TIL that half the visual information from each retina goes to one hemisphere of the brain, rather than one eye per hemisphere
1d 1h ago by lemmy.world/u/Patnou in til from en.wikipedia.org
Fun semi-related fact:
Have you ever walked outside on a bright day and it's so bright it hurts? Turns out there's a max pain limit from brightness per eye, and your brain adds them together.
By closing one eye, you cut the total possible pain in half.
Or just look cool and sexy by squinting.
migraine time
Absolutely unfun semi-related fact:
Sometimes when one eye is injured, the injured eye has to be removed or your body will decide the uninjured eye is bad and your immune system will destroy it.
If the injured eye has no chance of recovery, they scoop it out.
Your body can also just decide it doesn't like a finger or limb and kill it.
Yeah, the immune system can be moronic. Intelligent design my ass.
However, there's something extra special about getting poked in one eye and having your own immune system decide that an eye for an eye means your good eye has to die.
that last bit is very satisfying to say
I think the immune system can't see the eye, so it's never trained to avoid it. If the eye is damaged, the immune system can become aware of it and start reacting. Once it starts, pulling it back is not easy.
The immune response system is simultaneously amazing and insane.
It basically deliberately scrambles part of the DNA in the immune cells that create antibodies. The rest of the body then sheds cells into the blood to move to the lymph nodes. Any immune cells that react then self destruct.
It's the equivalent of firing a paint blunderbuss at a wall, and creating a silhouette by standing in the way!
My immune system pisses me off constantly.
It let COVID through three times despite me rigorously keeping up to date with the vaccines as much as possible, and at the same time it has destroyed my thyroid gland and it has declared cherries and peaches as terrorist infiltrators.
I feel like if my immune system is so bored it needs to attack harmless things, I should never have to deal with any actually harmful thing.
It's like a cop that beats up an unarmed teenager, but hides when someone is shooting up a school.
Fuck sake! How else am I supposed to pick my nose?
You still have toes, ostensibly.
Oh cool
This explains why I have to close one eye to go outside in the sun lol
Huh, I've always closed one eye when it's super bright because it's simply more comfortable. Cool to have the behavior defined this way.
I never knew why the hell that worked, it seemed so bizarre and knowing it this way really is cool
That is fun, I’ve wondered why that is. I also think sometimes when it’s super bright out it makes me sneeze.
That's definitely a known thing.
My brain is weird, because if I'm super nauseous it makes me sneeze then I feel better
Photic sneeze response
Pretty sure it's related to the vagus nerve, maybe someone more knowledgeable can chime in.
Ok, John Denver! 🤪
Is this that odd? We experience less pain if one of two arms has a knife in it instead of both.
It is a bit odd. Your eyes feel pain to tell you whatever you are seeing might damage them if you look too long. But if you close one eye the pain can disappear entirely, even though that single eyes experience is the exact same.
Better to go blind in one eye. Then you can have a sweet eye patch
So it is averaged over both eyes. Do yoh experience any pain in one eye? Or is it always averaged over both?
Anybody else close one eye when it's too loud and they need to think?
Now it makes sense.
Less GPU usage by eyeballs, more capacity for prediction algorithms.
Same logic as turning down the radio when looking for a street.
I did notice that but I never even wondered why that is. Neat!
I met a person long ago that had one hemisphere "dead" after several strokes. So their vision was cut in half in a way I couldn't really understand before I found out about this.
So they could just see one side (left maybe) but with both eyes, like if you took a screenshot of a FPS view and completely cut off one half of the image
I literally just finished having a migraine aura (it's only the second time I've had one, though no headache the first time and no headache yet now.) I was reading a bit about it and how it's a caused by a slow wave going across one's brain. It started in the middle of my vision on the drive home, and after I arrived it continued sweeping off to my left field of vision until it dissipated off into the periphery a few minutes ago.
It's interesting to look at this image and imagine the wave going across the back of my right brain hemisphere. It's also interesting how even the visual looked like the cone-shaped wave that follows a sonic boom, slowly spreading out.
And now, with such dire imagery and the potential for upcoming pain, I'm going to lie down and hope nothing else happens.
Wish you a speedy post-drome. I had migraines for a year in the past, and the thought of going through that again fills me with dread.
The so-called "split brain" studies on people who have had the bridge between the two hemispheres - the corpus callosum - cut to treat grand mal seizures are fascinating. They use this method to communicate with each hemisphere separately without the other knowing.
You can, for example, give one an instruction to do something. After it has done it, you ask the other (verbal) hemisphere why they just did that, and they immediately make up a plausible-sounding explanation despite the scientists knowing it's not the actual reason.
You also get different answers for questions about dream jobs and such.
This all sparks the question: Are there two "people" in our brain the whole time or is the other created the moment the connection is cut? And which one is what I call "I"?
Inside of you are two brains: a dom and a sub.
You can, for example, give one an instruction to do something. After it has done it, you ask the other (verbal) hemisphere why they just did that, and they immediately make up a plausible-sounding explanation despite the scientists knowing it's not the actual reason.
Sounds like AI got something right then.
There's an uncomfortable amount of similarities between how the human brain and LLMs work.
Next word correlating with the words said before, confidently spreading false information, telling people what they want to hear.. These are by no means unique to LLMs.
2 people, that’s it? What if you are a voice machine, just voices all the way down… but you only recognize the loudest as yourself?
Fuck you very much for pointing to my brain like that ;)
I've seen this topic covered briefly in one of CGP Grey's videos. The video also gives a POV of a person with this syndrome. The POV was surprisingly interesting to watch and I was wondering if there are other similar recorded experiments.
You can, for example, give one an instruction to do something.
How would you do that? Since both eyes are connected to both hemispheres isn't it kind of hard to do that? Or are both ears separated and you can give commands through that without the other hemisphere knowing? I've heard about these studies too but I'm not sure about how the setup works because I've heard they used text on a screen for that but OP said the eyes do snitch to the other half after all. I find it a little confusing.
By building a setup that allows the researchers to flash text on the right/left visual field. On a normal brain this information does indeed travel between the hemispheres but on a split brain it doesn't.
what i want to know is whether making up an explanation is universal, or if other people would just go "no clue".
Because if EVERYONE with a severed corpus callosum just makes up explanations that is very fucking uncomfortable to think about, and i'll treasure having mine intact
I'm no neuroscientist but I don't think this has anything to do with the two hemispheres being separated - it's just how the human mind works. When something happens we come up with an explanation for it that's sometimes factual and sometimes completely made up. These people don't know that they're making it up - they genuinely believe the reason they're giving. We're not comfortable with uncertainty, especially when it comes to our own behavior.
I'm personally one of the people who doesn't believe in free will so these findings make perfect sense to me and are in no way in conflict with my worldview, but I get how hearing about this might make someone else uncomfortable.
That seems overly complex. Can we simplify this design?
That explains why one of my eyes turns off when I do loads of ket.
it specifically doesn't explain that
this you?
Isn't that the same thing?
i'm very curious how your brain works, did you look at the images in the article?
Well you see half of the images goes to one side of the brain...
One eye per hemisphere? Are you that one Hollywood exec who insists humans only use 1% of their brain?