5 ms·

Very few people know the potent facts about the brain: * your neurons are not in your "brain" 90% of your neurons are not in what you generally denote by brain

Very few people know the potent facts about the brain: * your neurons are not in your "brain" 90% of your neurons are not in what you generally denote by brain. They are in your cerebellum. The cerebellum has a distinct neural architecture, that difference is in fact clearly visible with the najed eye. A very poor simplistification would be to call it our GPU. * the spinal cord is huge and is structurally a contiguous extension of your brain. * your brain is mostly not filled with blood but with the transparent cerebrospinal fluid Btw there is a liquid almost twice as much more present in the human body than blood, the white lymph. It's unclear to me why we don't see lymph on dissected bodies. (possibly because of microvascularisation?) also anyone know how is lymph pumped? I don't think the heart pump lymph so is it stagnant? * opiods,nicotine, and cannabinoids are endogenous neuroreceptors. They have the name of exogenous drugs because it happens they bind on those ligands but that also means that the brain generate similar but slightly different analogues itself. * in terms of neurotransmitter s, types of receptors and even patterns of activation of brain regions per stimulus, humans are not much different from rats or other mammals and this apply for surprisingly high levels cognitive tasks such as e.g ADHD. * the problem of consciousness/qualias If qualias are supraphysical then how can it be created from a physical process? Moreover where are you?! Where are you qualias located in your brain? And more remarquably, how many are you? Our two hemispheres are highly (but not that much though) symmetric, we might have one consciousness per hemisphere. Or not? But then what about those people that have their hemispheres crosstalk surgically cut? They behave normally (mostly), and have two independent brains. However the best proof might be e.g dolphins, which have a mono-hemispheric alternating sleep. So if one hemisphere dream, the other day it's the other hemisphere. Hence two distinct qualiesque brain in one dolphin brain.

sph 5y ago
> your neurons are not in your "brain" 90% of your neurons are not in what you generally denote by brain. They are in your cerebellum. Excuse the dumb question, but what's in the brain then? Or are you meaning to say that the cerebellum has a much higher density of neurons than the brain?
- SemanticStrengh 5y ago
  Well clearly it means the "brain" (the cerebrum) contains less than the remaining 10% neurons https://www.cancer.gov/publications/dictionaries/cancer-terms/def/cerebrum https://www.cancer.gov/publications/dictionaries/cancer-term... Shared with the midbrain and spinal cord. Of course I am excluding PNS neurons
d4mi3n 5y ago
> also anyone know how is lymph pumped? I don't think the heart pump lymph so is it stagnant? I have a close friend who is working on getting certified as a massage therapist. Skeletal, muscular, and vascular anatomy make up a big part of the required knowledge for the certification. Two interesting things I learned from them: 1. The lymphatic system is massive and runs alongside our vascular system. For example, there are many lymphatic veins that run through the head and face that empty out just near our clavicle, where they’re the picked up by large vascular veins to the heart, and then on to the liver for filtration. 2. The lymph system is not attached to our heat, and movement of fluid in those veins is purely driven by mechanical motion of our bodies. This is often why paraplegics or folks with other forms of paralysis end up with swollen feet—lymphatic fluid gets trapped in the extremities and collects whoever gravity dictates. Fascinating stuff. Gave me a much greater appreciation for the level of knowledge and skill to be a massage therapist.
- SemanticStrengh 5y ago
  Wow I wonder how much power does gravity has over lymph repartition in the body? I mean wether I lay down or stand still probably impact the "coverage" of our body by the immune system. There might be correlates between time to recovery and human position and movements then. BTW bugs do not have vascularisation their body is one single flask of stagnant fluid. And their brain is distributed..
  - d4mi3n 5y ago
    Fun fact: one of the red flag symptoms of a headache or migraine is if it is significantly less severe sitting up vs lying down. Or if it gets worse when you sneeze. I am NOT a doctor, but IIRC this can be a signal of serious issues they could be causing such a headache, as it means the blood pressure caused by lying down or sneezing is potentially stressing vascular structure in your head. See: https://youtu.be/d2vW_CHWqo4 https://youtu.be/d2vW_CHWqo4
- iamacyborg 5y ago
  A thing I find interesting is that autopsies are finding that folks with tattoos end up with stained lymph nodes as the tattoo ink gets spread through the lymphatic system. As tattoos have become hugely popular in the last couple decades I wonder if we’ll start seeing more health problems associated with the chemicals used in inks.
andbberger 5y ago
this is a terrible list of 'brain facts'. they're not interesting or constructive to a larger understanding, and analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. working neuroscientist don't think about consciousness, we look at neurobiology, develop experimental techniques to allow imaging of ever larger numbers of neurons, try to understand how the brain computes. I don't see how one could boil down the staggering complexity of the field in the one-bite popsci factoids that leave a layperson with any useful model of the brain. People certainly try though (ahem, Andrew Huberman...). Here are some facts though: you have some neurons, they do things sometimes. we have some vague ideas about what different bits of brain do in very specific context. we have absolutely no idea how it all fits together, and are decades away from such an understanding. the fruit fly visual cortex, which is several orders of magnitude smaller than mammalian cortex, has been exhaustively studied for 40+ years, and we are only recently starting to build a circuit level model of the computation in the first layers. Here is your fact: brains are the most complex objects in the known universe
- SemanticStrengh 5y ago
  What an absurd dismissal. > they're not interesting You have a failure of appreciation, yet those facts are potent and surprising. >constructive to a larger understanding Yes they are not, who cares? Teaching neuroscience is of course a non-goal of my comment, what an irrelevant thing to say.. >analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. Exactly, but if you had allocated a few neurons while reading my comment you would have seen I said "a poor simplist-ification" akin to only transmitting the idea that it is the place in the brain with the most compute power/parallelism. >working neuroscientist don't think about consciousness, we look at neurobiology, Such a useless thing to say. It is a truism that scientists mostly focus on what can be studied by the means of metrology/empiricism and indeed for now, qualias are low-studiable. Saying this has no more value than saying water is wet. Your shallow dismissal is just a pretext to your layman explanation of what is the brain. Explanation with btw zero level of detail. I have read over 1000 papers in neuropharmacology and there are in facts a lot of things we understand about brains. But, the C.elegans ~150-300 neurons, which is much simpler than the fruit flies, is as of now unexplained in terms of neural code, despite having an almost complete connectome of its neuroreceptors. But no the C.elgans is not one of the most complex thing in the universe. This is a fallacy that make seems progress seems impossible. The truth is, C.elgans has a relatively reasonable complexity, however we lack real-time datasets and we lack accurate instruments to observe and retroengineer the while system.
elric 5y ago
Fun fact: the brain also has a lymphatic system, which wasn't described until about ten years ago. It's called the glymphatic system, and apparently it was rather difficult to spot.
femto 5y ago
The brain's lymphatic system was confirmed to exist only recently, in 2017. https://www.theatlantic.com/health/archive/2017/10/scientists-somehow-just-discovered-a-new-system-of-vessels-in-our-brains/542037/ https://www.theatlantic.com/health/archive/2017/10/scientist... https://www.sciencedaily.com/releases/2019/07/190724133649.htm https://www.sciencedaily.com/releases/2019/07/190724133649.h...
agumonkey 5y ago
I have a vested interest in very precise understanding of brain structures (qualia too but less pressing matter). In particular: - visual perception of self - visual perception of others and the somatosensory aspect of those points, how do i represent your emotions and body in my head, my own body / image / emotions too; and how do they relate. if that means anything to anybody, comment down. Thanks in advance
leemailll 5y ago
I don't know where you get the idea brain does not include cerebellum. This is completely false
- SemanticStrengh 5y ago
  Re-read my sentence, yes the cerebellum is part of the CNS and so is the spinal cord. Is the spinal cord part of the brain? Why not. What I meant is what people generally denote and imagine when we speak about the brain, is actually the cerebrum https://www.cancer.gov/publications/dictionaries/cancer-terms/def/cerebrum https://www.cancer.gov/publications/dictionaries/cancer-term... The cerebellum, pons, etc are distinct extensions.
  - kaba0 5y ago
    The brain/spinal coord is commonly divided at the start of the brain stem. By all accounts, the cerebellum is part of the brain.
    - SemanticStrengh 5y ago
      It is part of the brain but not in the mind of the layman which is what I meant. If you asked to someone wether the vast majority of our neurons are located in the cerebrum (not the cerebellum) they would say "of course".

sph 5y ago

> your neurons are not in your "brain" 90% of your neurons are not in what you generally denote by brain. They are in your cerebellum. Excuse the dumb question, but what's in the brain then? Or are you meaning to say that the cerebellum has a much higher density of neurons than the brain?

SemanticStrengh 5y ago
Well clearly it means the "brain" (the cerebrum) contains less than the remaining 10% neurons https://www.cancer.gov/publications/dictionaries/cancer-terms/def/cerebrum https://www.cancer.gov/publications/dictionaries/cancer-term... Shared with the midbrain and spinal cord. Of course I am excluding PNS neurons

d4mi3n 5y ago

> also anyone know how is lymph pumped? I don't think the heart pump lymph so is it stagnant? I have a close friend who is working on getting certified as a massage therapist. Skeletal, muscular, and vascular anatomy make up a big part of the required knowledge for the certification. Two interesting things I learned from them: 1. The lymphatic system is massive and runs alongside our vascular system. For example, there are many lymphatic veins that run through the head and face that empty out just near our clavicle, where they’re the picked up by large vascular veins to the heart, and then on to the liver for filtration. 2. The lymph system is not attached to our heat, and movement of fluid in those veins is purely driven by mechanical motion of our bodies. This is often why paraplegics or folks with other forms of paralysis end up with swollen feet—lymphatic fluid gets trapped in the extremities and collects whoever gravity dictates. Fascinating stuff. Gave me a much greater appreciation for the level of knowledge and skill to be a massage therapist.

SemanticStrengh 5y ago
Wow I wonder how much power does gravity has over lymph repartition in the body? I mean wether I lay down or stand still probably impact the "coverage" of our body by the immune system. There might be correlates between time to recovery and human position and movements then. BTW bugs do not have vascularisation their body is one single flask of stagnant fluid. And their brain is distributed..
- d4mi3n 5y ago
  Fun fact: one of the red flag symptoms of a headache or migraine is if it is significantly less severe sitting up vs lying down. Or if it gets worse when you sneeze. I am NOT a doctor, but IIRC this can be a signal of serious issues they could be causing such a headache, as it means the blood pressure caused by lying down or sneezing is potentially stressing vascular structure in your head. See: https://youtu.be/d2vW_CHWqo4 https://youtu.be/d2vW_CHWqo4
iamacyborg 5y ago
A thing I find interesting is that autopsies are finding that folks with tattoos end up with stained lymph nodes as the tattoo ink gets spread through the lymphatic system. As tattoos have become hugely popular in the last couple decades I wonder if we’ll start seeing more health problems associated with the chemicals used in inks.

andbberger 5y ago

this is a terrible list of 'brain facts'. they're not interesting or constructive to a larger understanding, and analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. working neuroscientist don't think about consciousness, we look at neurobiology, develop experimental techniques to allow imaging of ever larger numbers of neurons, try to understand how the brain computes. I don't see how one could boil down the staggering complexity of the field in the one-bite popsci factoids that leave a layperson with any useful model of the brain. People certainly try though (ahem, Andrew Huberman...). Here are some facts though: you have some neurons, they do things sometimes. we have some vague ideas about what different bits of brain do in very specific context. we have absolutely no idea how it all fits together, and are decades away from such an understanding. the fruit fly visual cortex, which is several orders of magnitude smaller than mammalian cortex, has been exhaustively studied for 40+ years, and we are only recently starting to build a circuit level model of the computation in the first layers. Here is your fact: brains are the most complex objects in the known universe

SemanticStrengh 5y ago
What an absurd dismissal. > they're not interesting You have a failure of appreciation, yet those facts are potent and surprising. >constructive to a larger understanding Yes they are not, who cares? Teaching neuroscience is of course a non-goal of my comment, what an irrelevant thing to say.. >analogizing the cerebellum to a GPU is naive and misleading to the point of being insulting. Exactly, but if you had allocated a few neurons while reading my comment you would have seen I said "a poor simplist-ification" akin to only transmitting the idea that it is the place in the brain with the most compute power/parallelism. >working neuroscientist don't think about consciousness, we look at neurobiology, Such a useless thing to say. It is a truism that scientists mostly focus on what can be studied by the means of metrology/empiricism and indeed for now, qualias are low-studiable. Saying this has no more value than saying water is wet. Your shallow dismissal is just a pretext to your layman explanation of what is the brain. Explanation with btw zero level of detail. I have read over 1000 papers in neuropharmacology and there are in facts a lot of things we understand about brains. But, the C.elegans ~150-300 neurons, which is much simpler than the fruit flies, is as of now unexplained in terms of neural code, despite having an almost complete connectome of its neuroreceptors. But no the C.elgans is not one of the most complex thing in the universe. This is a fallacy that make seems progress seems impossible. The truth is, C.elgans has a relatively reasonable complexity, however we lack real-time datasets and we lack accurate instruments to observe and retroengineer the while system.

elric 5y ago

Fun fact: the brain also has a lymphatic system, which wasn't described until about ten years ago. It's called the glymphatic system, and apparently it was rather difficult to spot.

femto 5y ago

The brain's lymphatic system was confirmed to exist only recently, in 2017. https://www.theatlantic.com/health/archive/2017/10/scientists-somehow-just-discovered-a-new-system-of-vessels-in-our-brains/542037/ https://www.theatlantic.com/health/archive/2017/10/scientist... https://www.sciencedaily.com/releases/2019/07/190724133649.htm https://www.sciencedaily.com/releases/2019/07/190724133649.h...

agumonkey 5y ago

I have a vested interest in very precise understanding of brain structures (qualia too but less pressing matter). In particular: - visual perception of self - visual perception of others and the somatosensory aspect of those points, how do i represent your emotions and body in my head, my own body / image / emotions too; and how do they relate. if that means anything to anybody, comment down. Thanks in advance

leemailll 5y ago

I don't know where you get the idea brain does not include cerebellum. This is completely false

SemanticStrengh 5y ago
Re-read my sentence, yes the cerebellum is part of the CNS and so is the spinal cord. Is the spinal cord part of the brain? Why not. What I meant is what people generally denote and imagine when we speak about the brain, is actually the cerebrum https://www.cancer.gov/publications/dictionaries/cancer-terms/def/cerebrum https://www.cancer.gov/publications/dictionaries/cancer-term... The cerebellum, pons, etc are distinct extensions.
- kaba0 5y ago
  The brain/spinal coord is commonly divided at the start of the brain stem. By all accounts, the cerebellum is part of the brain.
  - SemanticStrengh 5y ago
    It is part of the brain but not in the mind of the layman which is what I meant. If you asked to someone wether the vast majority of our neurons are located in the cerebrum (not the cerebellum) they would say "of course".