The Homunculus Among Us
Happy Halloween, everyone!
This month I’m excited to talk about a subject that I wanted to include in August’s letter about Carapace and Chrysalis and neurologically controlled mecha. But, that post was very long and I knew I had a solid newsletter’s worth of information on this subject, so I decided to hold off. But the time has come! Please let me tell you about body maps.
A “body map” is just your brain’s map of your body. It includes things like your size and shape, but also the position of your body in space; each part relative to the rest of you, and relative to other objects around you.
My favorite thing about the human body map is that it is surprisingly malleable! When you studying neuropsychology you learn about the sensory homunculous in the postcentral gyus, and the motor homunculous in the precentral gyus (more info here), and how each of these has a nominally pre-set organization to where each body part is represented. This is the bit that goes with your right heel, this is the bit that goes with your tongue, and so on, with more area devoted to body parts with more sensory nerves/fine motor control. And that seems fairly straightforward, and you think you’re ready to move on.
But no! We are a tool using species! And as such, we have the capacity to change up our body map to include tools we’re using. In fact, we share this trait with many of our primate cousins, although only apes are generally found using tools in the wild, or even in captivity.
Unless, of course, some human scientist has taught the monkey to use tools in order to study them, as Dr Iriki has done in a series of experiments that first proved some further branches of the primate family can learn tool use, and later to study the use of tools in neurological body maps.
Engaging Monkeys for this is helpful because you can be fairly sure that the monkey (macaques in this case) will not have a prior experience with the tool use you’re teaching them, allowing for a proper before and after to compare.
Dr Iriki’s experiments demonstrated that, on a neurological level, the brain can and does update the supposedly pre-set map by expanding the area of tool using body parts to include the area the tool can affect, even in not-naturally-tool-inclined primate species.
So the body map isn’t just about where your body is, it’s where it might be, and maps how far you may be able to impact your environment with the tool in your hand. It’s how the swordmaster becomes one with the blade, and how you don’t need to consciously calculate how you have to move your pen to hit the paper.
So that stunning elasticity makes times when the brain fails at updating the homuncili even more interesting. And it happens all the time! We’ve all seen an adolescent or toddler who’s just had a major growth spurt tripping over themself as they mis-estimate the size and location of their feet, legs or overall height.
One of the most well known neurological misfires in this realm is Phantom Limb Syndrome, in which someone who’s undergone an amputation experiences distinct pain in a limb that simply isn’t there anymore- often with a clenching sensation that they can’t release.
I’m not sure how many people know that one of the preferred treatment methods, developed by the well know neurologist Dr Ramachandran, is an astonishingly low tech box of mirrors that seems like it’s out of a magician’s stage show. The impacted person will put their remaining arm (or leg, if the amputation was a leg) into a box containing a mirror. They mentally tell both their arms- the one that is there and the one that isn’t, to perform the same motions, while looking at the mirror. The mirror gives the illusion of two intact limbs, moving as the brain would expects them to, if there were two limbs. The brain accepts that the limb is safe, and not clenched, and the pain recedes.
The patient is completely aware of what they are doing. There is no trick or insight gap involved- they know their limb is still gone. They are consciously playing a trick on their own body map. It’s an astonishing reverse placebo effect- you know this isn’t fixing the injury but it works anyways!
Brains are so incredibly weird.
So, if phantom limb syndrome happens when parts of the brain fail to update the body map to keep up with conscious awareness, and we also know that body maps can morph to include tools, then we can understand why many of us duck as we drive our car through a low tunnel; our body map has adapted to view our familiar vehicle (a tool we know well) as an extension of the body, even though we know we are not cars. And we, in our car-bodies, do not want to bump our heads.
Tragically, as far as I can remember, I’ve only seen this represented in speculative fiction twice. Once, when Captain America gets his new super-sized body and promptly runs through a store window display because he can’t yet estimate his strides or turning radius. Sadly, he then masters his new proportions by the end of that chase scene, because I am not in charge of the MCU. The other example is when Twilight Sparkle from My Little Pony is turned into a human, having not seen a human before, and has no idea how to manage bipedal motion and is completely baffled and disgusted by human hands. This was also wrapped up promptly but I am pleased they hung on to it at least a bit longer.
I am sure others have done this- please do feel free to share examples with me. I never get tired of it.
I want werewolves crashing into things. I want mech pilots trying to reach for something as if they were still 40 feet tall with arms to match. I want body-swap episodes with characters completely thrown off by the bodily signals they’re getting from this unfamiliar nervous system.
I want to explore just how inhuman we can make a cyborg body before the brain can’t cope anymore. Not because I have any interest in exploring body modification as dehuminization as I’ve discussed before, but because I think cyborgs in scifi rarely get as weird as some people would try for, and that’s just leaving money on the table.
We’ve had some experimental data since literately 1980 that when humans are given the chance to control a virtual reality avatar with, say, 6 segmented, lobster-like legs, via moving their real limbs, they can learn to control them even when the movement translations are too complex, counterintuitive, and nuanced for them to be able to articulate consciously. The homunculi in your brain can stretch to that. Humans can even feel sensation in nonexistant VR limbs, given the right circumstances. Which seems to me to mean that your brain could learn to move a 6 legged lobster-centaur cyborg body if you wanted to and one was available.
I personally have questions about whether that would lead to an increased rate of people getting “the yipps” from daily life, the way top athletes like Simone Biles or top musicians do when they potentially over-saturate nuanced motor neuron connections, but that will have to wait for another newsletter.
In the mean time, if you want to read more about this, I will suggest two books; The Body Has a Mind of It’s Own, by Sandra and Matthew Blakeslee, and The Future of the Mind, by Michio Kaku. They’re both fascinating and very accessible books.
Before I close out, I will risk irritating my readers, and hope you’ll forgive me. I know people the world over are sick to death of hearing about the US election. God knows I am. But I am personally asking you, if you are legally able to do so, to please go out and vote this election- up and down the ballot. Whatever you hold dear, Trump is worse for it, whether that’s Palestine, the climate, or issues closer to home.
Whatever you value, we need a functional planet for it, and we frankly do not have time to mess around with another Trump presidency when it comes to climate action. Particularly when he’s out here telling people directly that if they vote for him, they will never have to vote again.
So I ask you, from the bottom of my heart and for my daughter’s future, to protect our planet and vote Harris, and contribute to Democrat election funds if you can. Remember - a 3rd party vote takes away from Harris, not Trump, and so may as well be a vote for Trump. And not voting doesn’t work like boycotting. The government gets it’s money from your taxes, not your votes. To refuse to vote is not to drive the left further left, it’s to make yourself irrelevant to the processors that govern all our lives, while your tax dollars fund whatever the people in charge are funding.
And, on a far more petty note, the last Trump presidency was hell on my mind and body and I honestly do not know that I would have it in me to keep up these newsletters through another one, as much as I love writing them and hearing from you all.
In sympathy for everyone putting up with this, and in thaks for everyone donating, door knocking and voting, I’ve made both my ebooks free on Gumroad and Itch.io until we have election results. I’ve been told they’re good books for this moment.
Allright, I’m off my soap box now, and on to finishing up the beat-by-beat outline of book 3’s act 1, which I hope to draft in November. Wish me luck!
Best wishes,
Lee Brontide
Thank you for reading Shed Letters! As a subscriber to the newsletter, you have exclusive access to bonus novella Doll’s Eye View. Please check it out, and consider reading my published novels, Secondhand Origin Stories and Names in Their Blood. You can find a variety of ways to read or listen to those here.