Cells use 'bioelectricity' to coordinate and make group decisions
marojejian
Even since reading about Michael Levin's work, I've been sold that there is a lot going on in terms of bioelectricity outside of neurons. But I haven't seen that much progress. This is one interesting, albeit simple example.
>In this way, bioelectrical flow across cell membranes lets tissues test which cells are the least healthy and mark them for extrusion. “They’re always pushing against each other and bullying each other. And what they’re doing is probing each other for which one’s the weakest link,” Rosenblatt said. “It’s a community effect.”
This fits with my model of how high levels of cooperation succeed in biology. Even in a community as homogeneous as cells you have the risk of defectors (cancer), or just poor members. As such you need a process to continually test your community members.
FranklinJabar
Why not simply say electricity?
ggm
You're rght. Light? thats just EMF. Infra Red? Emf. Xrays? It's all EMF man.
At least thats ITU regulated frequency bands. I wonder if the ITU regulates biogenic DC signalling frequencies?
skyberrys
The article notes that bioelectricity is just referring to electricity not occuring in the heart or brain which has a different specialized name. Simply saying electricity is captures more than the cell types reported on.
nosianu
Because that is useless? The physical phenomenon is so very, very different in biological systems compared to the metal-wire electricity our electrical devices are based on that they are entirely different things.
For example, charge carriers are electrons in metal wires vs. ions in biological systems. That has huge implications, because moving around ions is a lot harder, and slower.
In a metal wire the electrical field is established from beginning to the end, and that means that the electrons at the end start moving at pretty much the same time as the ones at the other end, no matter how long the wire. That means in a metal wire signals move at a significant fraction of the speed of light in a vacuum, because it is the speed of the electrical field and not that of the charge carriers that matters.
In a biological system electrical fields are tiny! The way the signal propagates in an axon is much more cumbersome, expensive, and slow. Speed of signal propagation is ca. 1/2 to at most 100 m/s (for thick myelinated axons). The signal is propagated by jumping in very tiny steps along the axon's inner surface. (https://youtu.be/tOTYO5WrXFU)
This also makes The Matrix movies' main premise about humans as batteries a little strange: Sure, there's lots of electrical activity, but it is in trillions of very tiny places across nanometer distances. And it is created by moving ions around (at great energy cost).
So anyway, what actually physically happens in an electrical grid of metal wires, or in a biological system are vastly different things. It is not the same "electricity", the only thing they have in common is that electrical fields and charge carriers (but different ones) are involved. But the way it is structured, created, propagated is entirely different in both cases.
bitwize
Yes, but how do they handle Byzantine fault tolerance?
taneq
T-cells. :P
jeffybefffy519
Could this lead into how there are people who thing non ionising radiation sources affect them?
nandomrumber
One acquaintance, after years of trying to work out what was wrong and believing EM missions may play a role turned out to have hemochromotosis (genetic disorder characterized by excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron) which is fixed by regular blood donations.
Torkel
Here's a study from 2023 where they apply external electricity to improve healing rate of wounds:
It enabled healing of diabetic wounds that are otherwise hard to heal.
inshard
Michael Levine really opened my mind to phase space in biology.
mjanx123
Electricity is the core of a single cell functionality as well, most biomolecules are on the exact boundary between a conductor and an insulator (and likely switch the state based on other molecules binding, pH, etc). A group of cells electricity is a higher level abstraction of that.
makes me wonder what effect a low current flowing through the body would have on this process. would it hinder/disrupt this coordination?
xg15
The article describes the mechanism in some detail near the end. As I understand it, it's not really "coordination" in the sense that they exchange messages through the electricity.
It's more that every cell has to maintain a voltage difference between the inside and outside ("membrane potential"). A healthy cell does that constantly using "ion pumps" that use chemical energy (ATP) to increase the potential.
If that potential falls below a certain threshold, certain molecular mechanisms (voltage-sensitive ion channels) inside the cell are triggered that lead to ejection.
Interestingly, are also other mechanisms (pressure-sensitive ion channels) that will "intentionally" make it harder for a cell to maintain its potential if it's already weakened or if the surrounding region is very crowded.
As such, I think the effect of current would depend on the way how it would change the voltage differences of the individual cells.
nprateem
It'll blow their minds when they start researching chi kung and realise it's possible to draw in more energy by breathing and move it round the body. It's also possible to feel some kind of field around the body.
Auras and chakras don't sound so silly now do they.
Terr_
"It'll blow those Chemists' minds when they start researching Alchemy and they realize the incredible power of mercury and lead to rejuvenate the body and lead to an elixir of youth!"
"It'll blow those Astronomers' minds when they start researching Astrology and the powerful effect of being born under auspicious constellations!"
__________
If the ancient guru knowledge is so great, what testable predictions does it offer, where "auras" are a causal mechanism?
In other words, not: "Thou must intake the golden aura of oats and fiber by eating some, to counter the dark brown blockage of your Pu-point." The folk remedy might well solve your constipation, but it wouldn't be evidence for the mythology around it.
renewiltord
Lol no, this crank shit sounds dumb as fuck haha. Kamehameha!
ben_w
> possible to draw in more energy by breathing and move it round the body
We already know what haemoglobin is thanks
jupiterelastica
For those interested in more details and quite mind blowing examples, here is a fascinating interview with Michael Levin (one of the researchers mentioned in the article).
Start at 1:19:11, the stuff before is him talking about biology, but from an intelligence perspective. After this time stamp is his retrospective on his bioelectricity research over the years, showing also examples of how they got a frog embryo to produce eyes, and many more things.
joel_liu
Thanks for sharing this timestamp - Levin's retrospective on bioelectricity research is compelling. What fascinates me most is how his work challenges the gene-centric view of development. The experiments showing bioelectric patterns can override genetic instructions (like inducing eye formation in non-eye tissue) reveal a whole layer of morphogenetic information we're just beginning to understand.
zkmon
It was known for a long time that some reflexes and responses are mostly spontaneous and don't require decisions from the mind. Such reactions, such as pulling away when touched a hot surface, do require muscle contraction which in turn requires electrical pulses, which indicates the presence of bio electrical charges everywhere. Can some help me understand what exactly is new here. I knew that something is new.
Angostura
What you are talking about is the functional use of electrical impulses to active muscle. This article is talking about electrical potential as signalling mechanism for cell health, than can be used by a tissue to eject aging or sick cells
Even since reading about Michael Levin's work, I've been sold that there is a lot going on in terms of bioelectricity outside of neurons. But I haven't seen that much progress. This is one interesting, albeit simple example.
>In this way, bioelectrical flow across cell membranes lets tissues test which cells are the least healthy and mark them for extrusion. “They’re always pushing against each other and bullying each other. And what they’re doing is probing each other for which one’s the weakest link,” Rosenblatt said. “It’s a community effect.”
This fits with my model of how high levels of cooperation succeed in biology. Even in a community as homogeneous as cells you have the risk of defectors (cancer), or just poor members. As such you need a process to continually test your community members.
FranklinJabar
Why not simply say electricity?
ggm
You're rght. Light? thats just EMF. Infra Red? Emf. Xrays? It's all EMF man.
At least thats ITU regulated frequency bands. I wonder if the ITU regulates biogenic DC signalling frequencies?
skyberrys
The article notes that bioelectricity is just referring to electricity not occuring in the heart or brain which has a different specialized name. Simply saying electricity is captures more than the cell types reported on.
nosianu
Because that is useless? The physical phenomenon is so very, very different in biological systems compared to the metal-wire electricity our electrical devices are based on that they are entirely different things.
For example, charge carriers are electrons in metal wires vs. ions in biological systems. That has huge implications, because moving around ions is a lot harder, and slower.
In a metal wire the electrical field is established from beginning to the end, and that means that the electrons at the end start moving at pretty much the same time as the ones at the other end, no matter how long the wire. That means in a metal wire signals move at a significant fraction of the speed of light in a vacuum, because it is the speed of the electrical field and not that of the charge carriers that matters.
In a biological system electrical fields are tiny! The way the signal propagates in an axon is much more cumbersome, expensive, and slow. Speed of signal propagation is ca. 1/2 to at most 100 m/s (for thick myelinated axons). The signal is propagated by jumping in very tiny steps along the axon's inner surface. (https://youtu.be/tOTYO5WrXFU)
This also makes The Matrix movies' main premise about humans as batteries a little strange: Sure, there's lots of electrical activity, but it is in trillions of very tiny places across nanometer distances. And it is created by moving ions around (at great energy cost).
So anyway, what actually physically happens in an electrical grid of metal wires, or in a biological system are vastly different things. It is not the same "electricity", the only thing they have in common is that electrical fields and charge carriers (but different ones) are involved. But the way it is structured, created, propagated is entirely different in both cases.
bitwize
Yes, but how do they handle Byzantine fault tolerance?
taneq
T-cells. :P
jeffybefffy519
Could this lead into how there are people who thing non ionising radiation sources affect them?
nandomrumber
One acquaintance, after years of trying to work out what was wrong and believing EM missions may play a role turned out to have hemochromotosis (genetic disorder characterized by excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron) which is fixed by regular blood donations.
Torkel
Here's a study from 2023 where they apply external electricity to improve healing rate of wounds:
It enabled healing of diabetic wounds that are otherwise hard to heal.
inshard
Michael Levine really opened my mind to phase space in biology.
mjanx123
Electricity is the core of a single cell functionality as well, most biomolecules are on the exact boundary between a conductor and an insulator (and likely switch the state based on other molecules binding, pH, etc). A group of cells electricity is a higher level abstraction of that.
makes me wonder what effect a low current flowing through the body would have on this process. would it hinder/disrupt this coordination?
xg15
The article describes the mechanism in some detail near the end. As I understand it, it's not really "coordination" in the sense that they exchange messages through the electricity.
It's more that every cell has to maintain a voltage difference between the inside and outside ("membrane potential"). A healthy cell does that constantly using "ion pumps" that use chemical energy (ATP) to increase the potential.
If that potential falls below a certain threshold, certain molecular mechanisms (voltage-sensitive ion channels) inside the cell are triggered that lead to ejection.
Interestingly, are also other mechanisms (pressure-sensitive ion channels) that will "intentionally" make it harder for a cell to maintain its potential if it's already weakened or if the surrounding region is very crowded.
As such, I think the effect of current would depend on the way how it would change the voltage differences of the individual cells.
nprateem
It'll blow their minds when they start researching chi kung and realise it's possible to draw in more energy by breathing and move it round the body. It's also possible to feel some kind of field around the body.
Auras and chakras don't sound so silly now do they.
Terr_
"It'll blow those Chemists' minds when they start researching Alchemy and they realize the incredible power of mercury and lead to rejuvenate the body and lead to an elixir of youth!"
"It'll blow those Astronomers' minds when they start researching Astrology and the powerful effect of being born under auspicious constellations!"
__________
If the ancient guru knowledge is so great, what testable predictions does it offer, where "auras" are a causal mechanism?
In other words, not: "Thou must intake the golden aura of oats and fiber by eating some, to counter the dark brown blockage of your Pu-point." The folk remedy might well solve your constipation, but it wouldn't be evidence for the mythology around it.
renewiltord
Lol no, this crank shit sounds dumb as fuck haha. Kamehameha!
ben_w
> possible to draw in more energy by breathing and move it round the body
We already know what haemoglobin is thanks
jupiterelastica
For those interested in more details and quite mind blowing examples, here is a fascinating interview with Michael Levin (one of the researchers mentioned in the article).
Start at 1:19:11, the stuff before is him talking about biology, but from an intelligence perspective. After this time stamp is his retrospective on his bioelectricity research over the years, showing also examples of how they got a frog embryo to produce eyes, and many more things.
joel_liu
Thanks for sharing this timestamp - Levin's retrospective on bioelectricity research is compelling. What fascinates me most is how his work challenges the gene-centric view of development. The experiments showing bioelectric patterns can override genetic instructions (like inducing eye formation in non-eye tissue) reveal a whole layer of morphogenetic information we're just beginning to understand.
zkmon
It was known for a long time that some reflexes and responses are mostly spontaneous and don't require decisions from the mind. Such reactions, such as pulling away when touched a hot surface, do require muscle contraction which in turn requires electrical pulses, which indicates the presence of bio electrical charges everywhere. Can some help me understand what exactly is new here. I knew that something is new.
Angostura
What you are talking about is the functional use of electrical impulses to active muscle. This article is talking about electrical potential as signalling mechanism for cell health, than can be used by a tissue to eject aging or sick cells
Even since reading about Michael Levin's work, I've been sold that there is a lot going on in terms of bioelectricity outside of neurons. But I haven't seen that much progress. This is one interesting, albeit simple example.
>In this way, bioelectrical flow across cell membranes lets tissues test which cells are the least healthy and mark them for extrusion. “They’re always pushing against each other and bullying each other. And what they’re doing is probing each other for which one’s the weakest link,” Rosenblatt said. “It’s a community effect.”
This fits with my model of how high levels of cooperation succeed in biology. Even in a community as homogeneous as cells you have the risk of defectors (cancer), or just poor members. As such you need a process to continually test your community members.
Why not simply say electricity?
You're rght. Light? thats just EMF. Infra Red? Emf. Xrays? It's all EMF man.
At least thats ITU regulated frequency bands. I wonder if the ITU regulates biogenic DC signalling frequencies?
The article notes that bioelectricity is just referring to electricity not occuring in the heart or brain which has a different specialized name. Simply saying electricity is captures more than the cell types reported on.
Because that is useless? The physical phenomenon is so very, very different in biological systems compared to the metal-wire electricity our electrical devices are based on that they are entirely different things.
For example, charge carriers are electrons in metal wires vs. ions in biological systems. That has huge implications, because moving around ions is a lot harder, and slower.
In a metal wire the electrical field is established from beginning to the end, and that means that the electrons at the end start moving at pretty much the same time as the ones at the other end, no matter how long the wire. That means in a metal wire signals move at a significant fraction of the speed of light in a vacuum, because it is the speed of the electrical field and not that of the charge carriers that matters.
In a biological system electrical fields are tiny! The way the signal propagates in an axon is much more cumbersome, expensive, and slow. Speed of signal propagation is ca. 1/2 to at most 100 m/s (for thick myelinated axons). The signal is propagated by jumping in very tiny steps along the axon's inner surface. (https://youtu.be/tOTYO5WrXFU)
This also makes The Matrix movies' main premise about humans as batteries a little strange: Sure, there's lots of electrical activity, but it is in trillions of very tiny places across nanometer distances. And it is created by moving ions around (at great energy cost).
So anyway, what actually physically happens in an electrical grid of metal wires, or in a biological system are vastly different things. It is not the same "electricity", the only thing they have in common is that electrical fields and charge carriers (but different ones) are involved. But the way it is structured, created, propagated is entirely different in both cases.
Yes, but how do they handle Byzantine fault tolerance?
T-cells. :P
Could this lead into how there are people who thing non ionising radiation sources affect them?
One acquaintance, after years of trying to work out what was wrong and believing EM missions may play a role turned out to have hemochromotosis (genetic disorder characterized by excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron) which is fixed by regular blood donations.
Here's a study from 2023 where they apply external electricity to improve healing rate of wounds:
https://pubs.rsc.org/en/content/articlelanding/2023/LC/D2LC0...
It enabled healing of diabetic wounds that are otherwise hard to heal.
Michael Levine really opened my mind to phase space in biology.
Electricity is the core of a single cell functionality as well, most biomolecules are on the exact boundary between a conductor and an insulator (and likely switch the state based on other molecules binding, pH, etc). A group of cells electricity is a higher level abstraction of that.
https://medium.com/the-physics-arxiv-blog/the-origin-of-life...
makes me wonder what effect a low current flowing through the body would have on this process. would it hinder/disrupt this coordination?
The article describes the mechanism in some detail near the end. As I understand it, it's not really "coordination" in the sense that they exchange messages through the electricity.
It's more that every cell has to maintain a voltage difference between the inside and outside ("membrane potential"). A healthy cell does that constantly using "ion pumps" that use chemical energy (ATP) to increase the potential.
If that potential falls below a certain threshold, certain molecular mechanisms (voltage-sensitive ion channels) inside the cell are triggered that lead to ejection.
Interestingly, are also other mechanisms (pressure-sensitive ion channels) that will "intentionally" make it harder for a cell to maintain its potential if it's already weakened or if the surrounding region is very crowded.
As such, I think the effect of current would depend on the way how it would change the voltage differences of the individual cells.
It'll blow their minds when they start researching chi kung and realise it's possible to draw in more energy by breathing and move it round the body. It's also possible to feel some kind of field around the body.
Auras and chakras don't sound so silly now do they.
"It'll blow those Chemists' minds when they start researching Alchemy and they realize the incredible power of mercury and lead to rejuvenate the body and lead to an elixir of youth!"
"It'll blow those Astronomers' minds when they start researching Astrology and the powerful effect of being born under auspicious constellations!"
__________
If the ancient guru knowledge is so great, what testable predictions does it offer, where "auras" are a causal mechanism?
In other words, not: "Thou must intake the golden aura of oats and fiber by eating some, to counter the dark brown blockage of your Pu-point." The folk remedy might well solve your constipation, but it wouldn't be evidence for the mythology around it.
Lol no, this crank shit sounds dumb as fuck haha. Kamehameha!
> possible to draw in more energy by breathing and move it round the body
We already know what haemoglobin is thanks
For those interested in more details and quite mind blowing examples, here is a fascinating interview with Michael Levin (one of the researchers mentioned in the article).
https://youtu.be/c8iFtaltX-s?t=4751
Start at 1:19:11, the stuff before is him talking about biology, but from an intelligence perspective. After this time stamp is his retrospective on his bioelectricity research over the years, showing also examples of how they got a frog embryo to produce eyes, and many more things.
Thanks for sharing this timestamp - Levin's retrospective on bioelectricity research is compelling. What fascinates me most is how his work challenges the gene-centric view of development. The experiments showing bioelectric patterns can override genetic instructions (like inducing eye formation in non-eye tissue) reveal a whole layer of morphogenetic information we're just beginning to understand.
It was known for a long time that some reflexes and responses are mostly spontaneous and don't require decisions from the mind. Such reactions, such as pulling away when touched a hot surface, do require muscle contraction which in turn requires electrical pulses, which indicates the presence of bio electrical charges everywhere. Can some help me understand what exactly is new here. I knew that something is new.
What you are talking about is the functional use of electrical impulses to active muscle. This article is talking about electrical potential as signalling mechanism for cell health, than can be used by a tissue to eject aging or sick cells
From a layman's perspective, another interesting (somewhat related?) example of a long-range effect that is not determined by neurons themselves (also a recent Quanta article: https://www.quantamagazine.org/once-thought-to-support-neuro...)
Even since reading about Michael Levin's work, I've been sold that there is a lot going on in terms of bioelectricity outside of neurons. But I haven't seen that much progress. This is one interesting, albeit simple example.
>In this way, bioelectrical flow across cell membranes lets tissues test which cells are the least healthy and mark them for extrusion. “They’re always pushing against each other and bullying each other. And what they’re doing is probing each other for which one’s the weakest link,” Rosenblatt said. “It’s a community effect.”
This fits with my model of how high levels of cooperation succeed in biology. Even in a community as homogeneous as cells you have the risk of defectors (cancer), or just poor members. As such you need a process to continually test your community members.
Why not simply say electricity?
You're rght. Light? thats just EMF. Infra Red? Emf. Xrays? It's all EMF man.
At least thats ITU regulated frequency bands. I wonder if the ITU regulates biogenic DC signalling frequencies?
The article notes that bioelectricity is just referring to electricity not occuring in the heart or brain which has a different specialized name. Simply saying electricity is captures more than the cell types reported on.
Because that is useless? The physical phenomenon is so very, very different in biological systems compared to the metal-wire electricity our electrical devices are based on that they are entirely different things.
For example, charge carriers are electrons in metal wires vs. ions in biological systems. That has huge implications, because moving around ions is a lot harder, and slower.
In a metal wire the electrical field is established from beginning to the end, and that means that the electrons at the end start moving at pretty much the same time as the ones at the other end, no matter how long the wire. That means in a metal wire signals move at a significant fraction of the speed of light in a vacuum, because it is the speed of the electrical field and not that of the charge carriers that matters.
In a biological system electrical fields are tiny! The way the signal propagates in an axon is much more cumbersome, expensive, and slow. Speed of signal propagation is ca. 1/2 to at most 100 m/s (for thick myelinated axons). The signal is propagated by jumping in very tiny steps along the axon's inner surface. (https://youtu.be/tOTYO5WrXFU)
This also makes The Matrix movies' main premise about humans as batteries a little strange: Sure, there's lots of electrical activity, but it is in trillions of very tiny places across nanometer distances. And it is created by moving ions around (at great energy cost).
So anyway, what actually physically happens in an electrical grid of metal wires, or in a biological system are vastly different things. It is not the same "electricity", the only thing they have in common is that electrical fields and charge carriers (but different ones) are involved. But the way it is structured, created, propagated is entirely different in both cases.
Yes, but how do they handle Byzantine fault tolerance?
T-cells. :P
Could this lead into how there are people who thing non ionising radiation sources affect them?
One acquaintance, after years of trying to work out what was wrong and believing EM missions may play a role turned out to have hemochromotosis (genetic disorder characterized by excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron) which is fixed by regular blood donations.
Here's a study from 2023 where they apply external electricity to improve healing rate of wounds:
https://pubs.rsc.org/en/content/articlelanding/2023/LC/D2LC0...
It enabled healing of diabetic wounds that are otherwise hard to heal.
Michael Levine really opened my mind to phase space in biology.
Electricity is the core of a single cell functionality as well, most biomolecules are on the exact boundary between a conductor and an insulator (and likely switch the state based on other molecules binding, pH, etc). A group of cells electricity is a higher level abstraction of that.
https://medium.com/the-physics-arxiv-blog/the-origin-of-life...
makes me wonder what effect a low current flowing through the body would have on this process. would it hinder/disrupt this coordination?
The article describes the mechanism in some detail near the end. As I understand it, it's not really "coordination" in the sense that they exchange messages through the electricity.
It's more that every cell has to maintain a voltage difference between the inside and outside ("membrane potential"). A healthy cell does that constantly using "ion pumps" that use chemical energy (ATP) to increase the potential.
If that potential falls below a certain threshold, certain molecular mechanisms (voltage-sensitive ion channels) inside the cell are triggered that lead to ejection.
Interestingly, are also other mechanisms (pressure-sensitive ion channels) that will "intentionally" make it harder for a cell to maintain its potential if it's already weakened or if the surrounding region is very crowded.
As such, I think the effect of current would depend on the way how it would change the voltage differences of the individual cells.
It'll blow their minds when they start researching chi kung and realise it's possible to draw in more energy by breathing and move it round the body. It's also possible to feel some kind of field around the body.
Auras and chakras don't sound so silly now do they.
"It'll blow those Chemists' minds when they start researching Alchemy and they realize the incredible power of mercury and lead to rejuvenate the body and lead to an elixir of youth!"
"It'll blow those Astronomers' minds when they start researching Astrology and the powerful effect of being born under auspicious constellations!"
__________
If the ancient guru knowledge is so great, what testable predictions does it offer, where "auras" are a causal mechanism?
In other words, not: "Thou must intake the golden aura of oats and fiber by eating some, to counter the dark brown blockage of your Pu-point." The folk remedy might well solve your constipation, but it wouldn't be evidence for the mythology around it.
Lol no, this crank shit sounds dumb as fuck haha. Kamehameha!
> possible to draw in more energy by breathing and move it round the body
We already know what haemoglobin is thanks
For those interested in more details and quite mind blowing examples, here is a fascinating interview with Michael Levin (one of the researchers mentioned in the article).
https://youtu.be/c8iFtaltX-s?t=4751
Start at 1:19:11, the stuff before is him talking about biology, but from an intelligence perspective. After this time stamp is his retrospective on his bioelectricity research over the years, showing also examples of how they got a frog embryo to produce eyes, and many more things.
Thanks for sharing this timestamp - Levin's retrospective on bioelectricity research is compelling. What fascinates me most is how his work challenges the gene-centric view of development. The experiments showing bioelectric patterns can override genetic instructions (like inducing eye formation in non-eye tissue) reveal a whole layer of morphogenetic information we're just beginning to understand.
It was known for a long time that some reflexes and responses are mostly spontaneous and don't require decisions from the mind. Such reactions, such as pulling away when touched a hot surface, do require muscle contraction which in turn requires electrical pulses, which indicates the presence of bio electrical charges everywhere. Can some help me understand what exactly is new here. I knew that something is new.
What you are talking about is the functional use of electrical impulses to active muscle. This article is talking about electrical potential as signalling mechanism for cell health, than can be used by a tissue to eject aging or sick cells
From a layman's perspective, another interesting (somewhat related?) example of a long-range effect that is not determined by neurons themselves (also a recent Quanta article: https://www.quantamagazine.org/once-thought-to-support-neuro...)