylerH]

First: There is an a absolute reference system for orientation, it's in the inner ear.

Second: It makes sense to flip the image because the image is upside down. Light comes into your eye at an angle that causes light coming from above you to hit the bottom side of the inside of your eye. It just makes more sense to view the world as it is.