Yoked End Organs, Part 1

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来自 The University of Chicago 的课程

了解大脑：日常生活中的神经生物学

607 个评分

The University of Chicago

了解大脑：日常生活中的神经生物学

607 个评分

Learn how the nervous system produces behavior, how we use our brain every day, and how neuroscience can explain the common problems afflicting people today. We will study functional human neuroanatomy and neuronal communication, and then use this information to understand how we perceive the outside world, move our bodies voluntarily, stay alive, and play well with others.

从本节课中

The Vestibular Sense & Gaze

The vestibular system and gaze control give us so much but are grossly under appreciated. They are so fundamental that we discount them, assuming that they will always be there. When the vestibular system fails us, its importance dominates our lives. Living with either a vestibular or an eye movement disorder is very disruptive to everyday life. In this module, you will learn how the inner ear is designed to detect and respond to head movements. You will learn about the circuit that connects the inner ear to the motoneurons that control the location of your eyes, allowing us to reflexively maintain our view of an object even as we move about in the world. Finally, we will talk about how you can modify this reflexive control of the eyes and how you can control where you are looking.

Hair Cell Orientation6:00

Yoked End Organs, Part 15:27

Yoked End Organs, Part 23:47

Otoconial Disorders5:54

Visual Integration3:44

与讲师见面

Peggy Mason
Professor
Neurobiology

[MUSIC]

Okay, so what we looked at in the last segment was how an individual end organ,

and end organ means either a semicircular canal or orniconial mass.

How the hair cells work in in one of those.

Well, in fact, our head is, is, is one head so

there are pairs that are going to get exactly the same stimulus.

And they're going to work together so let's figure out what those pairs are.

We're going to look at the first at the semicircular canals and

there are three on each side.

We talked about dividing the planes of rotation into three.

And they exist on both sides.

Well, if there is a rotation in this yaw plane.

This is the yaw plane saying no.

That's yaw.

I'm rotating in the yaw plane.

Well, it will affect this canal and this canal.

So whatever happens over here, the opposite is going to happen over here.

They are a yoked pair, the horizontal canals.

These are called the horizontal canals, and the left and

right horizontal canal, they're yoked.

So there is no normal circumstance under which they would

get a anything but opposite inputs.

So they couldn't both be excited, they couldn't both be inhibited

and one can't be excited without the other one being excited.

So they have, they're yoked, they're always in opposition.

Now, this, these, this interior canal and

this posterior canal, they're also in the same plane.

They're in this plane.

So they're a yoked, they're a yoked pair, and similarly, this canal,

the anterior canal on the left side and the posterior canal on the right side,

they're yoked, so they're in the same plane.

Alright, so.

What?

Look. What does that mean?

Let's go over to the board for a second and

I've just redrawn what I said on the tablet right here,

but now let's take a side view and let's realize that there's a,

there's also a a top-down orientation to this.

So the anterior canal is here, posterior canal is here, horizontal canal is there,

the hair cells are located here,

here, and here.

So lets think about what happens when somebody drinks a lot of alcohol.

Well with alcohol intoxication, one of the things that happens is that the copula,

which gets a blood supply of its own, it actually gets really light.

It's light with alcohol, and it floats up.

And so as a result of floating up, it can for instance

stimulate the hair cells on, in the posterior canal.

But not just the hair, the posterior canal but

also say the anterior canal, and also the, the horizontal canal.

And it can stimulate these hair cells in very non-normal

patterns not just on the, on the, on one side but on both sides.

And so all of a sudden what you're getting is this signal

that makes absolutely no sense.

It, there's no physical acceleration that could lead to this

to this signal that you're getting from your vestibular end organs.

So when would this happen through evolution?

Well it would happen if you ate something

that really messed with your blood chemistry.

And so perhaps for that reason, this is the,

the best reason I can give you, whether it's true or not I'm not positive.

No one, no one really knows.

These are hard arguments to prove or disprove.

But the thought is that this, the, the mismatch,

this completely non-physiological signal that you're getting in is

simple interpreted as I ate something really bad, and now I need to go throw up.

And so, beyond having the sense of vertigo, things are spinning,

I'm spinning, the person with alcohol intoxication also feels nauseated.

And this is called the sensory mismatch hypothesis.

So the next segment we're going to talk about the yoked otoconial masses.

[MUSIC]

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