Brain basics: Movement, balance, and control

Have you ever noticed your foot moving on its own to stop you from falling? Or perhaps you’ve felt a sense of dizziness after stepping off a merry-go-round? This article talks about how this happens in the brain and unravels a way to avoid dizziness after coming out of the merry-go-round.

This post is also available in Dutch.

This blog is part of this year’s summer series called Brain basics, in which we dive into the general functions and development of our brains.

Cerebellum: the mini-brain.

Cerebellum resides on the back side of the brain. Despite occupying only 10 percent of the brain, the cerebellum contains about half of the total neurons in our body. It plays a vital part in movement, coordination, and balance. Its special organization helps in the speedy transfer of signals to the muscles which is useful for coordination. Further, it times the contraction of various muscle groups in synchrony and identifies the motion of oneself in the environment. For example, it can trigger eye movements based on how you move your head. The cerebellum has been shown to also be involved in attention, language processing and memory.

Image of the Cerebellum, which is located just below the cerebrum at the back of our heads and is involved in movement, coordination and balance. (Image created in BioRender)

Motor cortex: the motion planner.

The motor cortex is located in the middle part of the brain and is made up of 3 different areas. Together, these regions process sensory input form our environment and allow us to move our body within it. The primary motor cortex is responsible for the execution of voluntary movements, such as direction, speed and force. The pre-motor cortex receives inputs from various sensory areas, such as the visual and somatosensory cortices, allowing it to integrate sensory information relevant to movement. It is involved in activities such as reaching, grasping, manipulating objects, and correcting inaccurate actions. Finally, the supplementary motor cortex is involved in planning and coordinating complex movements, like motor planning, timing and order of movements. It also contributes to motor learning.

Image of the primary motor cortex which is involved in moving your body, premotor cortex which receives sensory input, and supplementary motor cortex which plans and coordinates our movements.  (source: the Neuroscience outline)

Vestibular system: the inertial sensor.

Although the vestibular system is not a specific brain region, it is crucial in maintaining balance. Located in the inner ear, it is a network of tubes filled with a liquid called endolymph. Movement in the head causes the liquid to move which is sensed by hair like vestibular cells. The vestibular system, acting as an inertial sensor for the brain, produces signals about our balance and head position, which are transmitted via the vestibular nerve to maintain balance.

When we leave a merry-go-round, the liquid in our vestibular system is still moving which gives the signal to the brain that we are still moving around while our visual perception tells us that we are stationary. This confuses our brains and makes us feel dizzy. To remedy this, all we need to do is keep focusing on a single point (like a tree) when on the merry-go-round by moving our head, this will prevent excessive movement of the fluid in the vestibular system and prevent dizziness

In the upcoming blogs of this series, we’ll dive further into the anatomy, the development, and the different functions of our brains.


Author: Siddharth Chaturvedi
Buddy: Helena Olraun
Editor: Viola Hollestein
Translator: Marlijn ter Bekke
Editor translation: Lucas Geelen
image by Guillermo Diaz via unsplash

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