Mesencephalon or midbrain: what it is, parts and functions

The brain is one of the most complex organs in our body and the one that makes sure that all the rest work properly. Despite this, it is also one of the most unknown by the majority of the population. There are many structures that make it up and the neural pathways that pass through it, and there are also many implications that this has in our day to day life.

The mesencephalon or midbrain, for example, is one of these structures that compose it, but if I gave you a brain map, would you know how to locate it? Well, it depends on the map that has given you this would be impossible because, you can't see it! Did you know this information? If you want to learn this and other things about the mesencephalon: what it is, parts and functions, as well as why it is so important and its location. Keep reading! In this Psychology-Online article we explain it to you.

Index

1. What is the midbrain
2. midbrain location
3. Importance of the midbrain
4. Parts of the midbrain
5. midbrain functions

The midbrain or, also known as the midbrain, is a brain structure very important since it participates in some of the actions controlled by the central nervous system. Which leads us to ensure that an alteration in it will lead to a considerable deterioration in the quality of life of people.

The midbrain is located in the most rostral part of the brainstem and it is very difficult to see with the naked eye when we look at a complete brain, since it is hidden by the cerebral cortex.

Below we list the reasons why the midbrain is considered to be of paramount importance in Regarding the functions that it develops in our organism and, therefore, the main characteristics of the midbrain:

• The red nucleus and black substance, found in the midbrain, are both important components of the motor system. A bundle of axons arising from the red nucleus constitutes one of the two main fiber systems that transmit informationmotorboat from the cerebral cortex and cerebellum to the spinal cord.
• In addition, the substantia nigra contains neurons whose axons project to the caudate nucleus and the putamen, components of the basal nuclei. The degeneration of these neurons causes Parkinson's disease.
• As a curiosity, also in the mesencephalon includes Lewy bodiesAlthough they have a diffuse distribution throughout the cortex, they appear to be found in greater numbers here along with other subcortical structures. Causing, in case of accumulation of these, Lewy body dementia, which normally begins after having suffered from an acute confusional syndrome or after the appearance of serious perceptual alterations such as hallucinations visuals.

Different distinctions can be made when studying the components of the mesencephalon or midbrain. First we will do it according to its two faces (the ventral and the dorsal) and then according to its different components:

• ventral sideof the midbrain: we find the cerebral peduncles, formed by a set of axons that conduct motor information, we distinguish them because they look like two slightly inclined columns.
• Dorsal aspect of the midbrain: we find the ventral tegmental area (with the origin of the mesocorticolimbic pathway, formed by neurons dopaminergic neurons), the substantia nigra (originating in the nigrostriatal pathway and also formed by dopaminergic neurons), the quadrigeminal colliculi and tubercles, or the tegmentum.

Although mainly, we could divide the parts of the midbrain or the midbrain into:

1. tectum. Located dorsal to the midbrain and formed by bumps on the dorsal surface of the brainstem:

• Superior quadrigeminal tubercles, which are a part of the visual system.
• Inferior quadrigeminal tubercles, which belong to the auditory system.

2. Tegmentum. It is composed of the portion of the midbrain located below the tectum. Understands:

• The rostral end of the reticular formation. It receives sensory information through various pathways, and projects axons to: the cerebral cortex, the thalamus, and the spinal cord.
• the cores that control eye movements.
• periaquaductal gray matter. Mesencephalic region that surrounds the cerebral aqueduct and contains neuronal circuits involved in behaviors typical of the species.
• The ventral tegmental area.
• the black substance. Dark-colored region of the tegmentum whose neurons communicate with the caudate nucleus and the putamen in the basal ganglia.

3. red core. Large mesencephalic nucleus that receives input from the cerebellum and the motor cortex and sends axons to motor neurons in the spinal cord.

The general function of the brainstem is to collect and send both sensory and motor information from head and face, unlike the spinal cord which transmits and receives information from the trunk and extremities. Therefore, we could say that brainstem functions are:

• Collects and sends sensory information from the head and face.
• Receives information from the brain and distributes motor and vegetative information from the head and face to the periphery.
• Organizes head and face reflex responses.
• In addition, it has a special function, which is the control of cortical activation, related to the nuclei of the reticular formation.

Some specific vegetative functions are related to controlling the acceptance or rejection of sweet or bitter foods, and can even be modulated by satiety or by physiological signals of hunger, such as decreased glucose metabolism, or food in the digestive tract.

Specific, midbrain functions or midbrain would be the following:

• The reticular formation, in its passage through the midbrain, participates in sleep and arousal (or activation), attention, muscle tone, movement, and various vital reflexes.
• Interoceptive representation of emotions and homeostatic regulation.
• The quadrigeminal tubercles are involved, in mammals, in the visual reflexes and reactions to moving stimuli.
• Control of consecutive sequences of typical movements of the species.

If you liked this article about the Mesencephalon: what it is, parts and functions, we recommend you read this other post about the Brain stem: what it is, functions and parts for you to expand your knowledge.

This article is merely informative, in Psychology-Online we do not have the power to make a diagnosis or recommend a treatment. We invite you to go to a psychologist to treat your particular case.

If you want to read more articles similar to Mesencephalon: what it is, parts and functions, we recommend that you enter our category of neuropsychology.

• Carlson, N. R. (2014). physiology of behavior. Madrid. Pearson Education, S.A.
• Look, C., (2014). Segmentation of magnetic resonance images of the midbrain by means of an active shape model. doctoral thesis National Autonomous University of Mexico. Mexico D.C.
• Portell, I. (2015). Brainstem. Autonomous University of Barcelona.