New paper!
Cytoelectric Coupling: Electric fields sculpt neural activity and “tune” the brain’s infrastructure.
Brain waves carry info and alter the brain on the molecular level. This tunes the cytoskeleton, optimizing network function.
Work by Dimitris Pinotsis.
https://doi.org/10.1016/j.pneurobio.2023.102465
I usually hold off skepticism until after I read something. But you do you.
How do you know it is hard to believe until you hear the arguments? Until then, it's just "new".
It's not like we are proposing a new law of physics or new biological principles.
For example, electrical fields guide embryonic development, organizing structures throughout the body. That's how a cell "knows" which part of the finger to migrate to
I would be skeptical if that mechanism shut off after development and wasn't used by the brain, which is electrical.
Yes. Because I am now aware of the evidence and arguments. See how that works?
All that really matters is where you land, Kari.
Always fun to chat with you.
For example:
Brainless Embryos Suggest Bioelectricity Guides Growth
https://www.quantamagazine.org/brainless-embryos-suggest-bioelectricity-guides-growth-20180313/
Haha! I *love* that!
BTW, if you need convincing about the influence of electric fields in the brain, check these out.
Cell bodies pressed together. There are no synapses there. Just large expanses of unmyelinated surface area. That is ideal for a direct electrical influence between neurons, i.e., ephaptic coupling.
@dbarack @NicoleCRust @ekmiller
Hi David -- interesting! I always read your paper with Krakauer as saying that the our explananda for cognition are our internal representations and the transformations we perform over them (a mental level description), with substrate-independent electrical activity as the most fruitful explanans on a neural level (rather than circuits).
But here I think you're saying that the explanatory target is electrical activity itself, which normally sits at the neural level. Could you clarify? Or just tell me to wait for your book chapter ;-)
@sandervanbree @NicoleCRust @ekmiller Great question. I'm a reductionist--in fact, I'm worse: I'm an identity theorist. I think that mental representations will be type identical to physical types. What types? Those are the physical-substrate-independent electrical activities. So the mental level description = a physical level description (despite being substrate-independent! You have to target the right physical level, and you still get substrate independence). And, the explanatory target (the explanandum) is the cognitive phenomena, not the electrical activity (which is the explanans, what does the explaining), but I take it that that is what you meant.
Now, explanation might be intensional. I can explain that the cat is on the mat without explaining that Granny's favorite critter is on the mat (to provide a Fodor-inspired example). Note though that this is intensionality for the explanandum. There is also intensionality for the explanans. I can explain that the cat is on the mat (the explanandum) because the door was left open, or because Cousin went out to play. These are also distinct. In the first case, the explananda are not the same, and explanans cited to explain the one may not explain the other. In the second case, the explanans are not the same, and they might explain different explananda. (1/2)
@sandervanbree @NicoleCRust @ekmiller
So, to be annoyingly philosophical, it depends on what you mean by "our explananda for cognition are our internal representations". The explananda for cognition is intelligent behavior (or near enough). The explanans are physical things--those are the internal representations (namely, spaces of electrical activity). Applying the foregoing, the electrical activity and the mental representations are type identical explanans that explain the explanandum of intelligent behavior, but they might explain different explananda as well.
I think this is actually important. A lot of explanans (such as neural electrical activity) are type identical to other explanans (such as mental representations) but simply aren't suited to some explanations that their identical counterparts are suited to. Referring to biological neural electrical activity qua biological activity won't help explain the cognitive phenomena evident in artificial neural networks, for example, even if referring to that biological neural activity qua mental representations might just do.
Also, because of the intensionality of explanation, you can give an explanation of spaces of electrical activity without giving an explanation of mental representations (or vice versa). But note, the explanans for cognition are our internal representations, whether neural or mental; when the explananda are those representations, the explanatory target has changed. (2/2)
@dbarack @NicoleCRust @ekmiller
Thank you for taking the time to write out this wealth of information. I think I get what you're saying: intelligent behavior is the explanandum, and substrate-independent e-fields are the explanans, and so too are internal representations because they are actually type-identical to those fields. But their distinction is nevertheless important because in other explanatory contexts it might not be the case that the e-fields and internal representations can be exchanged for each other, which we see for instance if we move to the explanatory context of ANN behavior. Clickidy?
Another question that interests me -- and I know it interests you too -- is whether manifolds are real objects. It was either a talk or a tweet where you made a passing comment that you think they are, and it seems not too far off from the point you're making today. I always think of manifolds as good old descriptions only -- which of course may well figure in scientific explanations. Will questions of realism be covered in your book also? I hope it will.
Yes! Get it out there!
@NicoleCRust @dbarack @ekmiller
Here are two more (older) data points on the causal effects of weak electric fields ...
on spikes:
https://www.jneurosci.org/content/30/45/15067
and network activity:
https://www.jneurosci.org/content/27/11/3030
Clinical effects of transcranial electrical stimulation with weak currents are remarkable considering the low amplitude of the electric fields acting on the brain. Elucidating the processes by which small currents affect ongoing brain activity is of paramount importance for the rational design of noninvasive electrotherapeutic strategies and to determine the relevance of endogenous fields. We propose that in active neuronal networks, weak electrical fields induce small but coherent changes in the firing rate and timing of neuronal populations that can be magnified by dynamic network activity. Specifically, we show that carbachol-induced gamma oscillations (25–35 Hz) in rat hippocampal slices have an inherent rate-limiting dynamic and timing precision that govern susceptibility to low-frequency weak electric fields (<50 Hz; <10 V/m). This leads to a range of nonlinear responses, including the following: (1) asymmetric power modulation by DC fields resulting from balanced excitation and inhibition; (2) symmetric power modulation by lower frequency AC fields with a net-zero change in firing rate; and (3) half-harmonic oscillations for higher frequency AC fields resulting from increased spike timing precision. These underlying mechanisms were elucidated by slice experiments and a parsimonious computational network model of single-compartment spiking neurons responding to electric field stimulation with small incremental polarization. Intracellular recordings confirmed model predictions on neuronal timing and rate changes, as well as spike phase-entrainment resonance at 0.2 V/m. Finally, our data and mechanistic framework provide a functional role for endogenous electric fields, specifically illustrating that modulation of gamma oscillations during theta-modulated gamma activity can result from field effects alone.
@lcparra @NicoleCRust @dbarack @ekmiller In 2005 or 2006 I saw a talk given at Stanford by a physicist named Jose Acacio de Barros, who, as I recall, discussed the possibility that synchronized firing in a given cortical column could influence activity in other, more distal neurons. 20 years have intervened and my memory for the details of the talk is not as strong as for the impression it made on me, a pre-PhD RA, about the incredible range of possibility in neuroscience. Anyway, after seeing these threads, I decided to email him this morning. He just responded with some relevant citations:
Suppes, P., de Barros, J. A., & Oas, G. (2012). Phase-oscillator computations as neural models of stimulus-response conditioning and response selection. Journal of Mathematical Psychology, 56(2), 95-117. https://doi.org/10.1016/j.jmp.2012.01.001
E. Vassilieva, G. Pinto, J. de Barros, and P. Suppes, "Learning Pattern Recognition Through Quasi-Synchronization of Phase Oscillators," in IEEE Transactions on Neural Networks, vol. 22, no. 1, pp. 84-95, Jan. 2011, doi: 10.1109/TNN.2010.2086476
Hope these are of interest!
@dbarack +1000
Check these out.
Cell bodies pressed together. There are no synapses there. Just large expanses of unmyelinated surface area. That is ideal for a direct electrical influence between neurons, i.e., ephaptic coupling.
@ekmiller Worth reading even if just for this: "Ephaptic coupling to LFPs can organize neural activity". Looking forward.
@ekmiller I got to "Thus, it stands to reason that electric activity and fields could play a direct role by configuring and stabilizing cytoskeleton proteins." but I confess that there was nothing in the preceding paragraphs that let me make that leap with you.
Help me out please? What's the experiment that would disprove the the Cytoelectric Coupling Hypothesis? Maybe propose two: one free of all tech considerations, and one that might be achievable now? Thanks!
@schoppik There's always the null hypothesis. No effect on proteins. If there are effects, are they good or bad?
I am not a molecular biologist. I can't tell you the deets. But others can and hopefully will.
EFs are ideal for tuning up any bio system. Tuning a system means getting the parts to harmonize. EFs spread and share influences at the speed of light.
@ekmiller I imagine any paper about the electric fields for cognition that also mentions both Hameroff/Penrose's microtubule model and tensegrity could invite some skepticism. Those topics are associated with a lot of really noisy, nonrigorous/inaccurate, and sometimes bizzare writings. Skepticism, though, comes from a word that means "to consider," and this paper has a lot of interesting things to consider.
Excited to dig into some of the references too, especially about electrodiffusion. I've been wondering about how electricity moves in the brain other than through action potentials, since phospholipids are conductive https://www.pnas.org/doi/pdf/10.1073/pnas.67.3.1268 not insulated like electrical cables. So are the cytosol and interstitial fluid.
The electricity is going all over the place. The force of the AP is greater and more action packed, but the diffusing electricity has to be affecting things too
@axoaxonic Action potentials are large but the brain is not single neurons. Smaller effects like EF fluctuations multiplied over millions of neurons add up to huge effects.
Also keep in mind that neurons do not spike continuously. In fact, most of the time, they are not spiking. By contrast, fluctuations in EF are happening continuously.
BTW, I think it is a strange attitude to be skeptical about a paper because it cites one paper that you don't like.
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