The Cerebellum

Summary

In this video, Dr. Mike discusses the cerebellum's role in motor control. He explains how it fine-tunes muscle movements by comparing intended and actual movements, preventing overcorrection. Key functions of the cerebellum include muscle tone, coordination, balance, and posture. Anatomically, the cerebellum has three lobes: anterior, posterior, and flocculonodular. Functionally, it is divided into vestibulocerebellum for balance, spinocerebellum for proprioception and muscle tone, and cerebrocerebellum for skillful tasks. This overview highlights the cerebellum's critical role in precise motor functions.

Takeaways

• 😀 The cerebellum fine-tunes motor movement by comparing intended and actual movements, calculating errors, and adjusting accordingly.
• 💪 The cerebellum helps with muscle tone, coordination, balance, and posture.
• 🧠 The cerebellum sits inferior to the cerebrum, posterior to the brainstem, and in the posterior cranial fossa, separated by the tentorium cerebelli.
• 🌳 The cerebellum has a cortex and medulla, with a tree-like structure called the arbor vitae visible in cross-section.
• 🔍 The cerebellum is divided into three anatomical lobes: anterior, posterior, and flocculonodular.
• 🎢 Functionally, the cerebellum is divided differently: the flocculonodular lobe (vestibulocerebellum), the vermis and intermediate zones (spinocerebellum), and the lateral zones (cerebrocerebellum).
• 👂 The flocculonodular lobe deals with balance and receives information from the vestibulocochlear nerve (cranial nerve VIII).
• 🦵 The vermis and intermediate zones deal with proprioception, fine-tuning muscle tone and coordination for the trunk and limbs.
• 🎹 The cerebrocerebellum deals with fine motor tasks and receives input from the primary and secondary motor and somatosensory cortices, and the visual system.
• 📊 The cerebellum's divisions allow it to manage different aspects of motor control: balance and posture, coordination, and muscle tone.

Q & A

What is the primary function of the cerebellum in motor control?

The cerebellum fine-tunes motor movements by comparing intended movements with actual movements and adjusting for any errors. It is crucial for muscle tone, coordination, balance, and posture.

How does the cerebellum prevent you from overreacting when picking up an unexpectedly light object?

The cerebellum compares your planned motor effort (prepared for a heavy object) with the actual effort needed (for a light object) and adjusts the movement to prevent you from losing balance or control.

Can you describe the anatomical location of the cerebellum in the brain?

The cerebellum is located inferior to the cerebrum and posterior to the brainstem, situated in the posterior cranial fossa and separated from the occipital lobe by the tentorium cerebelli.

What are the three anatomical lobes of the cerebellum?

The cerebellum is divided into three anatomical lobes: the anterior lobe, the posterior lobe, and the flocculonodular lobe.

What is the functional role of the flocculonodular lobe in the cerebellum?

The flocculonodular lobe, also known as the vestibulocerebellum, is involved in balance and posture by processing information from the vestibular system (inner ear and cranial nerve VIII).

How is the cerebellum functionally divided based on its different regions?

Functionally, the cerebellum is divided into the vestibulocerebellum (balance and posture), the spinocerebellum (fine-tunes movements and muscle tone for the body and limbs), and the cerebrocerebellum (involved in planning and executing skillful, precise movements).

What is the role of the vermis and the intermediate zones in the cerebellum?

The vermis and intermediate zones, part of the spinocerebellum, are responsible for coordinating and fine-tuning movements of the head, neck, trunk, and limbs. They receive proprioceptive information to adjust muscle tone and movement.

What is the 'arbor vitae' and where is it located?

The 'arbor vitae' (meaning 'tree of life') is a distinctive branching pattern seen in a cross-section of the cerebellum. It refers to the cerebellar white matter that branches out from the brainstem into the cerebellum.

How does the cerebellum process information for fine-tuning complex motor tasks?

The cerebrocerebellum, the most lateralized part of the cerebellum, processes information from the primary and pre-motor cortex, as well as the somatosensory cortex and visual system, to fine-tune complex, skillful tasks like playing the piano.

What kind of sensory information does the cerebellum use to coordinate movements?

The cerebellum uses proprioceptive information (from muscles and joints), vestibular information (balance from the inner ear), and sensory information from the visual system and somatosensory cortex to coordinate and fine-tune movements.

Outlines

00:00

🧠 Introduction to the Cerebellum and Its Functions

Dr. Mike introduces the cerebellum, using a scenario where one anticipates lifting a heavy box that turns out to be empty. This example highlights the cerebellum's role in fine-tuning motor movements by comparing intended and actual movements to prevent physical mishaps. He outlines the cerebellum's primary functions: muscle tone, coordination, balance, and posture.

05:02

🔍 Detailed Anatomy of the Cerebellum

Dr. Mike delves into the anatomy of the cerebellum, explaining its position relative to the cerebrum and brainstem. He describes the cerebellum's structure, including its cortex, medulla, and the characteristic 'tree of life' (arbor vitae). The cerebellum is divided into three anatomical lobes: anterior, posterior, and flocculonodular, each with distinct roles.

10:03

🌐 Functional Divisions of the Cerebellum

Dr. Mike explains the functional divisions of the cerebellum. The flocculonodular lobe, or vestibulocerebellum, handles balance and posture via the vestibulocochlear nerve. The vermis and intermediate zones (spinocerebellum) process proprioceptive information, fine-tuning muscle tone and coordinating movements of the head, neck, trunk, and limbs.

🎹 Cerebrocerebellum and Its Role in Skillful Tasks

The cerebrocerebellum, located in the lateral regions, is responsible for fine-tuning motor tasks like playing the piano. It integrates inputs from the primary and secondary motor cortexes, somatosensory cortex, and visual system. Dr. Mike summarizes the cerebellum's functional areas, associating balance with the vestibulocerebellum, coordination with the cerebrocerebellum, and muscle tone with the spinocerebellum.

Keywords

💡Cerebellum

The cerebellum is a region of the brain that plays a crucial role in motor control, coordination, and balance. It is located beneath the cerebrum and posterior to the brainstem. In the video, the cerebellum is described as fine-tuning motor movements by calculating the error between intended and actual movements, which is essential for activities like lifting a box without flipping backward.

💡Motor Movement

Motor movement refers to the physical actions and gestures that the body makes, which are controlled by the nervous system. The video emphasizes that the cerebellum fine-tunes these movements by adjusting for any discrepancies between the expected and actual outcomes, such as when lifting a box that is unexpectedly lighter than anticipated.

💡Muscle Tone

Muscle tone is the natural state of slight tension in muscles when they are at rest. The cerebellum helps to fine-tune muscle tone, ensuring that muscles are neither too tense nor too relaxed, which is vital for maintaining posture and balance, as mentioned in the script.

💡Coordination

Coordination is the harmonious interaction of muscles and body parts to produce smooth and efficient movements. The video explains that the cerebellum is involved in fine-tuning this coordination, particularly in relation to the limbs, through its intermediate zones.

💡Balance and Posture

Balance and posture are maintained by the body's ability to maintain an upright position and stability. The script describes the cerebellum's role in these functions, particularly through the floccular nodular lobe, which is also known as the vestibulocerebellum, receiving information from the vestibular system.

💡Anatomy

Anatomy refers to the structure of living organisms and their parts. The video script provides a detailed anatomical description of the cerebellum, including its location, lobes, and the structures it is associated with, such as the cerebrum, brainstem, and the tentorium cerebelli.

💡Lobes

In the context of the cerebellum, lobes refer to the distinct sections that make up its structure. The script identifies three main lobes: the anterior lobe, the posterior lobe, and the floccular nodular lobe, each with specific functions related to motor control.

💡Vermis

The vermis is a central, ridge-like structure within the cerebellum that plays a key role in coordinating muscle tone and posture. The script explains that the vermis, along with the intermediate zones, forms a functional area of the cerebellum that receives proprioceptive information.

💡Proprioception

Proprioception is the sense of the relative position of one's body parts and the strength of effort being employed in movement. The video describes how the cerebellum uses proprioceptive information from the limbs and trunk to fine-tune motor movements and maintain balance.

💡Vestibulocochlear Nerve

The vestibulocochlear nerve, also known as cranial nerve VIII, is responsible for transmitting information about balance and hearing from the inner ear to the brain. In the script, it is mentioned that this nerve sends information to the floccular nodular lobe of the cerebellum, which is critical for balance and posture.

💡Cerebrocerebellum

The cerebrocerebellum is a functional region of the cerebellum that receives information from the cerebral cortex and is involved in the fine-tuning of complex motor tasks. The video script explains that this area is responsible for coordinating skillful movements such as playing the piano, which requires precise motor control.

Highlights

The cerebellum prevents flipping backward when lifting an object by calculating the error between intended and actual movement.

The cerebellum fine-tunes motor movement, muscle tone, coordination, and balance and posture.

Anatomically, the cerebellum is situated inferior to the cerebrum and posterior to the brainstem.

The cerebellum has a similar structure to the cerebrum, with gyri, sulci, cortex, and medulla.

The arbor vitae, a tree-like branching, is a distinctive feature of the cerebellum.

The cerebellum can be anatomically divided into three lobes: anterior, posterior, and flocculo-nodular.

The flocculo-nodular lobe is functionally distinct and primarily deals with vestibular movement and balance.

The flocculo-nodular lobe is also known as the vestibulo-cerebellum, receiving information from the vestibular system.

The vermis and intermediate zones of the cerebellum have a topographical map of the body for fine-tuning coordination.

The vermis is responsible for fine-tuning muscle tone of the head, neck, and trunk.

The intermediate zones are responsible for coordinating the musculature of the limbs.

Proprioceptive information from the limbs and trunk is processed in the intermediate and vermis regions.

The spino-cerebellum processes information from spinal nerves related to muscle tone and coordination.

The cerebro-cerebellum is involved in fine-tuning complex motor tasks and receives input from the cerebral cortices.

The cerebro-cerebellum integrates information from the primary motor cortex, pre-motor cortex, somatosensory cortex, and visual system for skilled motor tasks.

The cerebellum's functional division includes the vestibulo-cerebellum for balance, the spino-cerebellum for muscle tone, and the cerebro-cerebellum for skilled tasks.

Transcripts

hi everybody dr mike here in this video

we're going to take a look at the

cerebellum

now to begin with i want you to think

about this scenario you're going to a

friend's place to help them

move they point to the corner of the

house where there's a box and they say

hey

can you pick that box up chuck it in the

truck for me now

they say to you look this box is heavy

so be careful now as you're walking over

to the box

you're thinking okay it's a heavy box

gonna have to utilize all my muscles

bend with my knees not with my back you

get over there

you grab the box and then you pick the

box up and you realize that the box is

actually

empty now what is stopping you from

flipping yourself backwards because you

prepared yourself to

pick up a really heavy box well the

thing that stops you from flipping back

is your cerebellum what the cerebellum

does is it takes

your intended movement and then it takes

the actual movement

and then it calculates the error between

those

two once it calculates that error it

then fine

tunes that motor movement so what the

cerebellum does is it fine-tunes motor

movement

and it does it through a couple of

different functions so

while it does fine-tune motor movement

you could divide

what the cerebellum does into it

helps fine-tune

muscle tone

coordination

and balance and posture

these are the main functions of the

cerebellum

muscle tone coordination balance and

posture now before we go into more

detail about the function

let's talk about the anatomy a little

bit so the cerebellum we've drawn up

here we've got the cerebrum

which is the main part of our brain our

two cerebral hemispheres

this is a lateral view so we've got the

cerebrum we've got the brain

stem which is midbrain ponzo medulla and

we've got the cerebellum

sitting here so you can see the

cerebellum sits inferior to the cerebrum

posterior to the brain stem and the part

of the scale that it sits within

is the posterior cranial fossa and it's

separated

from the occipital lobe of the cerebrum

by the tentorium

cerebellar so if we were to take the

cerebellum and the brain stem

and pull it out and have a look at it

we've performed a sagittal view so we're

looking into it from the side from a

lateral view

and we can see a couple of things

firstly it is

folded like the brain like the cerebrum

itself so it does have these gyri and

sulci you know bump up dips down and so

forth

it does have a cortex and outer region

and a medulla again

like the cerebrum but a couple of things

is that if you were to look at it

under a section there looks like there

is a branching like a tree that comes

out

from this aspect of the brain stem and

that's called the abervite which means

tree

of life now you can also see we've got

the brain stem here with the midbrain

pons and the medulla and you can see

part of one of the ventricles

here so if you were to divide the

cerebellum up

anatomically you can divide it into

three lobes so

these three lobes

first of which we've got the anterior

lobe

second

is all this here is the posterior lobe

and then this lobe underneath here this

is called the flow

nodular lobe great name isn't it

floccula

flocculo nodula

lobe these are the three anatomical

lobes you can see the floccular nodular

lobe sits underneath

so if we were to take the cerebrum a

cerebellum sorry and look at it from a

posterior view

like we've done here what we've actually

done is we've taken that flocculonado

lobe

and we've pulled it out so we can see it

so this is the floccular nodular lobe

here

the floccular nodular lobe

sitting under here now if we were to

find the anterior and posterior lobes

we could very roughly

separate them out like this where we've

got the anterior

and posterior lobes

now again these are anatomical divisions

right one two

three but if we were to look at it

functionally you can actually separate

the cerebellum a little bit differently

firstly we're going to begin with the

floccular nodular lobe and the reason

why is because

the flocculation nodular lobe

anatomically is distinct but also

functionally it's quite distinct and the

reason why is because

it deals predominantly with

vestibular movement so this is referring

to

the vestibular system so balance

so i want you to think about the

vestibular system

information coming from the vestibular

cochlear nerve right from the inner ear

this is

cranial nerve eight so information

coming from your balance areas of your

inner ear

is sending information to the floccular

nodular

lobe so i could draw up an arrow here

and say that information from cranial

nerve eight

which is the vestibulocochlear nerve is

going to the flocular nodular lobe and

so another name for this area

is the vestibulo cerebellum so this can

also be recognized as the

vestibulo cerebellum

vestibulo

cerebellum and what does it deal with it

predominantly if it's going to be

cranial nerve 8 it's going to be dealing

with balance and posture what did i say

balance and posture so let's write this

down i'll just write balance

okay now when we move up

what you're going to find is that when

we are to break these

anatomical lobes the anterior and

posterior up into their

functional areas we don't do it in this

way we actually do it in this

more vertical way and this is how it

works firstly you can see that there's

two hemispheres of the cerebellum

and it's separated out or connected by

this area in the middle called the

vermis

so let's actually label that

the vermis

now importantly the vermis and its areas

immediately next door

which are called the intermediate zones

into immediate

zones the vermis and the intermediate

zones

are its own functional area right now

let me tell you why because

there is actually a topographical map of

the body placed on the vermis and the

intermediate zones

just like we've got the somatosensory

homunculus and motor homunculus

on our cerebellum we have a homunculus

on the vermicent intermediate side so

let's have a look

what we've got is it looks a little bit

like this

a little bit like an alien

it's upside down right and hear the eyes

now we've got one here as well in this

position

so what can you see first thing is the

axial

musculature so the musculature of the

neck

and the trunk the head neck trunk for

example all lies within the vermis

so that means when it comes to

fine-tuning coordinating muscle tone

of the head neck and trunk it's all

coming from the vertice when we deal

with coordinating and fine-tuning

the musculature of the limbs this is all

coming from the

intermediate zone right that's important

okay another thing is that information

we said information coming from the

vestibular cochlear nerve is going to

here to deal with balance

information coming from these parts of

the body this is going to be

proprioception

right so telling you where your arms are

in their space telling you

how bent a joint is telling you how

contracted a muscle is

all this type of proprioceptive

information from the limbs

intermediate zone and from the trunk

head neck and trunk

vermus it's coming from the

proprioceptors to these areas

right so i can draw up an arrow and say

proprioception

so proprioception is going to these

areas here

for the limbs there and for the head

neck and trunk there

all right now well the other thing is

that

this focular nodular zone is also known

as the vestibulocochlear

vestibulocerebellum this area has

another name it's called the

spinocerebellum because

it's all coming through the spinal

nerves to go to these areas

right so let's rename it

the spino

cerebellum

the spinous cerebellum is also this area

here including the vermice and

intermediate zones

all right the last area are these most

lateralized

areas and these most lateralized areas

i'll first give you the name

is called cerebro

cerebellum and that should tell you

where it's getting its information from

it's getting it from the cerebrum from

the cerebral cortices

so this area deals with very very

fine tuning of motor information

skillful tasks playing the piano

doing very important tasks like that

right there very skillful tasks so what

we find

is that information coming in to

these most lateralized regions are

coming from

the primary

motor cortex

the pre-motor cortex

now together you've got planning and

actually thinking about doing

that motor movement that's coming in

here so it can be fine-tuned right

it's going to have information coming in

from the primary

and secondary somatosensory cortex

so information about sensation

this is important because we need to

know information about the musculature

and of the body

in order to make a decision and

information

coming from the visual system

specifically about

objects that are moving in our vision is

all coming into this cerebro cerebellar

these lateralized areas all right really

important

so overall what we're going to find is

this

i said balance and posture vestibulo

cerebellum

coordination is going to be

mainly here

because it's really skillful tasks right

coming from the motor pre-motor

somatosensory visual

and tone how contracted or relaxed the

muscle is

is going to be coming from the vermis

and intermediate zones and so we can pop

tone in this area here

and this is how we can functionally

divide the cerebellum

so hopefully this gives you a nice

summary of

the anatomy of the cerebellum and the

physiology