I disagree with the author's interpretation of this.
As a neurologist myself, I was taught it was specifically to simplify visual processing, although there may be other theories but this is what I was taught. Like others commenting here, the way the lens works in each eye is by flipping the image onto your retina. If we had only one eye, there would be no issue, the image would appear as a continuous image, just flipped around. However, because we have two eyes, they both individually flip different fields, thus separating the continuity of the image horizontally. If you try drawing out various different ways to try and remedy this problem of binocular vision, the way nature's approach is quite elegant in reuniting the image as well as separating visual processing into left/right.
The way it works is by separating the left and right fields of each eye, and then crossing them so that the left fields goes to the right half of the brain and the right fields go to the left half of the brain. Each right/left half is now interpreted by one side of the brain and the image is again continuous if you draw it out on the brain. Of course now each side of the brain sees the opposite side, but we remedy this by crossing everything else so it plays well with visual interpretation. Now the right side of the brain sees, senses, and controls the left side of the body and vice versa.
When it comes to everything else, there isn't a clear benefit for having processing swapped to opposite hemispheres. But visual processing benefits from it greatly, and so the rest of the nervous system goes along with it.
I don't think you understood the author's interpretation well enough to say you disagree with it.
The problem you describe, of mapping binocular vision is an example of the topological problem described by the author. But it's not the only example: feeling nerves, for example, have the same symmetrical problem with mapping your skin sensations to the physical space, and your hearing also is "binocular" (there's actually a separate word for this, "binaural"). The visual problem you're describing is part of the topological problem. You're describing the same problem, but you're describing a part of the problem.
Where you're just wrong is on two points:
1. "When it comes to everything else, there isn't a clear benefit for having processing swapped to opposite hemispheres." Wrong. As mentioned before, binaural hearing also needs to map a 3d topology to a 2d topology from two data collection points, and skin needs to map a 3d topology from many more points (but also symmetrical). Additionally, the effect works on "outputs" as well as "inputs", mapping the 2d space to a 3d space so that you can control symmetrical tools such as your arms and legs means that the swapping is needed when sending signals outward as well.
2. "[V]isual processing benefits from it greatly, and so the rest of the nervous system goes along with it." Vision is not the evolutionary driver here. The criss-crossed neurology predates the existence of vision in our evolutionary heritage. The article mentions worms, for example: how does your hypothesis explain why their nerves crossed hemispherically given they don't have lenses and retinas?
I think the eye example is in fact different because light passing through the lense is inverted onto the retina as the root comment explains, there's no such inversion for perceiving other senses. I find the explanation intuitively appealing at first, but given connections are criss crossed for far simpler animals such as worms like you mention, I don't think the idea that vision is the primary driver of this phenomenon is correct.
I only have one eye (retinoblastoma) and have never been able to see through my left eye, you can't imagine the amount of questions that just arrived in my head, do you have some material to explain this a bit more? Specially in regards to the flipping different fields? Thanks so much!
I agree that we don't know, but we can weight the different possible explanations by plausibility.
The article's explanation would explain all the facts we do know, so we can reasonably weight that as a very plausible explanation. I'll also add that the article says, 'Now, this all makes sense mathematically, but it’s important to note that we don’t know for certain that this is truly why our brains and bodies are connected the way they are. There is very little biological research on this intriguing question. The convenient dodge often heard is that the scientific method tells us “what,” not “why.”'
The GP's explanation doesn't explain why worms have criss-crossed nervous systems despite not having retinas or lenses, and it incorrectly assumes that other systems don't benefit from a criss-crossed nervous systems, so we can reasonably weight the GP's explanation as highly implausible.
To be mobile and agile in a three dimensional world, a creature needs to be able to process information about its environment such as adjacency, and direction - that is, the relationship of different parts of space, or things in space, to one another, matters a lot to the organism. You could store store each individual perceivable bit of spacial information randomly, but then to get this structural information you'd need an elaborate mapping layer that allowed the brain to compute distance and direction. It's far simpler to rely on actual spatial relationships in the cortex to model the structural information by mapping it to an analogous spatial structure information. Simpler means less energy in construction and operation of the facility, and that wins out in an evolutionary race.
> Of course now each side of the brain sees the opposite side, but we remedy this by crossing everything else so it plays well with visual interpretation.
Why? I don’t understand the logic of what you’re theorising. If your right side is damaged, why does having your ipsilateral side help? How common would this have been from an evolutionary perspective? And if your right side is damaged, and it’s taken out your right brain, now you’ve got a right side that doesn’t work and a left side you can’t control
That was my intuitive first thought, but a healthy left brain stuck trying to control a crippled right body is a worse situation than a healthy left brain controlling a healthy left body and merely deadweight on the right.
Thanks for the explanation, it makes much more sense than the original article and the attached image was not even necessary for me to "get" the idea while many paragraphs and diagrams just left me confused before reading it.
The flip is both vertical and horizontal. Imagine all the rays converging at the focal point and carrying on. Each ray ends up on the opposite side of the centre of the image. Up->down, left->right, etc.
Tangentially related to this is when I installed a patio in my yard two summers ago. Okay, let me explain:
I had a sugar maple about 3 feet away from where I had to dig the foundation for the patio. An arborist said that it’s a bit close but the maple is strong and it should recover fine.
I cut out a bunch of roots and within a month the exact sections of the canopy corresponding to the roots I cut went brown.
It was incredible to me how the roots relate directly to the canopy. I always kinda thought it was one big circulatory system, where everything supports everything. I expected the whole tree to struggle a bit.
Next season the tree was fully recovered.
The neurological system seems to work the same way? It’s a directed graph where one root supports a very specific set of branches? I guess the circulatory system is like that too if you separate the two sets. Nature doesn’t really like cyclic graphs, does it?
> I cut out a bunch of roots and within a month the exact sections of the canopy corresponding to the roots I cut went brown.
Root systems in general (for trees at least) mirror what's happening above ground. Pruning trees is a beneficial intervention, as it causes the corresponding roots to die and decompose. This not only makes precious biomatter available for recycling by the microorganisms in the soil, but also releases chemical signals that cause the tree itself and neighbouring plants to send out new growth.
When I worked for the park service, my botanist boss told me that the reason junipers and that sort of scrubby, stress-tolerant tree have twisty trunks is so that if they lose a section of roots they don't lose a sector of sunlight in the canopy. Because sunlight can be focused on one side of a tree (especially if growing on a steep slope), a twisting trunk can save a tree in the case of root damage on one side.
> Nature doesn’t really like cyclic graphs, does it?
I had a course in computational neuroscience as part of my bachelor's and one of the things that we covered was that the timing of fires is important, in that depending on how soon before or after a neighbouring neuron fires, the connection may be weakened or strengthened. This is called Spike-timing-dependent plasticity:
> Under the STDP process, if an input spike to a neuron tends, on average, to occur immediately before that neuron's output spike, then that particular input is made somewhat stronger. If an input spike tends, on average, to occur immediately after an output spike, then that particular input is made somewhat weaker hence: "spike-timing-dependent plasticity"
From [1].
The implication of that, I believe, is that it prevents short cyclic graphs, for the sole reason of avoiding feedback loops that can cause the brain to go haywire (lol) due to the feedback loop. It sounds like an evolutionary adaptation to prevent short-circuiting.
From Hebbian Learning, we have that the cycles would become easier to trigger, meaning that it is a feedback loop that increases efficiency, however, without a mechanism to prevent this cyclical feedback loop, the brain could be filled with cycles that eventually turn to just rings, which is probably not a desirable property.
If anyone knows more about this please tell me. If it's a new idea, please remember to add my name :')
just keep inmind, this, and other phenomenon dont happen in all neurons, or in any particular neurons 100% of the time.
neurons change functional, and structural state, depending on past events [hysterisis] and will shut down/modify state activities depending on feedback from post synapic neurons.
also neurons will get tired and handoff activity to similar neurons in a cohort.
Its very much not a directed graph. We do have brain loops. That's where brain waves come from, circular paths of neurons activating themselves in a circular firing squad.
There's a theory that says an ancestor of all vertebrates just flipped its head around and it stayed that way. (Source: https://arxiv.org/abs/1003.1872). Can someone who knows more about animal physiology explain this paper? Thanks.
But that issue is related to the fact that insects have their nerves in the inferior part of their bodies, and the digestive tract on top, while we have our nerves in the back (protected by bones), and the digestive tract on the front, which would be the lower part if we were still walking with four limbs.
The issue described here is left-right symmetry, and it also applies to insects, so it is more general.
So far I have read that these are related theories and the "somatic twist" theory is an expansion on the earlier theory of inversion. And there seems to be another related but separate theory called the axial twist theory (explained in the linked paper).
I had always presumed this was the reason, and just assumed that crustaceans, insects, etc. didn't have bilaterally crossed nervous systems. However, the linked article mentions nematodes also having a nervous system with bilaterally crossed connections, so it can't be the entire story (and it seems my assumptions about crustaceans, insects, etc. is wrong).
This should be the top comment here: a reference to an actually scientific analysis that uses an argument that is plausible from an evolutionary perspective.
E.g.: someone else here was arguing that maybe the mirroring helps the brain keep processing inputs from the side that was hit. Evolution does not work this way! Flipping doesn’t “just” happen, that’s a huge morphological change. It had to have evolved incrementally, with each intermediate step having an immediate benefit.
The paper explains how and why this may have occurred.
> Flipping doesn’t “just” happen, that’s a huge morphological change.
In some primitive ancestor, it might have 'just' happened randomly. Some mutations that are small in genetic code terms can have huge effects on body structure.
You say that, however, there is still no convincing scientific explanation for irreducible complexity in evolution. Interestingly, this paradox is exemplified best by the irreducible complexity in the nature of the eyes
I'm surprised the article and comments haven't mentioned the axial twist hypothesis [0], which IMO is the best explanation I've seen so far for contralateral wiring. The axial twist hypothesis has experimental evidence and is also predicted from physical first principles of what is known about embryonic development. It explains the central decussation, which is a stronger prediction than the existence of some decussation (from what I understand of the article). I still don't quite understand how one gets from the existence of a decussation between two distinct body-cortex paths to contralateral organization, but maybe after reading the paper I will get it.
After an explanation that without L/R crossing the body map in the brain would be flipped upside down, comes this revealing passage:
"To make sense of the sensation [...] your brain would have to switch from one somatotopic map to another one with the opposite z-axis orientation".
This a textbook example of the "Cartesian theater" fallacy. It assumes a little person inside the brain who has to deal with an image projected upside-down. Of course that doesn't make sense.
Slightly related: there’s a YouTube video [1] of a guy teaching himself how to ride a bicycle “in reverse”, i.e. you turn left, and it goes right. It takes some practice but in the end it just “clicks”. So now he’s balancing and moving completely opposite to perception.
So you’re right about the little man. I struggle to see why some arbitrary axis transform is “too hard”.
I vaguely remember reading about some similar experiments with goggles that mirrored vision. As I remember, after a few days, people can mostly overcome the difficulties of having their vision reversed.
to counteract your point though he does struggle a lot, and he does find riding the bicycle the usual way very hard after that. if you watch the video you can see him falling over and over
The pictures with the finger at the end are even more confusing. They conflate the mapping from body parts to cerebral cortex (the cortical homunculus) with the mapping from the homunculus to some other part of the brain were the 3D environment is allegedly mapped. They don't make sense to me.
I still don't buy it. Once you cut a person vertically in two half with a guillotine, you get two topological disks of skin. Each disk can be mapped into the 2D surface of the brain. It doesn't matter if the parts of the skin are in the same plane or rotated 90°.
Obviously some parts of the skin are stretched, so a 2D map will cause a lot of deformation. Also some parts of the skin are more sensitive than other and will need more brain surface. But this is what is happening, there are a few maps in the brain https://en.wikipedia.org/wiki/Cortical_homunculus and they are quite deformed, and they even have a few cuts here and there.
Once you decide to cut the map in two parts, each part can be projected in both orientations without geometric problems.
Maybe related, maybe not, but I noticed this quote is incorrect:
> Odd things happen when we [project 3D space onto a 2D surface]. On a 2D map, an airplane taking the most direct path between two cities appears to travel in an arc, and satellites orbiting the globe appear to oscillate in a sinusoidal path
If you use the Gnomonic projection then all great circles become straight lines.[0] The only "catch" is that you need to cut the Earth into two hemispheres.
Once you cut the person in two halves, it's easy to map the half to a plane.
Imagine a sphere. You cut it in two halves, and you get something like this https://en.wikipedia.org/wiki/Nicolosi_globular_projection and use a scissor to cut it in the middle. Now imagine the initial sphere is made of rubber and it contracts to a body glove thigh around the person.
There are no discontinuity inside each half. Just a huge discontinuity between the two halves, but each one is processed by a different side of the brain anyway.
The projections in each half can be made in both orientations, the one that is like the skin and the mirror one. The non-mirrored is difficult to wire, but the mirrored one is easy to wire.
About the discontinuity, there is a huge discontinuity between the two sides of your body that are processed by the two sides of your brain, and you don't notice it.
Moreover, in each eye, there is a discontinuity because each half of each of your eyes is proceed in a different side of your brain https://www.quora.com/Which-side-of-the-brain-does-the-optic... With that hardware I expect to see a black vertical line in the middle of my eyes, but the transition is quite smooth.
I don't find the TFA explanation convincing; it's too abstract.
I like the explanation in terms of predator avoidance behavior. Imagine a primitive fish with eyes that can detect motion. If it sees something moving, usually it wants to get away from that thing. If you see something moving in your left eye, the best way to swim away is to send a signal for a muscle contraction in your right side, which will cause you to curl and swim to the right. So the best wiring is a direct connection from left eye to right side, and right eye to left side. The brain is built up starting from that kind of connection.
But sensory input is also reversed. If you're touched on the right side of your body, it projects to the left side of your brain, which then projects back to the right side of your body again. If the goal were to minimize wire length, everything would stay on the right side.
> I don't find the TFA explanation convincing; it's too abstract.
...meaning you didn't understand it.
It may not be a good explanation, but the problem isn't that it's too abstract.
> If you see something moving in your left eye, the best way to swim away is to send a signal for a muscle contraction in your right side, which will cause you to curl and swim to the right. So the best wiring is a direct connection from left eye to right side, and right eye to left side. The brain is built up starting from that kind of connection.
If your fish only contracts the right side of it's body, that's not going to create effective motion, and while your fish is having the seizure you've described, it's going to get eaten.
Even if there were some sort of direct eye-to-muscle connection (which there isn't) the left eye would connect to the right side of the brain, which would then connect to the left side muscle, so you'd have left eye to left muscle (via the brain), not left eye to right muscle.
This is my take. With two sensors connected crosswise to musculature that pushes forward, you get goal seeking for targets in front and avoidant behaviour for targets behind.
> Letters on your T-shirt appear reversed for the same reason that the name “Quanta” would appear flipped, as “Quanta” if you wrote it with your finger on a frosty window and then went outside to look at it.
I'm amused at the audacity of the author for asking the webdevs to manually wire up a unique HTML span with a custom CSS transform solely to make a single word appear to be rendered as though seen in a mirror. :)
It's the inline style is in a hidden div at the end of the story and within #postbody, I suspect the author did it -- it's part of the story content at least -- and so didn't need the webdevs to do anything different. It's a nice touch.
Readit News
As a neurologist myself, I was taught it was specifically to simplify visual processing, although there may be other theories but this is what I was taught. Like others commenting here, the way the lens works in each eye is by flipping the image onto your retina. If we had only one eye, there would be no issue, the image would appear as a continuous image, just flipped around. However, because we have two eyes, they both individually flip different fields, thus separating the continuity of the image horizontally. If you try drawing out various different ways to try and remedy this problem of binocular vision, the way nature's approach is quite elegant in reuniting the image as well as separating visual processing into left/right.
To avoid a large text explanation, this is a simple diagram of the concept how the brain reforms the arrow. https://nba.uth.tmc.edu/neuroscience/s2/images/html5/s2_15_1...
The way it works is by separating the left and right fields of each eye, and then crossing them so that the left fields goes to the right half of the brain and the right fields go to the left half of the brain. Each right/left half is now interpreted by one side of the brain and the image is again continuous if you draw it out on the brain. Of course now each side of the brain sees the opposite side, but we remedy this by crossing everything else so it plays well with visual interpretation. Now the right side of the brain sees, senses, and controls the left side of the body and vice versa.
When it comes to everything else, there isn't a clear benefit for having processing swapped to opposite hemispheres. But visual processing benefits from it greatly, and so the rest of the nervous system goes along with it.
The problem you describe, of mapping binocular vision is an example of the topological problem described by the author. But it's not the only example: feeling nerves, for example, have the same symmetrical problem with mapping your skin sensations to the physical space, and your hearing also is "binocular" (there's actually a separate word for this, "binaural"). The visual problem you're describing is part of the topological problem. You're describing the same problem, but you're describing a part of the problem.
Where you're just wrong is on two points:
1. "When it comes to everything else, there isn't a clear benefit for having processing swapped to opposite hemispheres." Wrong. As mentioned before, binaural hearing also needs to map a 3d topology to a 2d topology from two data collection points, and skin needs to map a 3d topology from many more points (but also symmetrical). Additionally, the effect works on "outputs" as well as "inputs", mapping the 2d space to a 3d space so that you can control symmetrical tools such as your arms and legs means that the swapping is needed when sending signals outward as well.
2. "[V]isual processing benefits from it greatly, and so the rest of the nervous system goes along with it." Vision is not the evolutionary driver here. The criss-crossed neurology predates the existence of vision in our evolutionary heritage. The article mentions worms, for example: how does your hypothesis explain why their nerves crossed hemispherically given they don't have lenses and retinas?
Its just a general extrapolation of the same principle. It would also explain why creatures without sight as well like many worms.
This would require that worms evolved the cross crossing independently, after our common ancestor, which doesn’t seem to be clear [1].
All it would take is a few light receptors to get the cross cross party started.
[1] https://www.sciencedaily.com/releases/2010/02/100201101905.h...
PirB aka LILRB3 is also a protein involved in Alzheimers, toggling it affects neuroplasticity which includes vision.
https://www.nature.com/articles/nrn3616
creatures who have photoreceptors only, and not eyes, have this same swapping.
we don't know why this happens. period.
The article's explanation would explain all the facts we do know, so we can reasonably weight that as a very plausible explanation. I'll also add that the article says, 'Now, this all makes sense mathematically, but it’s important to note that we don’t know for certain that this is truly why our brains and bodies are connected the way they are. There is very little biological research on this intriguing question. The convenient dodge often heard is that the scientific method tells us “what,” not “why.”'
The GP's explanation doesn't explain why worms have criss-crossed nervous systems despite not having retinas or lenses, and it incorrectly assumes that other systems don't benefit from a criss-crossed nervous systems, so we can reasonably weight the GP's explanation as highly implausible.
why
If right side was connected right arm the nerves would be pressed “out”. When they cross there is less pressure in the spinal cord?
Neural connections on the left side are potentially protected from damage to the right side of the body and vice versa.
If the damage occurs to one side of the body but the brain is protected, would it not make for better chance of repair as the body heals?
Worms don't have retinas or lenses, but they have hemispherically crossed nervous systems.
I appreciate you trying to share your understanding though.
I had a sugar maple about 3 feet away from where I had to dig the foundation for the patio. An arborist said that it’s a bit close but the maple is strong and it should recover fine.
I cut out a bunch of roots and within a month the exact sections of the canopy corresponding to the roots I cut went brown.
It was incredible to me how the roots relate directly to the canopy. I always kinda thought it was one big circulatory system, where everything supports everything. I expected the whole tree to struggle a bit.
Next season the tree was fully recovered.
The neurological system seems to work the same way? It’s a directed graph where one root supports a very specific set of branches? I guess the circulatory system is like that too if you separate the two sets. Nature doesn’t really like cyclic graphs, does it?
Root systems in general (for trees at least) mirror what's happening above ground. Pruning trees is a beneficial intervention, as it causes the corresponding roots to die and decompose. This not only makes precious biomatter available for recycling by the microorganisms in the soil, but also releases chemical signals that cause the tree itself and neighbouring plants to send out new growth.
I had a course in computational neuroscience as part of my bachelor's and one of the things that we covered was that the timing of fires is important, in that depending on how soon before or after a neighbouring neuron fires, the connection may be weakened or strengthened. This is called Spike-timing-dependent plasticity:
> Under the STDP process, if an input spike to a neuron tends, on average, to occur immediately before that neuron's output spike, then that particular input is made somewhat stronger. If an input spike tends, on average, to occur immediately after an output spike, then that particular input is made somewhat weaker hence: "spike-timing-dependent plasticity"
From [1].
The implication of that, I believe, is that it prevents short cyclic graphs, for the sole reason of avoiding feedback loops that can cause the brain to go haywire (lol) due to the feedback loop. It sounds like an evolutionary adaptation to prevent short-circuiting.
From Hebbian Learning, we have that the cycles would become easier to trigger, meaning that it is a feedback loop that increases efficiency, however, without a mechanism to prevent this cyclical feedback loop, the brain could be filled with cycles that eventually turn to just rings, which is probably not a desirable property.
If anyone knows more about this please tell me. If it's a new idea, please remember to add my name :')
[1] https://en.wikipedia.org/wiki/Spike-timing-dependent_plastic...
https://www.frontiersin.org/articles/10.3389/fncom.2011.0002...
neurons change functional, and structural state, depending on past events [hysterisis] and will shut down/modify state activities depending on feedback from post synapic neurons.
also neurons will get tired and handoff activity to similar neurons in a cohort.
I have some news for you: https://en.wikipedia.org/wiki/Circle_of_Willis
neural convergence, and divergence, produce logic arrays that integrate many parameters to one integrated decision, vice versa
The issue described here is left-right symmetry, and it also applies to insects, so it is more general.
E.g.: someone else here was arguing that maybe the mirroring helps the brain keep processing inputs from the side that was hit. Evolution does not work this way! Flipping doesn’t “just” happen, that’s a huge morphological change. It had to have evolved incrementally, with each intermediate step having an immediate benefit.
The paper explains how and why this may have occurred.
In some primitive ancestor, it might have 'just' happened randomly. Some mutations that are small in genetic code terms can have huge effects on body structure.
That said, wonderful and simple result.
[0] https://en.wikipedia.org/wiki/Contralateral_brain#Twist_theo...
"To make sense of the sensation [...] your brain would have to switch from one somatotopic map to another one with the opposite z-axis orientation".
This a textbook example of the "Cartesian theater" fallacy. It assumes a little person inside the brain who has to deal with an image projected upside-down. Of course that doesn't make sense.
So you’re right about the little man. I struggle to see why some arbitrary axis transform is “too hard”.
[1] https://youtu.be/MFzDaBzBlL0
Obviously some parts of the skin are stretched, so a 2D map will cause a lot of deformation. Also some parts of the skin are more sensitive than other and will need more brain surface. But this is what is happening, there are a few maps in the brain https://en.wikipedia.org/wiki/Cortical_homunculus and they are quite deformed, and they even have a few cuts here and there.
Once you decide to cut the map in two parts, each part can be projected in both orientations without geometric problems.
> Odd things happen when we [project 3D space onto a 2D surface]. On a 2D map, an airplane taking the most direct path between two cities appears to travel in an arc, and satellites orbiting the globe appear to oscillate in a sinusoidal path
If you use the Gnomonic projection then all great circles become straight lines.[0] The only "catch" is that you need to cut the Earth into two hemispheres.
[0] https://en.wikipedia.org/wiki/Gnomonic_projection
Imagine a sphere. You cut it in two halves, and you get something like this https://en.wikipedia.org/wiki/Nicolosi_globular_projection and use a scissor to cut it in the middle. Now imagine the initial sphere is made of rubber and it contracts to a body glove thigh around the person.
There are no discontinuity inside each half. Just a huge discontinuity between the two halves, but each one is processed by a different side of the brain anyway.
The projections in each half can be made in both orientations, the one that is like the skin and the mirror one. The non-mirrored is difficult to wire, but the mirrored one is easy to wire.
About the discontinuity, there is a huge discontinuity between the two sides of your body that are processed by the two sides of your brain, and you don't notice it.
Moreover, in each eye, there is a discontinuity because each half of each of your eyes is proceed in a different side of your brain https://www.quora.com/Which-side-of-the-brain-does-the-optic... With that hardware I expect to see a black vertical line in the middle of my eyes, but the transition is quite smooth.
I like the explanation in terms of predator avoidance behavior. Imagine a primitive fish with eyes that can detect motion. If it sees something moving, usually it wants to get away from that thing. If you see something moving in your left eye, the best way to swim away is to send a signal for a muscle contraction in your right side, which will cause you to curl and swim to the right. So the best wiring is a direct connection from left eye to right side, and right eye to left side. The brain is built up starting from that kind of connection.
...meaning you didn't understand it.
It may not be a good explanation, but the problem isn't that it's too abstract.
> If you see something moving in your left eye, the best way to swim away is to send a signal for a muscle contraction in your right side, which will cause you to curl and swim to the right. So the best wiring is a direct connection from left eye to right side, and right eye to left side. The brain is built up starting from that kind of connection.
If your fish only contracts the right side of it's body, that's not going to create effective motion, and while your fish is having the seizure you've described, it's going to get eaten.
Even if there were some sort of direct eye-to-muscle connection (which there isn't) the left eye would connect to the right side of the brain, which would then connect to the left side muscle, so you'd have left eye to left muscle (via the brain), not left eye to right muscle.
...that's not what we have.
I'm amused at the audacity of the author for asking the webdevs to manually wire up a unique HTML span with a custom CSS transform solely to make a single word appear to be rendered as though seen in a mirror. :)