Rachel Gottlieb-Smith, MD, MHPE Profile picture
Apr 15, 2022 10 tweets 6 min read Read on X
1/🧵
What’s going on in the 🧠 that causes motion sickness – and what’s the link with #migraine?

A #tweetorial about motion sickness, the importance of matching, and why serotonin matters

#MedTwitter #NeuroTwitter
2/
First, let’s review some structures of the vestibular system that help us sense body movement:

1⃣ Semicircular canals = angular acceleration
2⃣ Otoliths (utricle & saccule) = linear acceleration & head tilt

📷: cell.com/current-biolog…
3/
The 🧠 combines this vestibular input with visual 👀 & proprioceptive input to assess motion

➡️ This is where the importance of matching comes in

...So what happens when the inputs don't match?
4/
'The neural mismatch theory' = 🧠 receives conflicting info from vestibular, visual & proprioceptive systems

2 main categories of mismatch:
1⃣ Semicircular canals v. otoliths
2⃣ 👀 v. vestibular/proprioceptive

pubmed.ncbi.nlm.nih.gov/23615033/
5/
Example of semicircular canal v. otolith mismatch: 'vestibular coriolis' reaction*

*The fancy term for what happens if you're spinning in a chair in a horizontal plane and move your head along another axis (like forward or backward)

pubmed.ncbi.nlm.nih.gov/23615033/
6/
Example of 👀 v. vestibular mismatch: reading in a car

Your 👀 tell you you're not moving, but your vestibular system says otherwise

...All of these can lead to the classic symptoms of nausea/vomiting, pallor, cold sweats
7/
Motion sickness is particularly common in kids, and we often see it as a precursor to #migraine

What's the 🔗?

There are a few ideas, including a hypersensitive vomiting center & central hypersensitivity, and some interesting observations involving serotonin
8/
🔽 tryptophan - a precursor to serotonin - 🔼 motion sickness in controls, similar to others w/ migraine
pubmed.ncbi.nlm.nih.gov/16116130/

& pretreatment w/ rizatriptan - a serotonin (5-HT1) receptor agonist - 🔽 motion sickness in people w/ migraine
pubmed.ncbi.nlm.nih.gov/20862509/
9/
So serotonin may help with motion sickness!

(But somehow I don't want to personally test this on Thanksgiving after eating lots of tryptophan...)
10/
In summary, 2 major ideas:
💡 A theory behind motion sickness: 'neural mismatch theory' = conflict between vestibular, 👀, & proprioceptive systems
💡 Low serotonin may be a connection between #migraine and motion sickness

• • •

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More from @RGottliebSmith

Jul 8, 2022
1/🧵
Ever look at an #EEG & wonder what the 🧠 squiggles mean?

This #twEEGtorial is for you

#MedTwitter #NeuroTwitter #EEGTwitter #Tweetorial
2/
Let’s start with some background:

💡 #EEG = electroencephalogram
💡 What an EEG does: records electrical activity in the 🧠
3/
You might then 🤔: how does the 🧠 create ⚡️?

A bit of neuroscience: 🧠 cells called neurons generate ⚡️ through the flow of charged ions (sodium & potassium) across their membranes

An EEG on the scalp can't detect the ⚡️ of a single neuron, but can when neurons are in sync
Read 16 tweets
May 21, 2022
1/
The only good thing to come of finding this on my leg last week: I learned enough to write a #tweetorial about it

A 🧵/twitter PSA about what to do if a tick comes for you – & what neuro presentations you can see w/ tick-borne illnesses

#MedTwitter #NeuroTwitter #IDTwitter
2/
After time outside in a non-wooded area, I found this on my leg. I didn’t realize what it was, so I grabbed it & flung it off... only to then find a very active, crawling tick on my counter. 😱

So after freaking out for a moment (or 2), I had to figure out what to do with it.
3/
Memories from med school flashed into my head of what you’re SUPPOSED to do:

1⃣ Remove tick w/ tweezers
2⃣ Grab close to skin & pull tick off without twisting so it doesn’t break apart
3⃣ Disinfect

Since I had already accidentally messed up 1⃣ & 2⃣, I started w/ 3⃣
Read 17 tweets
Feb 13, 2022
1/
#MedTwitter: ever learn a mnemonic that you can’t remember 5 minutes later? 🙋‍♀️

What makes a mnemonic useful (or not)?

A 🧵 about the good – and the bad – of mnemonics

#MedEd #NeuroTwitter #Tweetorial
2/
First, some background:

Mnemonic = relating to memory

Mnemonic devices/techniques (often called mnemonics for short) = memory aids or strategies that help with recall

Goal: transition info from working memory to long-term memory (and then be able to retrieve it later!)
3/
Let’s review 3 mnemonic techniques:

1⃣ Method of loci AKA “memory palace”
▪️ Type of imagery mnemonic
▪️ Info mentally placed at important landmarks along an imagined path ➡️ recall by re-tracing the route
▪️ Vivid images are helpful

Image from pubmed.ncbi.nlm.nih.gov/33613393/
Read 11 tweets
Feb 3, 2022
1/12
How does botulinum neurotoxin (BoNT) work to improve chronic migraine? 🤔

⚡️ Spoiler: it's probably not what you think!

A 🧵 about BoNT & #migraine

#MedTwitter #NeuroTwitter #tweetorial
2/
Let's start with a definition: what makes a migraine "chronic?"

◾️ Headache occurs at least 1⃣5⃣ days per month
◾️ Of which at least 8⃣ have features of migraine headache
◾️ For 3⃣ months or more

From: Int'l Classification of Headache Disorders ichd-3.org/1-migraine/1-3…
3/
And a bit of history: botulinum neurotoxin (BoNT) came to be studied for chronic migraine after anecdotes suggested that BoNT injections to treat wrinkles also helped with headaches!
Read 12 tweets
Jan 22, 2022
1/
What's the best strategy for effective - and time efficient - teaching in clinic?

A 🧵 for 4⃣ teaching strategies when 🕗 is limited (& how they might be used in #neurology)

#MedEd #NeuroTwitter

pubmed.ncbi.nlm.nih.gov/18276715/
pubmed.ncbi.nlm.nih.gov/29383053/
2/
1⃣ One-minute preceptor (initially called: 5-step microskills)
pubmed.ncbi.nlm.nih.gov/1496899/

5 steps & examples 👇

Pros:
✅ Assess learner's knowledge
✅ 👍 & constructive feedback "built in"
✅ Clinical reasoning
✅ Good for novice learners

Cons:
⛔️ "1 min" is a bit unrealistic
3/
2⃣ SNAPPS
pubmed.ncbi.nlm.nih.gov/14507619/

Pros:
✅ Very learner-driven
✅ Aligns well w/ traditional presentation model
✅ Clinical reasoning

Cons:
⛔️ May not work as well for novice learners
Read 7 tweets
Jan 13, 2022
1/🧵
What's your favorite anti-seizure medication (ASM)?

If you said levetiracetam (LEV), you're not alone.

Why do so many #neurologists ♥️ LEV? A #tweetorial.

#MedStudentTwitter #NeuroTwitter #MedTwitter @MedTweetorials
2/
What's so good about LEV? First, some #pharmacology:

✅ Fast PO absorption
✅ 1:1 PO:IV 💉
✅ Few med interactions
✅ Can load for status epilepticus

pubmed.ncbi.nlm.nih.gov/31029217/ Image
3/
And lots of clinical uses:

1⃣ Focal and generalized seizures
2⃣ From 👶 to 🧓
3⃣ Often used in 🤰 (category C): pubmed.ncbi.nlm.nih.gov/28472982/
4⃣ Good for status epilepticus (60 mg/kg, up to 4500 mg) - similar efficacy to phenytoin & valproic acid:
pubmed.ncbi.nlm.nih.gov/32203691/
Read 9 tweets

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