Temporal lobe: structure and functions

The temporal lobe it is one of the most important structures of the cerebral cortex, and therefore also one of the most studied in neuroscience. One cannot understand the functioning of the central nervous system without knowing even a little what the temporal lobes are.

It not only covers a large part of the brain surface, but also it allows us to globally integrate a large part of the sensory information that reaches us through the environment, And plays a very important role in the processing of vision and hearing content, as well as language in general.

In this article, we will see what the characteristics of the temporal lobes are (because there are two of them in every brain), where they are located and what functions they perform.

Location of the temporal lobe

While the entire brain functions in a continuous interaction between different areas of the brain, studies from neuroscience show that many skills, abilities, capacities and functions of the nervous system are particularly linked to certain regions.

In this sense, the human cerebral cortex has traditionally been divided into five sections, called cerebral lobes. One of them is the temporal lobe, a fundamental brain region for skills as fundamental as speech or auditory perception, in addition to being closely linked to affectivity, memory and recognition.

The temporal lobe it is located on the underside of the brain, approximately at ear level. This region is anatomically separated from the parietal lobe, which corresponds to the superior lateral area, by the Silvio slit, and is in close contact with the occipital lobe. It is also the lobe with the greatest connection to the limbic system (with the orbital-frontal area), thus having a great influence on emotions and moods, as well as on memory.

Note that there are actually two temporal lobes, one in each cerebral hemisphere. This consideration is relevant, as some of the functions of this lobe are localized in most people to a specific hemisphere. However, when, due to neurological alterations, part of a temporal lobe stops functioning, these functions can be fulfilled in whole or in part by their counterpart in the opposite hemisphere.

On the other hand, the boundaries of the temporal lobe, like those of any other part of the brain, are very porous and to some extent diffuse. They do not correspond exactly to the physical limits of the areas of the nervous system in charge of certain tasksBut it’s a concept that helps position oneself when it comes to mapping the brain.

Most Relevant Brain Locations

In the temporal lobe there are a large number of structures. Indeed, in this area of ​​the cerebral cortex, many interconnections from different parts of the brain coincide, some of which are not too similar in terms of functions. In reality, the concept of the temporal lobe meets criteria that are much more anatomical than functional, so it is natural that there are groups of nerve cells and small organs that specialize in different tasks.

This causes the temporal lobe to incorporate groups of neurons responsible for performing many tasks, for example, integrating types of perceptual information from different senses. This is what makes it play an important role in language, the mental function in which they have to do with sounds, letters, etc.

Some of the most relevant parts of the temporal lobe are the following.

1. Auditory cortex

In the temporal lobe are the primary, secondary and associative auditory cortex. These areas of the brain are responsible, in addition to the perception of sounds, the encoding, decoding and interpretation of auditory information, being an essential element for survival and communication. In this last aspect it emphasizes its participation in the understanding of the speech, that takes place in the area of ​​Wernicke.

2. Wernicke region

In the secondary auditory zone of the dominant cerebral hemisphere, usually left behind for most of the population, Wernicke’s zone can be found. this zone she is the main person in charge of understanding the language, Allow verbal communication between individuals. However, tongue production occurs in another area known as the drilling area, located in the frontal cortex.

3. Angular rotation

This area is of particular importance, because it is the one that allows reading and writing. It combines visual information with auditory information, making it possible to attribute to each grapheme its corresponding phoneme and allowing a change in the type of data with which the brain works, from images to sounds with a symbolic component.

In people injured in this area, reading is usually affected, being very slow or non-existent.

4. Supramarginial circumference

It is part of the tertiary sensitive area. This twist participates in tactile recognition, in addition to participating in language. Thanks to it, we are able to recognize the relief of letters using our fingers and to associate them with sounds.

5.temporal medial

This area, which includes the hippocampus region and several relevant crusts, participates in memory and recognition, Process information and help move from short-term memory to long-term memory. The left hemisphere is responsible for verbal type information, while in the right visual models are stored.

It is in this area of ​​the temporal lobe that the first lesions appear in Alzheimer’s disease, producing its initial symptomatology.

6. Area of ​​parieto-temporo-occipital association

It is a space of association which is responsible for integrating visual, auditory and somatic perception. Among many other functions of great importance, its participation in perception and attention to space stands out, and suffering from heminegligence can cause its injury.

7. Zone of association of the limbic system

This part of the temporal lobe is responsible for providing emotional information to perceptions, Integrate emotion and perception. It also participates in memory and learning. In addition, other research has shown that it is also about regulating sexual behavior and maintaining emotional stability.

In the end, this part of the temporal lobe integrates mental processes linked to emotions and allows our experiences to leave an imprint on us that goes beyond what we can explain in words.

Disorders resulting from temporary injuries

All the areas that we have seen are of great importance for the proper functioning of the human body in general and the temporal lobes in particular.

however, it is not uncommon for accidents, illnesses and alterations to occur which can lead to malfunction of some of them. Let’s take a look at some typical storm disorders.

1. Cortical deafness

This disorder involves total loss of hearing, Although the sensory organs are functioning properly. In other words, auditory information reaches the perceptual organs, but is not processed by the brain, thus completely losing sound perception. This damage is caused by destruction of the primary and secondary auditory cortices, or the nerve pathways that access them, in both hemispheres.

2. Hemiacusis

As with deafness, this condition is caused by destruction of the primary and secondary auditory cortex, except that this destruction only took place in one hemisphere.

In this way, hearing in the ear opposite the hemisphere in which the injury occurred is completely lost, but since the auditory cortices of the other hemisphere remain functional, hearing is possible.

In addition, in some cases it is possible that over time a certain level of hearing is also gained by the ear which has become unusable because neural plasticity allows parts of the brain to learn functions that were previously performed by others, and it can happen. even when switching tasks from one hemisphere to another.

3. Prosopagnosi

With prosopagnosia, the affected person loses the ability to recognize faces, even those of their loved ones. Recognition of people must be given by other ways of brain processing.

This alteration is caused by a bilateral lesion of the temporocipital area..

4. Heminegligence

Caused by the affectation of the parieto-temporo-occipital association zone, this disorder involves difficulty in orienting, acting or responding to stimuli that occur on the side opposite to the injured hemisphere.. Attention to this perceptual hemicampus ceases, although the person himself may move so that the lost stimuli remain within the reach of the functional perceptual field. It usually appears with anosognosia, which is the ignorance of the existence of an alteration.

5. Aphasia

They are understood as aphasias speech disorders due to brain damage. The effects vary depending on the location of the lesion, and when it affects the temporal lobe, there are some characteristic symptoms.

Among the aphasias produced by storm injury, they highlight Wernicke’s aphasia (produced by an injury in the region of the same name, in which loss or difficulty in verbal comprehension and repetition takes place, something that cause of serious problems to those who suffer from it), anomic (loss or difficulty in finding the name of things, caused by injuries in the associative temporo-parieto-occipital areas) or sensory transcortical (in which there are difficulties in understanding but no repetition, being the product of lesions in the temporo-parieto-occipital associative zones).

If the connection of the Wernicke region with the Broca region, the arched fascicle, is injured, the so-called motor aphasia will occur, in which the difficulty of repetition and a slightly impaired comprehension stand out but a good one is maintained.

6. Anterograde amnesia

this disorder assumes the inability to store in the hardware memory new. In other words, it is impossible for the patient to recover (whether it is a permanent or temporary disability) the declarative information of the activity carried out after the injury.

This alteration is caused by injury to the medial temporal lobe, particularly in the hippocampus. Injuries in the left hemisphere will affect verbal information, while in the right the affectation will tend to be other pathways or non-verbal.

7. Klüver-Bucy syndrome

It is a very common disorder in dementias, such as Alzheimer’s disease. This assignment is characterized by the presence of gentleness, passivity, hyperoralism, difficulties with sustained attention, disappearance of fear and hypersexuality. It occurs in the face of lesions of the medial temporalis bilaterally.

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