I hope you all are ready to help me welcome #NeuroThursday back in action this week with a story about how you stay balanced - and the amazing things you accomplish with that ability!
This topic was requested by the illustrious @KJKabza, who wondered: "Are there special strengths of the human balance system (we all know that it is easily disrupted if you spin around)?"
Yes, KJ, oh yes. Your balance system is doing highly badass things all the time, quietly under the hood while you go about your life. Like the devil, its best trick is making you think it's not even there.
So what is this balance system? Mostly it's the "vestibular system," a set of tiny organs in your inner ear that detect movement of your head. Neaby the ear-bits that pick up sound, but distinct.
(For non-head balance, you have another sense, called proprioception - a distributed sensory system that detects your body position. But that could be a topic for another day!)
This handy Wikipedia image shows the layout well. The important parts are the Semicircular Canals/Ducts (3 rings in the organ's upper-left) and the Utricle and Saccule (blobs in middle). The snaily bit below is for hearing.
The semicircular canal & utricle/saccule all follow the same principles. They're filled with Goop, and when the goop moves, it bends tiny hair cells. The hair cells are neurons, and they activate when bent. Bam!
How the canals work: imagine spinning a hula hoop full of water - the water lags behind a bit. The hair cells are attached to the rim, so from their little POV the water is flowing past them, and they bend in the current.
These canals are for detecting rotation: if I just shove my hula hoop around (instead of spinning), it's not gonna work. You have multiple canals in different orientations so that you can detect head rotation in any direction.
The semicircular canals are the part that get out of whack if you spin around too much! Put too much velocity in the water and it'll keep going and going and going even after you stop spinning the hula hoop.
The utricle/saccule are simpler. Goop is full of tiny crystals. Linear acceleration will jostle the crystals & thus the hair cells.
Whew that's enough anatomy. But now you know how we detect head motion. Ok please stand up and spin around until you understand this system's flaws. I'll wait.
Seeing straight yet? No rush, I'll be here. C'mon! You know you want to!
Okay anyways. Now you definitely know the flaws in this system. But it's allowed to have some flaws because it is SO GOOD. Let us demonstrate. (No seasickness this time, promise.)
You can do the demo with this text if you're reading on a laptop/phone. If you're twitterizing from a desktop computer, grab a book.
As you read this tweet, shake your head back and forth. Start slow, as if saying "no thanks" to this demo, then build up speed. You should be able to move pretty fast and still read this tweet.
Now hold your head still, and shift your screen back and forth instead.
Hahaha no you can NOT read while your screen/book is shaking back and forth. Why the difference? VESTIBULAR SYSTEM, BABY.
Down in your brainstem, your vestibular system connects to your eye-movement system. That connection lets your eyes compensate automatically for your head movements.
If this were easy to do, you could read while shaking your book! But it's gotta be perfect, and you can't pull that off alone.
If you want to be a goofball, test this in the mirror. Watch your eyes while you move your head around! You can hit a limit somewhere, but generally it's a perfect match.
This is your vestibular system's magic: it lets you tell what head movements you make, and compensate for them to keep your visual field fixed. Super useful for every activity that involves looking at things without holding your head stock-still.
Which is, really, most things. But if you wanna invent an evolutionary explanation, we can spin a story about keeping that visual field unmoving so you can detect actual real motion in the world.
When this system goes wrong, you get a condition called nystagmus: uncontrolled movements of the eyes, as if it always thought you were aspin. Awesome creepy video ahoy!
So here's your #NeuroThursday takeaway: your balance system is SO GOOD, you never notice all the hard awesome work it does keeping your gaze where you want it.
(And by "you," I mean the typical human. Maybe not you personally! That's cool, you do you! But if not you, maybe ask your doctor – or check out the Vestibular Disorder Association vestibular.org )

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Benjamin C. Kinney (mostly on Bluesky & Mastodon)

Benjamin C. Kinney (mostly on Bluesky & Mastodon) Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @BenCKinney

Aug 13, 2018
Handedness comes in two groups, "right handed" and "not right handed." Most people use their right hands for almost all precision movement, but the other group is a broad spectrum from weakly-right to strongly-left. baen.com/handedness
The way we describe and define handedness creates the effect @CStuartHardwick rightly notices. Culture defines how we talk about it - but the behavior is mostly genetic. The % of righties has remained constant across continents and milennia.
Hand dominance is a more squirrelly thing than most people realize. For example, righties are better at *some* things with their left hand... and *some* of these asymmetries flip in lefties. Take a few minutes on #LeftHandersDay to learn more!
Read 4 tweets
Aug 8, 2018
Quick heads up on the #BlackSpecFic report: the story counts for @escapepodcast @Pseudopod_org and @PodCastle_org are incomplete, and revisions will be forthcoming.
But you should read and learn from the #BlackSpecFic report anyways! The missing data is due to idiosyncrasies of the @EAPodcasts model, and has no impact on any other magazine's numbers.
Long story short, we treat reprints very differently from other magazines. For @escapepodcast specifically, they were ~45% of our 2017 stories, and our editorial process has one unified pipeline for originals + reprints together.
Read 4 tweets
Jul 23, 2018
Regretting organizing my two Worldcon panels this year. It means I'm not free to throw up my hands in frustration and give up on programming. The last 24hrs have been the last worst icing on a bad cake that's long been baking.
I mean, my panels will be awesome. But if you're skipping programming because you don't trust the con, you've made a sensible choice.
There are always more people who want to be on programming than can fit. There's no way to make everyone happy. I get that. But this weekend's screwups come in the context of a long chain of trust-erosion.
Read 4 tweets
Jul 13, 2018
So glad this one came out! "After Midnight at the Zap Stop" by @ouranosaurus is an awesome story - full of late-night grease, and the luckless & the worthy. But also because it's a #neuroscience teaching opportunity. Might even be a #NeuroThursday!
One offhand line explains a technology as "stimulating a particular set of mirror neurons." Which works as a story element just fine. It sounds plausible and authoritative! But as a neuroscientist, I have strong opinions about #mirrorneurons. I don't think they're real.
To be clear, mine is a controversial opinion. Many neuroscientists would disagree. But it's a hill I'm willing to fight on, especially given how often "mirror neurons" crop up in popular science.
Read 14 tweets
Jul 8, 2018
This Lindsey Sterling + Evanescence concert has been going for 3 minutes and it is already amazing.
Update: she is simultaneously dancing, playing violin, and kicking skeletons.
P.S. She too is a skeleton. Hard to be sure at this distance but I believe she has glittery bones.
Read 14 tweets
Jul 4, 2018
This phenomenon - when you look away from a moving thing, and you briefly see illusory motion in the other direction - is the "Motion Aftereffect," and it comes from some very basic brain maneuvers. Who wants to join me on going full #NeuroThursday here? en.wikipedia.org/wiki/Motion_af…
Most neurons in the brain (and elsewhere) do this thing called "adaptation," where they accept whatever's going on as the new normal. For example, if you sit down with your laptop on your lap, you'll soon stop noticing the weight.
This can arise from the crudest single-cell level: some ion channels in the cell membrane have negative feedback loops that self-dampen.
Read 14 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!


0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy


3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us on Twitter!