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Hello, here’s a rambling thread-under-construction about my understanding of Functional Neurological Disorder 
what is it? what isn’t it?
what is it? what isn’t it?
Normally I plan these things out but not today. So we’ll do a bit at a time and I’ll try to notate the breaks. Ok. Let’s get started!
Functional Neurological Disorder is a kind of health problem that involves both subjective disturbances (like pain, blindness, numbness, tingling)
and objective dysfunction (weakness, paralysis, seizures, etc)
it is also the subject of ~400 years of medical debate
and objective dysfunction (weakness, paralysis, seizures, etc)
it is also the subject of ~400 years of medical debate
Functional Neurological Disorder (FND) originally went by the name Hysteria, and then Conversion Disorder. It was renamed FND in 2013, a move most people who have it welcome.
But how best to understand FND and resolve the many debates around it?
But how best to understand FND and resolve the many debates around it?
Having marinated on this for a bit, I think @AlanCarson15’s* description of FND as “the price of how our brain works” best captures what’s going on.
(*who always seems to have the mot juste)
(*who always seems to have the mot juste)
That’s also an argument (IMO) for FND as a central concern of brain science, not a “fringe” disorder.
We’ll get into what “the price of how our brain works” means further down
but first: what ISN’T FND?
We’ll get into what “the price of how our brain works” means further down
but first: what ISN’T FND?
Given that society has been debating hysteria/CD/FND since the 1600s, we’ve had plenty of chances to get it wrong.
And oh, we really really have.
And oh, we really really have.
Let’s start with one of the most common and harmful: the idea that “hysteria” in the 1800s was really just women’s sexual frustration, which clueless male doctors treated w vibrators.
This narrative comes from a single scholar, whose claims went largely in examined for a long time. Then someone finally got around to checking and discovered it wasn’t just a historical error.
It was essentially a lie; academic fraud. https://www.theatlantic.com/health/archive/2018/09/victorian-vibrators-orgasms-doctors/569446/
It was essentially a lie; academic fraud. https://www.theatlantic.com/health/archive/2018/09/victorian-vibrators-orgasms-doctors/569446/
What else isn’t FND?
Well, despite the symptoms appearing neurological, it’s not due to large-scale brain damage. When scientists in the 1800s dissected the brains of deceased “hysterics,” they looked fine. Those findings held into the 1990s. Weird...
Well, despite the symptoms appearing neurological, it’s not due to large-scale brain damage. When scientists in the 1800s dissected the brains of deceased “hysterics,” they looked fine. Those findings held into the 1990s. Weird...
FND is also not primarily due to a pathogen, like viruses or bacteria.
Since getting FND, I’ve experienced how much of our common thinking about medicine is germ-oriented, and how that shapes our thinking.
With FND, it can really put you on the wrong track.
Since getting FND, I’ve experienced how much of our common thinking about medicine is germ-oriented, and how that shapes our thinking.
With FND, it can really put you on the wrong track.
Obviously with something like the coronavirus we see the damage that pathogens can wreak on the human body. But that’s not the only way things can go wrong.
There are other possibilities, especially for the unique systems that make up the brain.
There are other possibilities, especially for the unique systems that make up the brain.
One final (but incorrect) theory of FND is that it’s nothing: that FND doesn’t really exist.
This was famously expounded by Eliot Slater, mid 20th century.
In this view, FND is just a collection of other disorders that docs have failed to diagnose. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2166300/
This was famously expounded by Eliot Slater, mid 20th century.
In this view, FND is just a collection of other disorders that docs have failed to diagnose. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2166300/
Time and neuroimaging have not been kind to Slater’s view.
There are studies now that show FND arises from the brain, and capturing some of its unique dynamics https://link.springer.com/article/10.1007/s11910-019-0926-y
There are studies now that show FND arises from the brain, and capturing some of its unique dynamics https://link.springer.com/article/10.1007/s11910-019-0926-y
The symptoms of FND itself are also unique. They can be “internally inconsistent”, as in someone who has weakness that comes and goes.
They can get better or worse with attention.
They can sometimes closely resemble other disorders, but with something slightly “wrong”
They can get better or worse with attention.
They can sometimes closely resemble other disorders, but with something slightly “wrong”
They can also contradict the biology of the human body (numbness that contradicts nerve distributions) or even the laws of physics (functional blindness that doesn’t adhere to principles of optics.)
WTF?
WTF?
This is why one physician called hysteria “the mockingbird of nosology”, and Freud, who I am not particularly fond of, said hysteria “acts as though anatomy doesn’t exist.”
So many doctors concluded that hysteria is either imagined or faked.
It is neither of these things.
So many doctors concluded that hysteria is either imagined or faked.
It is neither of these things.
A much better explanation, given what we have today*, is “the price of how our brain works.”
*(firsthand accounts of patients, neuroimaging, improved statistical methods, advances in psych theory, computational neuroscience, embodied cognition, study of allostasis + affect)
*(firsthand accounts of patients, neuroimaging, improved statistical methods, advances in psych theory, computational neuroscience, embodied cognition, study of allostasis + affect)
So the next step is to talk about a high-level view of what the brain is doing, and how FND maps onto that.
We’ll get to that next time.
Break for today!
We’ll get to that next time.
Break for today!
Shout out to all the people who have suffered with this condition while being typically disbelieved, talked over, or otherwise erased from the narrative.
The fact that we have the space to speak and a community to hear us now is maybe the most important change in FND history.
The fact that we have the space to speak and a community to hear us now is maybe the most important change in FND history.
OK, time for Part 2, on How the Brain Works:
Standard disclaimer: the brain is ridiculously complicated and we still don’t understand many things about it. I especially don’t.
This is a very high-level view, to the point of not even mentioning things like action potentials and neurotransmitters.
With that said:
This is a very high-level view, to the point of not even mentioning things like action potentials and neurotransmitters.
With that said:
Humans (and our brains) are descended from an evolutionary lineage.
The earliest and most basic nervous systems probably consisted of small nets of neurons. We can still see these today in sea creatures called cnidarians (jellyfish, basically).
The earliest and most basic nervous systems probably consisted of small nets of neurons. We can still see these today in sea creatures called cnidarians (jellyfish, basically).
These nerve nets coordinate the internals of the organism, help sense what’s out there in the world, and facilitate movement (action). The basic ingredients are there.
By linking sensation and action, neurons make it possible for a tiny organism to sense something good, like food, and move towards it, or to flee from threats.
Here’s a little graphic from Peter Godfrey-Smith’s “Other Minds” that shows the evolutionary path between us and these early neurally-gifted ancestors.
So skip ahead a few dozen billion years and our brains, as part of our mammalian nervous system, have evolved to include billions of brain cells with trillions of connections.
The gifts of our lineage include “associative” brain areas, which allow us to organize information in complex ways,
as well as brain systems that give us things few or no other species have: speech, music, difficult mathematics, a unique kind of self-awareness.
as well as brain systems that give us things few or no other species have: speech, music, difficult mathematics, a unique kind of self-awareness.
The brain, as an organ, may have gotten preposterously complicated, but its core mission is still the same as the jellyfish’s:
survive!
survive!
It does this through something called “allostasis”, which is a fancy way of saying that the brain predicts what will happen to the body and adjusts its activity to keep things hunky-dory.
Would just like to highlight here that 
ALLOSTASIS IS REALLY IMPORTANT
(both for keeping you alive, and, IMO, for understanding FND)
ALLOSTASIS IS REALLY IMPORTANT(both for keeping you alive, and, IMO, for understanding FND)
Example: If you walk outside and it’s freezing, your brain doesn’t wait until you’re dying of hypothermia to go OH SNAP and do something about it.
It starts making changes right away - re-routing your blood flow, making you shiver - in anticipation of your upcoming needs.
It starts making changes right away - re-routing your blood flow, making you shiver - in anticipation of your upcoming needs.
As allostasis suggests, one of the most central, defining things about the brain is that it can change.
It can change itself structurally (that’s called neuroplasticity) and it can change how it behaves as well.
It can change itself structurally (that’s called neuroplasticity) and it can change how it behaves as well.
Some scientists now believe the way it implements these “functional” changes, these changes in how it acts, is through something called “prediction.”
Prediction (in neuroscience terms) is thought to be a kind of universal language of the brain. It’s what binds assemblies of neurons and allows them to coordinate as one big brainy ensemble.
Before explaining further let’s pause here to mark that PREDICTION IS THE OTHER THING THAT’S REALLY IMPORTANT
PREDICTION IS THE OTHER THING THAT’S REALLY IMPORTANT
So prediction allows brain areas to work together in teams, called brain networks. And it allows networks to work together to make up you.
In this view, your brain is a network of networks.
In this view, your brain is a network of networks.
There are brain networks for things like:
movement
vision
hearing
emotions (the limbic system, more on that later)
attention
and so on.
movement
vision
hearing
emotions (the limbic system, more on that later)
attention
and so on.
To recap this very important point,
::: the brain is an assembly of networks bound by prediction, organized around allostasis, because allostasis keeps you alive :::
::: the brain is an assembly of networks bound by prediction, organized around allostasis, because allostasis keeps you alive :::
Prediction guides both our motor abilities and sensory experience. It’s kind of the programming of our brains.
Anil Seth has a great talk about how prediction makes us accurately “hallucinate” our everyday reality: https://www.ted.com/talks/anil_seth_your_brain_hallucinates_your_conscious_reality?language=en
Anil Seth has a great talk about how prediction makes us accurately “hallucinate” our everyday reality: https://www.ted.com/talks/anil_seth_your_brain_hallucinates_your_conscious_reality?language=en
And here’s a favorite story of mine from Wired about Karl Friston’s theory of Active Inference, which explains more about action-predictions.
https://www.wired.com/story/karl-friston-free-energy-principle-artificial-intelligence/amp
https://www.wired.com/story/karl-friston-free-energy-principle-artificial-intelligence/amp
The big point here is that the brain uses prediction to change itself *based on past experience.* And it does that to help us survive.
OK, time to bring it together. One thing neuroimaging has shown is that in the brain, a certain level of coordination is required for good functioning and consciousness.
Makes sense! Good ensembles are defined by how well they play together.
Makes sense! Good ensembles are defined by how well they play together.
If brain areas fire all at the same time, (too coordinated), you basically have a seizure.
I’m not sure exactly what happens if no brain areas coordinate w each other, but given allostasis, I’d assume you’d, well, die.
I’m not sure exactly what happens if no brain areas coordinate w each other, but given allostasis, I’d assume you’d, well, die.
So getting the balance right is important. Less dramatic over-couplings and de-couplings are seen in all types of neurological and “mental” disorders, from Parkinson’s to PTSD. https://pubmed.ncbi.nlm.nih.gov/32800754/
All this proceeds w the influence of our individual genetics over the course of our development. Which I won’t get into right now because it’s almost time to have a snack.
So, to summarize “how the brain works”:
1. It’s first purpose is survival
2. Allostasis is at the center of brain function
3. It’s an ensemble of networks, in which balance is important
1. It’s first purpose is survival
2. Allostasis is at the center of brain function
3. It’s an ensemble of networks, in which balance is important
4. Prediction is a kind of algorithm that helps make allostasis possible
5. Genetics influence how you start out, how your brain develops, and how later events affect you in your life
5. Genetics influence how you start out, how your brain develops, and how later events affect you in your life
Part 2 of the thread ends here.
Thanks for reading this far, if you have.
NEXT UP: the final chapter
Knowing that stuff, what’s the case for FND as “the price of how our brain works?”
Thanks for reading this far, if you have.
NEXT UP: the final chapter
Knowing that stuff, what’s the case for FND as “the price of how our brain works?”
Ah, errata from this thread: evolution of the neural system happened over hundreds of millions of years, not billions. Yikes edits
