The motor cortex: characteristics and functions

The motor cortex consists of three areas of the frontal lobe, which when stimulated make various parts of our body move.

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 in our daily lives. It is a part of our brain that helps us control, execute and plan movement.

Besides, 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 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 function properly. Let’s explore the motor cortex, also called the motor cortex.

What is the motor cortex and where is it located?

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. So, through it we generate, maintain and finalize the movements.

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

Howeverthis region consists of a representation called Penfield’s homunculus, This is an area that indicates the parts of the cortex where 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.

What regions is the motor cortex divided into?

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

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Primary motor cortex. It is the main area that is responsible for generating the nervous 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. This is a region with a low excitation threshold.motor area supplementary. 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 arousal threshold. 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 the Sylvian fissure. It is also related to the movements required for speech.Broca’s language motor area. This is an area that allows the production of spoken language. Therefore, the necessary muscle movements. It is located in the opercular and triangular portions of the inferior frontal gyrus.Posterior parietal cortex area. It consists of a region that transforms visual and other sensory information into motor information. This 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.

Pathology of the motor cortex

An injury to this part of the brain can have serious consequences. This is because it is necessary for most of the actions we perform on a daily basis. Some problems related to this crust are:

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Paralysis. It consists of the total or partial loss of movement of one or more parts of the body. When the injury occurs in one hemisphere it will occur on the contralateral side, for example when the motor cortex of the left hemisphere is injured, the affected side will be the right.Apraxias. The person is not able to carry out movements when requested. Then, the person understands the order they are given and has the willingness to carry it out, but lacks control of motor execution.Dysarthrias. It is a speech alteration. The person has difficulty articulating sounds or words.Agraphia. It consists of the lack of ability to express ideas and thoughts through written language.Broca’s aphasia. In this case the person suffers from an expressive language alteration. The signs are related to speech production. Thus, it is characterized by difficulty articulating or gesturing words, alterations in writing and problems remembering words.

However, research on the motor cortex is constant, Because through it we aim to find answers that help determine how to repair it after an injury. For the one button sample, Bunkerot and collaborators published research in 2018 in the Restorative Neurology and Neuroscience Magazine that favors this search.

In this group’s article the importance of the motor cortex for movement is evident. In their research they show the adaptive plasticity of the motor cortex after grasp reconstruction in individuals with tetraplegia. So, the surgical methodology they present is a window to cortical neuroplasticity, after recovery of arm and hand function.

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These neuroscience approaches help us understand how the cortex responds to injuries and treatment. This is the beginning of a path to find definitive solutions for cortical damage. That is its importance.

However, The motor cortex is the axis of our movement. Without it, we would not be able to carry out the actions we usually do. Through its encodings and connections it sends and receives signals to and from various parts of our body. Thus, it provides conscious voluntary movements and, therefore, we can relate to the world on a motor level.