Internuclear Ophthalmoplegia | INO | Animation | Explained Conceptually
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- Опубліковано 17 лип 2024
- Part 1 of an animated analogy to explain how the horizontal gaze pathway works and how it can get damaged to cause an Internuclear Ophthalmoplegia (INO)
Timecodes
0:00 - Intro
0:34 - Conjugate horizontal eye movement
1:08 - Analogy breakdown
1:26 - Saccadic vs pursuit movement
1:54 - Paramedian Pontine Reticular Formation (PPRF)
2:21 - Abducens nucleus motor neurons
2:37 - Abducens nerve
2:42 - Lateral rectus muscle
2:50 - Abducens nucleus interneurons
3:25 - Medial Longitunidal Fasciculus (MLF)
4:10 - Medial rectus subnucleus
4:29 - Medial rectus subnucleus motor neurons
4:33 - Medial rectus muscle
5:21 - Horizontal eye movement mechanism
7:00 - Left Internuclear Ophthalmoparesis
7:44 - Right Internuclear Ophthalmoparesis
8:25 - Right Internuclear Ophthalmoplegia (INO)
8:49 - Dissociated ABduction nystagmus
9:38 - Left Internuclear Ophthalmoplegia (INO)
10:02 - Terminology: Internuclear, Ophthalmoparesis & Ophthalmoplegia
10:41 - Bilateral Internuclear Ophthalmoplegia (BINO)
11:07 - Pseudo-INO
11:31 - Convergence
12:15 - Summary
#EndNeurophobia
I hope you found this analogy helpful :)
If you have any ideas for neurology concepts you would like an animated analogy for, let me know below and I'll add them to my list!
this is one of the best explanations I've found about this topic! Thanks so much!
Glad it was helpful!
I can say only one thing...
Superb, nothing else
Thank you for the kind words
This is pretty good, keep up the good work. Try increasing your video count ,then maybe post it on groups with large followings like USMLE, or MRCP groups. I'm sure you'll do really well.
Thanks for the kind words Francisco :)
Awesome, simply the best explanation, so far, really don’t know how I found your channel but I did, thank you ❤❤❤❤❤❤
Glad it was helpful!
Amazing explanation. Thank you
You're most welcome, thanks :)
Fantastic!
Glad you like it!
Great lecture!
Thank you for your appreciation :)
Perfect❤❤❤❤❤
thank you for the kind words Uday :)
thank you!!!!!!!
You're welcome!
I have subscribed, liked and shared ❤❤❤❤❤❤
Very kind of you :)
Is INO the same as 'lazy eye'.. and more importantly can INO be corrected (new connections made?), via eye exercises (Crossing eyes, patch, etc) or supplements (Vitamin-D/A, etc)?
If not, is surgery and/or procedures (stem-cells, tetrodotoxin, etc) available for this condition? Is there any doctor(s)/hospital(s) that have become the go-to for INO?
About a year ago, my *RIGHT* eye suddenly could not move past the mid/center point... fortunately, full range eventually came back after a few months. Unfortunately, now the *LEFT* eye is not tracking with the right eye, even though it can correctly move anywhere if the right eye is closed.
Both the previous and now this new issue, seem related to the Rostral / midbrain.
Thanks Ben for the question. INO is not the same as a lazy eye. Lazy eye (amblyopia) is normally due to peripheral causes affecting the eye itself or the extraocular muscles, which over time if left untreated, makes the brain ignores vision from that eye. INO is due to an MLF issue, for which could be due to stroke, MS, tumour etc. INO is not a condition, only a sign of where damage is. Treatment is for the underlying condition, and may not go away.
I can't give specific medical advice on UA-cam, but based on your experience I would recommend seeing a doctor/Neurologist.
Why would the damage to the MLF affect the communication between the ipsilateral sixth and contralateral third cranial nerve nuclei? If the Left MLF gets damaged, communication breaks down between the Left third cranial nerve nuclei and the Right sixth cranial nerve nuclei. So, shouldn't it be ipsilateral third and contralateral sixth cranial nerve nuclei?
Thanks for the question, Ya Mone. In short, it's a question of semantics. There's so no hard-and-fast rule, but in general, as the impulse goes CN6 → MLF → CN3 (not CN3 → MLF → CN6), it is fair to say that CN6 is ipsilateral, and CN3 is contralateral. Recall that the MLF is named according to where it goes; i.e. left MLF begins on the right, then goes to the left. Hope this helps.
@@NeurologyAnalogy Does this mean that ipsilateral or contralateral is decided based on the beginning of the MLF and not according to the name (where it goes)?
It depends where the lesion is; if the MLF is damaged close to the left CN3, then left is ipsilateral to lesion, and right contralateral. If MLF is damaged close to right CN6 before it decussates, then right is ipsilateral to lesion, and left is contralateral. Hopefully makes sense
@@NeurologyAnalogy that makes sense. thanks a lot for the explanation!
Why can’t you make slow pursuit eye movements without focusing on an object, only saccadic scans? Great video, thanks
Or being unfocused for that matter
Hey Steen, this is because of the differing functions of the saccadic vs the smooth pursuit mechanism.
TL;DR: Saccades are fast movements to look at stationary targets. Smooth pursuit helps you follow moving targets
If a target is stationary and you want to suddenly shift your gaze to look at it, it is better to use fast saccadic movement to quickly orientate the target to fall onto your fovea, rather than use the slow pursuit mechanism which would take too long. It makes sense that you quickly move the eyes as you already know where it is that you want to look ahead of time (i.e. before your eyes begin to move).
If a target is moving, the smooth pursuit mechanism ensures that the moving target continues to fall onto your fovea, regardless of its direction. As you are following a target in real-time, you do not know ahead of time where your eyes should move next, and so you need a mechanism to smoothly follow the target. if you followed target with saccadic movement, the eyes might undershoot or overshoot the moving target, which means you would have times when the target is not directly falling onto your fovea.
Hope this helps answer your question
Great video!!! Beautifully explained. Thank you 😀
@@NeurologyAnalogy Does INO behave differently depending on if you use the smooth pursuit vs saccade mechanism? I'm guessing no but correct me if I'm wrong
@@Vocaloidict Great question, and you're right - there's no difference because the final common pathway for saccades and pursuit is the CN6 nucleus, which uses the MLF. So regardless of saccades or pursuit, you would see an INO, but to best see an adduction lag, better to use large amplitude saccades