Precentral Gyrus: Characteristics And Functions Of This Part Of The Brain
If we look at a photograph of a human brain, the first thing we probably see is the outermost layer, a wrinkled, grayish mass. This most external and superficial part is the cerebral cortex, and the aforementioned folds are its convolutions or gyri and its sulci.
These folds emerge little by little during the brain development of the fetus, participating in the neuronal matter from which they are formed in different brain functions of great importance for our daily lives. One of them that is easily identifiable is the precentral gyrus which we are going to talk about throughout this article.
The precentral gyrus: description and neuroanatomical location
The precentral gyrus is one of the various cerebral gyri or gyri present in the cerebral cortex, being the part that at an observational level protrudes outward from said folds. This turn It is part of the primary motor area so its connection with the ability to generate movement is relevant.
This brain region can be located in the frontal lobe, just in front of Rolando’s fissure or central sulcus that separates frontal from parietal. For this reason, another name for the precentral gyrus is the prerolandic gyrus or gyrus.
The precentral gyrus is present in both hemispheres, adjoining the Silvian fissure at the bottom. Just after the fissure we would find the postcentral gyrus, while more rostrally we would find the precentral fissure or sulcus.
Functionally speaking, it would be deeply communicated with the secondary motor cortex and the supplementary motor cortex, which allow planning and programming movement, and Broca’s area, which allows programming movements linked to language. Furthermore also has connections with other brain areas such as the cingulate or hypothalamus
In the precentral gyrus and part of the central or Roland sulcus we can see Penfield’s homunculus represented, both areas being essential for carrying out voluntary movement. Specifically, it is considered that the lower areas of the precentral gyrus control or innervate the regions of the head and face, while the upper parts would be in charge of innervating the legs.
Another aspect to highlight about this gyrus is that in it we can find some of the largest pyramidal cells in the entire body, the Betz cells, their axons reaching the spinal cord.
Associated functions
The precentral gyrus is a region of the brain with great importance when it comes to enable normative functionality and human behavior, being involved in various functions. Among them we highlight the following.
1. Voluntary movement
It is considered that in the precentral gyrus, identified with the primary motor cortex, there is the motor representation and the first connections responsible for allowing the movement of different body regions. This brain region is largely due to impulse and ability to move both simple and complex.
2. Travel capacity
The ability to move or simply interacting with the environment physically It is, due to the need for movement to be performed, one of the different functions in which there is a participation of the precentral gyrus.
Our ability to communicate with others depends largely on the possibility of moving our voluntary muscles, which depends largely on the action of the motor cortex of which the precentral gyrus is a part in order to be able to speak (something which requires, among other things, the movement of lips and tongue) or communicate using gestures (muscles of the face and extremities).
4. Response to stimulation
Although the somatosensory system corresponds more to the postcentral gyrus, the truth is that during experiments with monkeys it has been observed that in the precentral gyrus we can also find regions responsible for providing a motor response to stimulation, specifically in order to seek protection or defense against possible threats This effect has been observed with unfamiliar stimuli, with the brain response being smaller or non-existent when faced with stimuli to which one is already accustomed.
Problems generated by your injury
The presence of injuries in the precentral gyrus can generate, as can be imagined based on the importance of its functions, serious repercussions on the life of those who suffer from them. An example of this is the presence of paralysis in the form of monoplegia, hemiplegia, paraplegia or tetraplegia potentially losing the ability to move different parts of the body.
It has also been observed that it has an influence on praxias or the performance of complex movements, with injury to this gyrus causing the appearance of apraxias. Likewise, damage to the precentral gyrus has also been associated with the presence of Broca’s aphasia, making it impossible or complicating the production of the movements necessary to express oneself fluently.
