The Cerebellum
Summary
TLDRIn 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
🧠 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.
🔍 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.
🌐 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.
Mindmap
Keywords
💡Cerebellum
💡Motor Movement
💡Muscle Tone
💡Coordination
💡Balance and Posture
💡Anatomy
💡Lobes
💡Vermis
💡Proprioception
💡Vestibulocochlear Nerve
💡Cerebrocerebellum
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
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