026 The Function of the Cerebellum
In this video, Leslie describes the cerebellum and explains how it’s involved in coordination of movements.
Transcript of Today’s Episode
Hello and welcome to another episode of Interactive Biology TV, where we’re making biology fun! My name is Leslie Samuel. In this episode, I’m going to be talking about the function of the cerebellum. Inside this video, first I’m going to answer the question, “Where is the cerebellum?”, then I’m going to answer the question, “What does the cerebellum do?” Lastly, I’m going to talk about what happens when there’s damage to the cerebellum. So let’s get right into it.
Where is the cerebellum? Well, the cerebellum is right here. In the last video, we spoke about the cerebrum, and this is the cerebrum here. In one of the future videos, we’re going to talk about this part here, that’s the brainstem. So when we’re talking about the cerebellum, we’re talking about this portion here, kind of at the bottom and to the back of the brain, tucked away right here. That is where the cerebellum is.
Now, let’s answer the question, “What does the cerebellum do?” First of all, the ‘cerebellum’ is Latin for ‘little brain’, so that’s where it comes from. It’s involved in coordination of movement, in other words, motor control. It receives sensory input from the body, and then it coordinates the motor output. It’s involved in posture, precision, and accurate timing.
To illustrate this, let’s imagine that you’re trying to climb a flight of stairs. So here are our stairs. You’re trying to get to the top, and let’s say that this is you over here. Ooh, great drawing. I think I should quit teaching and start drawing for a living. Okay, let’s make you happy, and let’s make you not bald. There we go. So this is you, and you’re trying to get to the top of the stairs. Now, what does that involve? That involves coordinating the motion of your legs, and your legs are going to go from the bottom step to the next step. Now, let’s start going to the next step here, but we’re going to pause here.
When I’m at this point, there are a number of things that your brain needs to know. Your brain needs to know that you’re at this point, and your brain needs to know that you are trying to reach this point. So what the cerebellum does is it takes the sensory input. You get stimulation from your eyes, saying “Okay, I can see what’s going on here. I can see where the next step is. I can see where I am at this point.” Based on that, it can coordinate the motion of your feet and your legs so that you can reach to that point.
So it brings in sensory input about where you currently are, where the position of your body is, and it looks at where you’re trying to reach. And if there are any adjustments that need to be made, it makes those adjustments.
If you’re at this point and, for example, the brain thinks that you’re at this point, the brain is going to try to get you to go down. What’s going to happen is you’re going to trip and fall. We don’t want that to happen, and fortunately, we have a cerebellum at the back of the brain that coordinates that taking input and motor output.
Let’s talk a little bit about what happens when there’s damage to the cerebellum. The cerebellum doesn’t cause motion, but it just coordinates it. So if there’s damage to the cerebellum, movement is still possible. However, it’s going to cause disorders in fine-motor control, posture, and motor learning.
For example, in the scenario that I just drew, if you’re trying to climb the stairs and the brain does not know exactly where your foot is, so it can’t really calculate how far you need to go, it can cause problems with you walking up the stairs. It can also cause jerky movements because the cerebellum is not able to fine-tune that motion and coordinate it in the way that it normally does.
That’s it for this video. In review, we’ve answered the question, “Where is the cerebellum?”, and then we answered the question, “What does the cerebellum do?” Lastly, we looked at what happens when there’s damage to the cerebellum. That’s it for this video, and I’ll see you in the next one.