Part of the brain that controls muscle movement

Thanks to our brain we can plan, eat, run and even smile. It is through the complex but fascinating functions of the cerebral motor cortex that we carry out various actions on a daily basis. It is a part of our brain that helps us control, execute, and plan movement.

In addition, it allows us to react to stimuli, which is essential for our survival. But this part of our brain does not act alone. These movements can happen thanks to the various connections and association with other areas of our body.

Through the article we will talk about the Part of the brain that controls muscle movement, we will see: what is its location and what are its structures and functions. In addition to associated pathologies when there is an injury or when it does not work properly. Let’s explore the motor cortex, also called the motor cortex.

Part of the brain that controls muscle movement

The part of the brain that controls movement is the motor cortex and the cerebellum.

The motor cortex is one of the parts of the telencephalon, which in turn is part of the brain. Its main function is to promote movement. Then, through it, we generate, maintain and finalize the movements.

Thanks to the motor cortex, voluntary movements are made consciously. This region of the brain is located in the frontal lobe, just in front of the Rolando fissure and the somatosensory region.

Now, this region consists of a representation called Penfield’s homunculus, it is an area that indicates the parts of the cortex where the movement occurs, within which there are some that stand out due to their large size. For example, the hands (especially the thumb), the tongue and the face.

In what regions is the motor cortex divided?

The motor cortex integrates various areas, through which movement is possible. Let’s look at them:

  • Primary motor cortex. It is the main area that is responsible for generating the nerve impulses that are needed for the production of voluntary movement. In addition, it is responsible for sending orders to the voluntary muscles of the body. In this way, they contract or tighten. It is a region with a low excitation threshold.
  • Supplementary motor area. It consists of an area that coordinates the movements of the postures. Thus, the sequence of movements in large muscle groups collaborates.
  • Premotor areas. They are areas with a high threshold of excitation. In addition, it is responsible for storing movements that come from past experiences.

Thus, it coordinates and at the same time programs the sequence of movements and the activity of the primary motor cortex. It is located in front of the primary motor cortex and close to Sylvian fissure. It is also related to the movements required for speech.

  • Broca’s language motor area. It is an area that allows the production of spoken language. Hence, the necessary muscle movements. It is found in the opercular and triangular portions of the inferior frontal gyrus.
  • Posterior parietal cortex area. It consists of a region that transforms visual information and more senses into motor. It is a region that sometimes appears within the motor classification because it has to do with movement, although on other occasions it appears as sensory due to its relationship with the senses.

Related problems and disorders

As we have indicated previously, the motor cortex is a very important brain region when it comes to being able to carry out practically any action. That is why an injury to these brain areas can have severe repercussions on the lives of patients.

One of the problems that the injury or destruction of the cortex or motor area can generate is paralysis and loss of mobility, whether in a specific part of the body, in a half body or in the whole body.

Hemiplegia or tetraplegia may appear. If the injury is only in one hemisphere, the paralysis will occur contralaterally: that is, if the right motor cortex is injured, the left hand will be paralyzed.

With regard to secondary motor areas, the effects of injury to them often alter the ability to perform movements in a coordinated and sequential manner. We are talking about the emergence of possible apraxias, or aphasias or dysarthria when we refer to problems in the production of the movements necessary to communicate.

Agrafia can also occur, as the movements necessary to write cannot be carried out correctly, eating problems or even visual problems due to the lack of proper regulation of the movement of the facial organs and muscles.

Cerebellar movement control

The cerebellum is much more than a kind of younger brother to the neocortex, nestled half-hidden between the occipital lobe and the brain stem. In fact, this curious structure resembling a flattened ball of wool is one of the most important parts of the brain.

Moreover, it is considered that in most cases the proper functioning of the cerebellum is essential for us to survive and the cases in which this rule is not met become news.

Although it is an apparently quite discrete structure because it is partly hidden by the cerebral cortex, the cerebellum is one of the areas of the brain with the highest density of neurons. In fact, about half of the neurons in the brain are located in this structure.

The functions of the cerebellum

The functioning of the cerebellum and the coordination of muscle activation have been related for years.

Thus, it was considered that the task of the cerebellum was, basically, to make it possible for us to maintain balance, for us to coordinate simple and complex movements and, in general, for the muscles of our body to respond faithfully and effectively to the orders issued by the brain.

For example, one of the main symptoms of changes in the cerebellum was considered to be loss of balance after drinking too much alcohol.

However, in recent years it has been discovered that the idea that the role of the cerebellum has to do with motor coordination is too simplistic. Thus, the cerebellum is not only involved in motor processes, but also plays an important role in many other functions.

The cerebellum and motor coordination

Old ideas about the role of the cerebellum as the focal point for muscle activation have not been disproved. 

Today it is still considered that this structure has a leading role in the coordination of movements, maintenance of balance and monitoring of neuronal signals aimed at activating muscles.

As the cerebellum is connected to many areas of the brain, it crosses the motor information elaborated in the higher regions of the brain with the more “concrete” and operational motor information aimed at activating muscle fibers, and checks that there are no inconsistencies between the two.

In addition, there is a debate generated around the possibility that one of the functions of the cerebellum is motor learning, that is, the ability to refine a pattern of movements so that it is perfected more and more.

The cerebellum has connections with different parts of the central nervous system, thanks to which it carries out multiple functions:

  • Vestibule-cerebellar. Sends corrective signals to the vestibular nuclei to modify posture and restore balance. Injury to this pathway can cause instability and nystagmus (small, rapid eye movements).
  • Hawthorn-cerebellar. It is involved in the control of posture and locomotion and modifies muscle tone. Control the movements of the limbs. An injury to this pathway would cause ataxic gait (staggering and swaying when walking).
  • Brain-cerebellar. Modulator of the descending systems of the cerebral cortex. It is key to the coordination of voluntary movements. It is involved in the initiation of movements. An injury to this connection would cause movements to take longer to start and finish.

In the different connections of the cerebellum with the other areas, it almost always acts as a regulator. It records information and regulates the movements of different parts of the body, depending on the structure to which it is connected. Functions such as maintaining balance or learning a movement could be difficult if these pathways are broken.

What happens when the cerebellum is damaged?

When the cerebellum is injured, some of its functions can be compromised and cause motor problems. There may be a loss of the ability to precisely control the direction, force, speed and amplitude of movements, as well as the ability to adapt output patterns to changing conditions.

The deficits can be produced suddenly by injury, or gradually by degeneration of the cerebellum. The cerebellar syndrome can be caused by injury to the cerebellum or the cerebellar pathways.

Organ damage can lead to two different symptomatic syndromes: vermian (archicerebellar) syndrome with alterations in static and gait, and cerebellar hemispheric (neocerebellar) syndrome with alterations in movement coordination.

The lesion of the afferent pathways produces an archicerebellar syndrome, and that of the efferent pathways is manifested by a neocerebellar syndrome.

A person with a cerebellar injury may find it difficult to maintain a seasonal posture (stand upright), and trying to do so leads to tremors.

It is also common to detect abnormalities in balance, gait, speech and even in the control of eye movements. So movements of all kinds can be affected. It is difficult for those who suffer from it to learn new motor sequences.

FAQS: Part of the brain that controls muscle movement

How does the brain tell muscles to move?

On orders from the brain, muscles move. The only way the brain binds to muscles is with single nerve cells in the spinal cord, or motor neurons. … A chemical is released at its culmination as the impulse passes down the axon to the muscle.

What part of the brain controls sequencing?

The frontal lobes: The executive functions are those that allow us to direct our behavior towards a goal and include attention, planning, sequencing and reorientation of our actions.

What part of the brain deals with involuntary movement?

The brain stem takes care of all the functions necessary for your body to be alive, such as breathing, digesting food, and circulating blood. Part of the brain stem’s job is to control the involuntary muscles – the ones that work automatically, without your thinking.

Which body part sends messages to the brain?

The thalamus is responsible for sending messages from sensory organs, such as the eyes, ears, nose, and fingers, to the cerebral cortex.

Does the brain send it messages to move?

Motor neurons send messages from the brain to the rest of the body.

Through the article we talked about the Part of the brain that controls muscle movement, we have seen what is its location and what are its structures and functions. In addition to associated pathologies when there is an injury or when it does not work properly. 

If you have any questions or comments please let us know!

References

Carlson, N. R. (2005). Foundations of physiological psychology. Pearson Education New Zealand.

Kandel, E. R., Schwartz, J. H., Jessell, T. M., Siegelbaum, S., Hudspeth, A. J., & Mack, S. (Eds.). (2000). Principles of neural science (Vol. 4, pp. 1227-1246). New York: McGraw-hill.

Kolb y I. Q. Whishaw, Fundamentals of Human Neuropsychology, New York 1996

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