Our nervous system is extremely complex and is recognized because it is composed of many main structures, with indispensable functions that involve the total functionality of our body. In this sense, the brain is one of these structures and tissues, explicitly an organ.
Thebrain, on the other hand, is composed or divided into three areas that are the forebrain, midbrain and rhombencephalon. The midbrain is also known as the midbrain and is responsible for controlling hearing, vision and movements of our body.
Next we will talk in greater depth about this area of the brain and its characteristics, what are its subdivisions and the main functions that it is responsible for processing.
What is the midbrain?
Themidbrainis defined by theNeuroWikaNeurology Content Portal as the most cephalic region of the brainstem. It has an approximate length of 2.5 cm and has no defined upper limit.
Inside the midbrain are two nuclei, which are related to automatic movements and although their functionality seems not to have been defined yet, in their entirety it is responsible for involuntary motor skills, reflexes and automation of the body.
Characteristics of the midbrain
Between its organization and functionality, the midbrain meets certain characteristics that we will develop next, and thus we will understand with them more precisely, what this middle brain implies in our central nervous system.
It is an essential part of the nervous system
The activity that this area of the brain fulfills in our system, is reflected and related in the mechanisms of adjustment and involuntary reflexes in our body such as the ocular or those that our own organism demands of us in certain periods of time, such as those of posture in the spine.
Similarly, the midbrain influences our balance and it is consistent to say that it participates by receiving vestibular, spinal and cortex and brain stem afferents.
In addition to this, in the midbrain there are elements such as the black substance, the gray substance, the Silvio aqueduct and others.
It is located in the middle of the brain
As we previously mentioned, it is located in the middle of the brain. It extends from the diencephalon to the pons and from an external view only its front face can be seen.
It is above the parts that comprise the rhombencephalon and shares with them the cranial cavity in the posterior and inferior zone.
It has the shape of a trapezoid
It could be described that way to have some reference. It is mentioned that it is similar to a trapezoid, but with a narrower base and Silvio’s hole through it.
Links various parts of the brain
The midbrain transmits sensory signals and is responsible for connecting the brain stem with various structures in the hindbrain and forebrain, including the cerebellum and diencephalon .
Through it flows the cerebrospinal fluid
The midbrain is traversed by the cerebral aqueduct, which connects the third and fourth ventricle, as part of what is considered the cerebrospinal fluid transport circuit in our body.
Precisely, it is Silvio’s hole, which is the small channel that crosses the midbrain and through which it flows.
Its malfunction triggers various pathologies
Lesions in the midbrain can lead to the development of different types of pathologies in our body.
In a Science and Medicine Blog they developed an article about Parkinson ‘s , where they explain that it is produced as a consequence of the destruction of a portion of the substantia nigra.
On the other hand, syndromes that affect the ocular nerves are also caused by failures that occur in this part of the brain, especially when heart attacks occur in this area. Other types of vascular syndromes can be developed and affect the quality of life of the individual with little chance of recovery.
Parts of the midbrain
The midbrain has an anatomy in which different components in its structure can be differentiated and recognized. They will be described below, to understand certain connections and functionalities.
The roof
It is a structure made up of colliculi: two superior and two inferior. The superior ones are in charge of controlling the movements of the ocular muscle and the inferior ones produce motor reactions to auditory stimuli.
The Tectumis also known as the quadrigeminal plate and constitutes the posterior face of the midbrain. There is also a frenulum that crosses the division of the colliculi and between the two superior colliculi there is an area where thePineal Gland rests .
roof
It is the base of the midbrain and is in charge of controlling the attention and consciousness of our body. This is where the black substance is located.
The tegmental area is recognized for being where the mesocortical and mesolimbic dopaminergic systems also originate and it has also been recognized that excessive activity in the cells of this area of the brain influences the positive symptoms of schizophrenia.
Upper Colliculus
As we mentioned later, the superior colliculi are responsible for the performance of the movements of the ocular nerves. They are layered structures and centers of sensory integration.
Inferior colliculus
The inferior colliculus constitutes a homogeneous mass of gray matter, which protrudes the posterior surface of the midbrain. It is the processing site of major auditory functions and is directed to the body through the lower conjunctival arm.
Black substance
At the School of Medicine of the Catholic University of Chile , in a research paper on the Midbrain , they explain that the substantia nigra is a motor nucleus located along the midbrain.
It is made up of a pars compacta (input to the basal ganglia circuit), which contains a large number of melanin granules, and a pars recticularis (output that transmits signals from the basal ganglia to other brain structures), which does not have melanin but does contain an iron-rich compound that gives it a red color.
functions of the midbrain
All the previously mentioned important elements and characteristics lead us to the functionality of the midbrain. It is a complex area with unconditioned reflexes, which develop many of our responses and movements that we have the capacity to produce.
Receive sensory information
Sensory information is received in the midbrain, especially from the visual and auditory fields, allowing it to be modulated and sent or processed against the reflexes that are capable of controlling in this area of the brain.
Regulate muscle movement
Regulation of posture, muscle adjustment, motor patterns, and balance are various motor functions, which are mainly related to the mesencephalic red nucleus, due to the system it controls from the spinal motor system.
It also facilitates the change of position of these in postural reflex movements.
Effect visual responses and eye movement
Among the reflexes that are described in the research work at the School of Medicine of the Catholic University of Chile, the visuo-ocular (visual fixation reflex) and the vestibulo-oculo-cephalic-gyrus (to follow the reflexes) are described. objects in the visual field).
Also mentioned are the pupillary reflections of light and accommodation (adaptation by sudden change of gaze).
Regulate hearing
It participates in the auditory pathway reacting to stimuli of this type, even from visual functionality, such as reacting to sounds and finding their origin with the gaze.
The processing of these responses is located in the inferior colliculi. In a work titledAnatomy and Physiology of the Auditory Pathway , they explain how these colliculi constitute a mandatory station for auditory information.
Control Laughter and Crying
At the pontine midbrain junction, there is a coordinating center where the functionality of the muscles involved in the process of laughter and crying (including facial expression, vocalization and breathing) is performed.
In this sense, in the investigation entitled Neurology of pathological laughter and crying they explain that in this pontine midbrain center the nuclei of the cranial nerves that innervate the muscles involved will be activated synchronously.
Regulate consciousness and sleep
In the investigation of the Faculty of Medicine of Navarra , Pamplona entitled ” Anatomical bases of sleep “ , it is explained that although it is in the hypothalamus where the control of the sleep and wake spindles is actually found, there are fibers of this nucleus that not only They project to the midbrain but also to areas such as the medulla oblongata, which during wakefulness and electrical stimulation of this site produces sleep
Keep the body in balance
The various functions that we have described throughout the article, which involve muscle control and these, are related to the balance of our body. It also controls movements and coordination through its nervous tissues, stimuli and reflexes.
Participate in the regulation of body temperature
The midbrain is also involved in homeostatic functions, which leads to produce, thanks to these, a regulation of body temperatures
University Professional in the area of Human Resources, Postgraduate in Occupational Health and Hygiene of the Work Environment, 14 years of experience in the area of health. Interested in topics of Psychology, Occupational Health, and General Medicine.