Satori Neuro: Your book, We Are Electric, has a special place in our hearts at Satori Neuro because we hear the seeds of it were planted when you met Amy more than a decade ago. Can you tell us how that happened?
Sally Adee: I was an intern at IEEE Spectrum, a magazine aimed at electrical engineers, and I was on the semi-conductor beat because nobody wanted it, basically. One of the things that was brilliant about that beat was that I was able to do a lot of stories around the chips they were designing to do neuro-integration. I met Amy when she was a DARPA program manager, and she told me about a project she was running that was about accelerated learning. I couldn’t believe it. I’d been used to thinking about neural interfaces as a matter of prosthetics and regaining function, or output. I had done a lot of stories about people who make these robot arms that open and close with your neural signal, but then I was like, so wait, if you put electricity into the brain, it can improve the brain’s function?
When I got to New Scientist, it was much more the type of publication where you could try a gonzo stunt like experimenting on yourself in the service of science journalism. DARPA had some credible results by then and I was able to go and try it out for myself.
SN: So that’s how bioelectricity started for you – let’s talk a bit about how it started as a field. Your book mentions different types of electricity and the battle between physics and biology for ownership of the topic. How did physics come to dominate?
SA: People from antiquity had been curious about electricity in its manifestations, like if you rub a piece of amber it will attract a bunch of little fluff. There were some metallic types of stones that could attract actual known metals, and the ancient Greeks used to hold electric fish on their feet when they had gout or something to relieve the symptoms. Of course everybody knows about lightning. But you can imagine how mysterious and completely unconnected these separate things would have felt or seemed to people before there was some kind of scientific framework to see them through.
Then in the 1600s with the invention of electrostatic generators, people started to be able to play with this stuff and develop theories about how this is all connected. Lightning and the stuff that’s coming out of an electrostatic generator: are those the same thing? Are electric fish actually electric?
That’s when Luigi Galvani starts looking into this idea that maybe what animates our nervous system was not a hydraulic network, as previously thought. Galvani had also seen people using electrostatic generators to zap various animals and people, and monks were electrifying crowds of people through wires, and he was like wait a second, what if it’s the same thing? He starts doing years and years of experiments on frogs to try to understand what it is, whether that is a kind of nervous electricity, and whether nervous electricity can join the pantheon of lightning and the stuff that comes out of an electrostatic generator as all being part of the same thing.
SN: And he pulls it off?
SA: Well, sort of. Galvani publishes this paper that is met with rapturous response initially, and then came Alessandro Volta, who was a very ambitious physicist. He wanted to be an “electrician”, which at the time had a much more glamorous connotation than we give it today. It’s sort of on par, or shares a vibe with ‘rocket scientist’. He had ambitions to be the best of the electricians, and he just did not believe Galvani’s contention. He was like, ‘This is an anatomist, what does he know about electricity.’
They spent five or six years going back and forth with these respectful but quite intense disagreements. When I was reading accounts of it, it reminded me of X. The guys themselves were pretty respectful with their disagreements but the people around them would write letters in support of their guy, sort of like, “He has written with the thunder of truth!” and then the other guy’s paper came out they would switch sides and be like “well, obviously! I’ve also replicated this!”. There was just this very bombastic war where everybody had to choose sides.
In the end, Galvani did demonstrate beyond the shadow of a doubt that the stuff that is in cells was able to transmit a signal that was at the very least chemio-electrical. But from the argument, Volta had actually derived the idea of the voltaic pile which would become the battery. He basically blew everybody out of the water with this invention that was so useful for science. Unfortunately, nobody was able to figure out a use for Galvani’s correct contention that it was an electrical signal that was traveling through the nervous system. Having a functioning device won the day.
SN: Cut to the present moment: incredible developments are happening every day in this field. History is sort of repeating itself, in that genetics has seized the public imagination, and the electric components of what shapes us developmentally have been totally neglected.
SA: Yeah, so your body plan isn’t determined by your genome. It might code for what color your eyes should be, but it doesn’t determine, for example, how many of those eyes you should have. From a cell’s perspective, when you’ve just been conceived, it needs to proliferate into 40 trillion cells, or whatever it is, in order to make an adult human being. The shape of that adult is incredibly consistent across species, but how does that first cell know? Its first task is actually to tell its left from its right. Because you have to be able to tell your left from your right in order to put two arms on either side and not one in the middle and one on your head, and whatnot.
Michael Levin and others have shown it achieves this through self-electrophoresis. The cell somehow pushes all of its ion channels onto one side of itself, which is what creates the current that drives the first ability to orient itself. Throughout development, electrical currents and voltages are key in shaping us into what we are. And I find that such a wild idea.
SN: So that electrical influence is hugely important throughout our lives. When you gave the example of lightning, I was reminded of the now-out-of-fashion view of how life came to be, with the sort of lightning strike into the primordial goo and the idea of the ‘spark of life’. In researching and writing the book, did you gain any further insight into what ‘being alive’ means?
SA: Yes!! Our ion channels are descendants of the same ion channels that were in some of the first goo—when everything was unicellular life forms. People think of bioelectricity as something that passes our action potentials on, but the nervous system did not invent that; it piggybacked on a much more ancient system. It’s a whole different system of biological communication, and it’s like a command and control center that used to be used just to distinguish self from not-self. Then it got conscripted into how we move and act in the world, and maybe consciousness after that. But the fundamental bit of that is that all of our channels that allow ions to get in and out of our cells, those are some of the oldest things about us.
Before you had a cellular membrane, you could have pieces, but you couldn’t have forces. These forces are crucial in the difference between things that are alive and things that aren’t alive. I don’t think a lightning bolt (except a metaphorical one) was necessary. Once you had a membrane encapsulating a cell, you had an electrical potential. Because if there are ions in the water—which there always have been—you’re going to have an imbalance which is going to give you a membrane potential. Then you get little proteins tunneling through.
So once you have a membrane, and thus an electrical difference, and once there’s an ion channel, and once the cell can figure out how to control those electrical differences—suddenly you have something that is alive.
SN: We’re getting into an area that I believe your next book might explore. Can you tell us anything about your current research?
SA: In this one, I’m going deeper into the ‘why’. Why does life use electricity, not just for signaling, but for absolutely everything? Why do we all use electrical voltages in order to maintain certain types of homeostasis? It comes down to the fact that we evolved on the Earth, which is a giant capacitor. The atmosphere and the ground form a natural capacitor, with the ground holding a negative charge, and the ionosphere holding a positive charge (see: lightning).
There’s this really intricate relationship between the electrical nature of the planet that we live on and all of these things we do that are electrically grounded. When you look at the human body through the lens of ATP and the electron transfer chain, you could kind of squint and understand breathing out is just a way to shed our extra electrons. I’m working very hard right now not to sound like a crazy person with lots of red string and a cork board, but I think it’s coming together.