Course Notes: The Cerebellum

We have talked an awful lot about the prefrontal cortex and its significance to our performance in everyday life. But what about the back of the brain, like the cerebellum? Where’s the love for that neural region? Turns out that “little brain” found at the base of the skull right above the nape of neck deserves so much applause for what it does.

The cerebellum was the topic of my latest CEU course, so this post is going to get a little technical. But trust us, it’s worth the read.

For centuries, it’s been believed that the cerebellum was only responsible for unconscious motor movement, like balance and reflexes. Although that is true, it’s not its only job. Researchers are finding out more and more about how important and involved the cerebellum really is to our day-to-day operations and what happens when it goes awry.

With its Latin name meaning “little brain”, the cerebellum makes up 10% of the brain’s volume. However, it carries about more than 50% of all the neurons (nerve cells) in our entire body. With the more neural connections than any other part of the brain, the name doesn’t seem as fitting as it once did.

Cerebellar Circuitry

The cerebellum’s wiring throughout the brain, especially with the hippocampus (memory) and the prefrontal cortex (executive functions), allows for it to be an active member when learning new motor skills as well as repeatedly adjusting movement to appropriately interact with our environment.

The brain has a desire to make the “perfect plan” in the name of efficiency. Therefore, the cerebellum is constantly monitoring sensory intel to make automatic corrections without conscious thought. When we think about doing a task, our “big brain” sends a signal, and we move. Within 1/60 of a second, information is sent to the cerebellum on how we did it (Did we do it too fast? Too slow? Or just right under the current conditions?). The cerebellum then sends constructive feedback to the motor cortex to on how to better execute the action, based off past experiences of completing the same task. The motor cortex then transmits an updated command to modify the movement; thus, creating the most effective and efficient game plan.

Second Nature

How the cerebellum receives sensory input from the body is through Purkinje cells that are responsible for muscle memory (the ability to unconsciously reproduce a particular movement). These neurons encode information and store it so it becomes instinctive, allowing us to do things like walk, talk, or ride a bike without thinking.

Muscle memory is obtained through frequent practice and repetition of that movement. Before any action is committed to memory, it must first be learned. Learning new skills is a cognitive process and it takes a lot of time and energy to take in and process information to do a task. Once a skill is mastered, the cerebellum stores this motor blueprint to free up valuable cortical space needed for learning or adapting to novel situations. By storing learned movements, we can efficiently respond to situations in a split second.

Need an example? Think about the first time you were behind the wheel. We weren’t exactly driving like a scene from The Fast and The Furious, at least not at first. We had to learn how to operate the wheel, the pedals, the mirrors, and the radio all while watching the road and any pedestrians that dared to cross the street. Now, driving is second nature to us. We can take a call, maneuver through traffic, or drink coffee between lights without really thinking about how to operate the vehicle.

More Than Just Movement

The cerebellum has three lobes:

  • The anterior lobe (spino-cerebellum) – in charge of proprioception by receiving sensory information, knowing where our body and limbs are in relation to our surroundings
  • The posterior lobe (cerebro-cerebellum) – handles the cerebellar duties related to executive functions
  • The floculo-nodular lobe (vestibulo-cerebellum) – by receiving information from the inner ear, it coordinates eye gaze stability during head movement, hand-eye coordination, and smooth ocular pursuits

We associate the cerebellum to many motor functions like the coordination/quality of voluntary movement, muscle tone, and balance. However, many cerebellar functions are NOT for motor control. Other responsibilities include:

  • Learning. The cerebellum has connections to the prefrontal cortex; therefore, it is most involved when learning a new or complex skill. The more intricate the task, the more involved it is. It also plays a role in the efficiency of learning, like increasing speed, capacity, consistency, and appropriateness of our executive functions. Additionally, the cerebellum creates circuitry for implicit (or unconscious) learning. These are things that aren’t formally taught to us, but we know how to do, like understanding how close to stand/sit next to someone, picking up on nonverbal cues during a conversation, or using hand gestures when talking.

  • Timing and Rhythm. The cerebellum has an internal timing system that lets us know when to do an action to ensure fluid movement when doing an activity (hitting a ball, pouring milk into a bowl, etc). It helps us keep track of and manage our time. The cerebellum also establishes the rhythm/tempo/cadence of an activity (running, dancing, bouncing a ball).

  • Anticipation and Prediction. Because the cerebellum has receipts of every learned behavior and skill in its rolodex, it knows the outcome of every movement about 99% of the time. So if we a see a ball coming our way, our body will adjust to catch (or avoid) it. This also allows us to think fast when sudden changes occur (like the wind pushing the ball away from us) or to change body positions when anticipating movement (like bracing ourselves when the train comes to a full and complete stop). This is also useful during social interactions by “reading the room”, anticipating actions, and adjusting our behaviors accordingly. 

Small and Fragile

The cerebellum, for all that it does, is the most susceptible to structural malformation which can affect its function. This is because it undergoes a dramatic increase in growth between 24-40 weeks of gestation. That makes it extremely vulnerable to pre- and postnatal undernutrition and premature birth. Research has found that special populations (premature babies, ADHD, ASD, dyslexia) have smaller and less active cerebellums compared to typical children. This can result in:

  • Cognitive/behavioral/attentional/social difficulties
  • Difficulties with body awareness
  • Difficulties with self-regulation
  • Difficulties retaining learned motor skills, resulting in limited automaticity
  • Slower reaction times
  • Difficulties with balance and coordination
  • Difficulties with complex motor tasks
  • Difficulties with time management
  • Difficulties with procedural memory, affecting reading or writing

Move and Grow

Despite the cerebellum being the most fragile in the whole brain bunch, it is also the most plastic. This means that it can still grow and make the connections needed in order to function appropriately. Without knowing, you may already have been giving your child the opportunities to increase the connections in their cerebellum with movement, music, social interactions, and time outside to play and engage their body to learn and adapt.

In addition to these activities in our rhythm/timing post, you can also try:

  • Balance activities – balance boards/beam, standing on one leg, toe/heel walking, standing on dynamic surfaces while doing a task
  • Vestibular activities – swings, balance activities with eyes closed

The key to optimal functioning is to have the “big brain” and “little brain” together, allowing our kids to succeed in anything they do. Remember, if your kid is finding a new activity enjoyable, they will want to repeat it. That repetition is refining and honing the skills that the cerebellum will store for future use. This will also help them adapt to new situations and connect with peers, allowing our kids to grow into amazing adults.

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Williams, C. (2022, January 15). The Cerebellum and Development. Retrieved from Seminar.

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