2 ms·

Forgive my lack of knowledge of brain physiology, but is “cortex” a very small fraction of the total brain tissue? The common story is that our brains consume

by dahart 4y ago

Forgive my lack of knowledge of brain physiology, but is “cortex” a very small fraction of the total brain tissue? The common story is that our brains consume disproportionate amounts of energy compared to the rest of our body. So if both of these stories are true, it means the cortex for whatever reason is a very tiny portion of brain energy use, and the rest of the brain uses a lot more? * edit: Ah, I see the other story on the front page about brain comms using 35x more energy. So maybe the story with brains is the same as the story with computers - memory and transfers are the expensive part, and compute is surprisingly cheap.

SemanticStrengh 4y ago
The common story is that the brain consume 20% of the body energy. This study (if correct) refine the interpretation that the brain consume 20 watt by partitioning between computation and communication cost. Here there is no disproportionate amount of energy, it is just that the remainder is spent is mere communication. Also yes they speak about the cortex, it is true that the majority (~70%) of the neurons are not in the cortex but in the forgotten cerebellum, however while mysterious, the cerebellum is not necessary for language processing, there are some humans on earth that don't have a cerebellum and while less intelligent, rumors are that they are still human. Although this should be double checked. also while I think about it, there's probably a huge chunk (how much) of energy spent in building/catabolizing new axons vs executing the runtime.
andai 4y ago
There are cases of extreme hydrocephaly where 95% of brain matter was absent but the patient led a fairly normal life. I can't find the MRI image now but just imagine a thin, bright layer of brain tissue right against the skull, and almost total darkness (water) inside. Fair warning, you will see some pretty disturbing image results if you look it up.
- SemanticStrengh 4y ago
  you can find many here https://www.google.com/search?q=hydrocephalus+irm&sxsrf=ALiCzsal-78q5Y-Mg5ExMR_8UTO6bKJOwA:1652628571893&source=lnms&tbm=isch&sa=X&ved=2ahUKEwi6ruSX6eH3AhVMzIUKHWAaDncQ_AUoAXoECAEQAw&biw=1536&bih=713&dpr=2.5#imgrc=8ROdnmBvgjmP2M https://www.google.com/search?q=hydrocephalus+irm&sxsrf=ALiC... Look I have a hard time believing it. I mean yes those cases truly happened and the CBF fluid truly filled those zones. However my question is, can an IRM see beyong the a CBF fluid overload? Maybe there was just a shallow CBF overload and deep inside the neurons/synapses where still working. Or maybe not and those people really have lost 90% of their neurons, it's unfortunate no one care enough to fact check given this is essential towards understanding what is necessary in the brain.
- lostmsu 4y ago
  What about energy consumption? Are you sure 95% is by weight, not by volume?

by dahart 4y ago

SemanticStrengh 4y ago

The common story is that the brain consume 20% of the body energy. This study (if correct) refine the interpretation that the brain consume 20 watt by partitioning between computation and communication cost. Here there is no disproportionate amount of energy, it is just that the remainder is spent is mere communication. Also yes they speak about the cortex, it is true that the majority (~70%) of the neurons are not in the cortex but in the forgotten cerebellum, however while mysterious, the cerebellum is not necessary for language processing, there are some humans on earth that don't have a cerebellum and while less intelligent, rumors are that they are still human. Although this should be double checked. also while I think about it, there's probably a huge chunk (how much) of energy spent in building/catabolizing new axons vs executing the runtime.

andai 4y ago

There are cases of extreme hydrocephaly where 95% of brain matter was absent but the patient led a fairly normal life. I can't find the MRI image now but just imagine a thin, bright layer of brain tissue right against the skull, and almost total darkness (water) inside. Fair warning, you will see some pretty disturbing image results if you look it up.

SemanticStrengh 4y ago
you can find many here https://www.google.com/search?q=hydrocephalus+irm&sxsrf=ALiCzsal-78q5Y-Mg5ExMR_8UTO6bKJOwA:1652628571893&source=lnms&tbm=isch&sa=X&ved=2ahUKEwi6ruSX6eH3AhVMzIUKHWAaDncQ_AUoAXoECAEQAw&biw=1536&bih=713&dpr=2.5#imgrc=8ROdnmBvgjmP2M https://www.google.com/search?q=hydrocephalus+irm&sxsrf=ALiC... Look I have a hard time believing it. I mean yes those cases truly happened and the CBF fluid truly filled those zones. However my question is, can an IRM see beyong the a CBF fluid overload? Maybe there was just a shallow CBF overload and deep inside the neurons/synapses where still working. Or maybe not and those people really have lost 90% of their neurons, it's unfortunate no one care enough to fact check given this is essential towards understanding what is necessary in the brain.
lostmsu 4y ago
What about energy consumption? Are you sure 95% is by weight, not by volume?