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Yes, I believe that the linked article oversimplifies when talking about a "bioelectric" state, perhaps because this sounds more appealing to those familiar wit

Yes, I believe that the linked article oversimplifies when talking about a "bioelectric" state, perhaps because this sounds more appealing to those familiar with electrical and electronic technologies. The actual state that is described is determined by the chemical concentrations of various kinds of ions and molecules along and across the body of an animal. The distribution of electric potential that appears as a consequence of the chemical concentration variations, due to the fact that the atomic ions and also many of the molecules involved are electrically charged, is just a coupling mechanism between those chemical concentrations, so that when one of them is changed that tends to also change the concentrations of other atomic or molecular ions. The same "bioelectric" state (i.e. electric potential distribution) could appear as a consequence of distinct distributions of the ions and most certainly those seemingly identical "bioelectric" states would behave quite differently. This is similar with what happens in semiconductors, whose behavior cannot be simulated based on just the distribution of electric charge, but one must account separately the concentrations of all kinds of charge carriers, e.g. electrons, holes, fixed crystal defects etc.

LarsDu88 2y ago
I think I want to clamp down on the hyperbole a bit here, and I think its obvious the author is targeting the software engineer folks who might not be familiar with developmental biology or evolution. The planaria has evolved a mechanism by which its body plan can be recapitulated from the distribution of electric potential. When it gets cut in half, the electric potential changes, but this is still enough information for the vivisected halves to redifferentiate. The trade off is, of course, there is only so much information in an electric potential with regard to the patterning of a complex organism, so its hard to imagine a cheetah or a pig pulling off this same kind of trick. The idea of some subdivision of an animal having its own prerogatives is not some sort of new idea. It goes all the way back to Richard Dawkin's 1970s book "The Selfish Gene" which lays out exactly where the "incentives" are for cells, genes/cistrons, cancer, transposons, etc... Just because there's some example now of something vaguely reminiscent of semiconductors (which is cool for sure!) does not mean we're gonna start rethinking everything in biology.
- adrian_b 2y ago
  > When it gets cut in half, the electric potential changes, but this is still enough information None of the linked articles contains any evidence about some direct influence of the electric potential, but only about the influence on differentiation of the variable concentration of ions. They did not manipulate the planaria with electrodes, but with a drug that has manipulated the concentration of ions, by blocking some of the paths through which some ions are transported through membranes. All the talk about "bioelectricity" appears superfluous. The variable electric potential is just a side effect of the variable ion concentrations, which complicates their behavior by introducing a coupling between the movements of different kinds of ions.
  - bboygravity 2y ago
    That kind of sounds like saying that talking about "electricity" is superfluous when describing how chemical batteries work, because it's all about ions. Yeah, sure... but both are totally relevant?
    - adrian_b 2y ago
      Given a state described by the distributions in space of the various kinds of ions, you can compute the distribution in space of the electric potential. Therefore including the electric potential in the state is superfluous. Given the distribution in space of the electric potential, you cannot compute the entire state, which includes the distributions in space of many kinds of ions, simply because there are many kinds of ions. Only when there had been a single kind of ions, it would have been possible to describe the state using the electric potential. All the ions move continuously through very complex circuits comprising a network of pores through the cellular membranes. Through some of the pores the movement is "passive" i.e. for each kind of ion that may pass through a given kind of pore the ionic current is determined by both the local gradient of the concentration of that kind of ion and the local gradient of the electric potential. This is the only place where the electric potential matters. Through other kinds of pores, the ion transport is "active", i.e. the so-called ionic pumps move certain kinds of ions regardless of the gradients of the ionic concentrations and of the electric potential (within certain limits, too large gradients can block an ionic pump). If you want to simulate the ionic current network of an entire organism, you must compute the electric potential inside the simulation. When you observe a living organism, measuring the electric potential is much easier than measuring directly any kind of ion concentration and in many cases one can estimate the ionic concentrations of interest from the measured electric potential and from additional information. While accounting for the electric interactions inside an organism is essential, talking about a "bioelectric" state of an organism that would determine its development is just meaningless pseudo-scientific mumbo-jumbo. "Bioelectricity" is an appropriate term when discussing the electric sense organs or the electric weapons of various animals, where the side-effect of the generation of electric potential differences by differences in ion concentrations is exploited in such a way that the effect is cumulative over large ensembles of cells.
fngjdflmdflg 2y ago
This makes a lot more sense. I had a hard time visualizing the existence of a biological voltmeter measuring electric potentials and using that to somehow change development of the organism. Seems like another case of "correlation does not equal causation" based on your comment.

LarsDu88 2y ago

I think I want to clamp down on the hyperbole a bit here, and I think its obvious the author is targeting the software engineer folks who might not be familiar with developmental biology or evolution. The planaria has evolved a mechanism by which its body plan can be recapitulated from the distribution of electric potential. When it gets cut in half, the electric potential changes, but this is still enough information for the vivisected halves to redifferentiate. The trade off is, of course, there is only so much information in an electric potential with regard to the patterning of a complex organism, so its hard to imagine a cheetah or a pig pulling off this same kind of trick. The idea of some subdivision of an animal having its own prerogatives is not some sort of new idea. It goes all the way back to Richard Dawkin's 1970s book "The Selfish Gene" which lays out exactly where the "incentives" are for cells, genes/cistrons, cancer, transposons, etc... Just because there's some example now of something vaguely reminiscent of semiconductors (which is cool for sure!) does not mean we're gonna start rethinking everything in biology.

adrian_b 2y ago
> When it gets cut in half, the electric potential changes, but this is still enough information None of the linked articles contains any evidence about some direct influence of the electric potential, but only about the influence on differentiation of the variable concentration of ions. They did not manipulate the planaria with electrodes, but with a drug that has manipulated the concentration of ions, by blocking some of the paths through which some ions are transported through membranes. All the talk about "bioelectricity" appears superfluous. The variable electric potential is just a side effect of the variable ion concentrations, which complicates their behavior by introducing a coupling between the movements of different kinds of ions.
- bboygravity 2y ago
  That kind of sounds like saying that talking about "electricity" is superfluous when describing how chemical batteries work, because it's all about ions. Yeah, sure... but both are totally relevant?
  - adrian_b 2y ago
    Given a state described by the distributions in space of the various kinds of ions, you can compute the distribution in space of the electric potential. Therefore including the electric potential in the state is superfluous. Given the distribution in space of the electric potential, you cannot compute the entire state, which includes the distributions in space of many kinds of ions, simply because there are many kinds of ions. Only when there had been a single kind of ions, it would have been possible to describe the state using the electric potential. All the ions move continuously through very complex circuits comprising a network of pores through the cellular membranes. Through some of the pores the movement is "passive" i.e. for each kind of ion that may pass through a given kind of pore the ionic current is determined by both the local gradient of the concentration of that kind of ion and the local gradient of the electric potential. This is the only place where the electric potential matters. Through other kinds of pores, the ion transport is "active", i.e. the so-called ionic pumps move certain kinds of ions regardless of the gradients of the ionic concentrations and of the electric potential (within certain limits, too large gradients can block an ionic pump). If you want to simulate the ionic current network of an entire organism, you must compute the electric potential inside the simulation. When you observe a living organism, measuring the electric potential is much easier than measuring directly any kind of ion concentration and in many cases one can estimate the ionic concentrations of interest from the measured electric potential and from additional information. While accounting for the electric interactions inside an organism is essential, talking about a "bioelectric" state of an organism that would determine its development is just meaningless pseudo-scientific mumbo-jumbo. "Bioelectricity" is an appropriate term when discussing the electric sense organs or the electric weapons of various animals, where the side-effect of the generation of electric potential differences by differences in ion concentrations is exploited in such a way that the effect is cumulative over large ensembles of cells.

fngjdflmdflg 2y ago

This makes a lot more sense. I had a hard time visualizing the existence of a biological voltmeter measuring electric potentials and using that to somehow change development of the organism. Seems like another case of "correlation does not equal causation" based on your comment.