Supramarginal gyrus: associated functions and disorders

The human capacity to read and write involves a large number of complex mental processes in which visual and auditory information is joined, and later motor in the case of writing. They involve complex processing and integration, which take place in different regions of the brain.

One of the most important is Brodman's area 40, or supramarginal gyrus. Let's see what it is like and what functions this part of the brain is responsible for.

• Related article: "Parts of the human brain (and functions)"

Supramarginal gyrus: this is this part of the parietal lobe

The supramarginal gyrus is one of the gyri or convolutions of the brain, that is, one of the visible folds of the cerebral cortex. It is located in the inferior parietal lobe, just above the Silvio fissure and closely related to the angular gyrus and the Wernicke area. This gyrus is present bilaterally (that is, there is one in each hemisphere brain) and which is of great importance in allowing some complex processes to have place.

The parieta lobe

l is linked to a large number of basic functions in our day to day, such as language both orally and in writing or auditory perception and participates in aspects such as orientation and memory. The functions performed by the parietal lobe cortex are mainly related to sensory perception and the processing and integration of information obtained by the senses.

The latter is one of the functions of the business at hand. The angular gyrus is considered an association area, in which information from other brain regions is integrated.

• You may be interested: "Neocortex (brain): structure and functions"

Functions of the supramarginal gyrus

The supramarginal gyrus is a very important brain area, which, although it is essentially known for its role in language, has several functions.

1. Literacy

One of the best known functions of the supramarginal gyrus is to allow, together with the angular gyrus, literacy. In order to read and write we need to be able to carry out the integration of visual and sound material in such a way that we can associate phonemes and graphemes, that is, the sounds and the letters that represent them. It is both turns, the angular and the supramarginal, which also allow associating visual representation and meaning.

This function is what makes the supramarginal gyrus together with the Broca and Wernicke areas and the angular gyrus. one of the main brain structures of language.

2. Work memory

Regardless of its role in language, the supramarginal gyrus has been shown to have connections with the dorsolateral prefrontal cortex that make it a relevant area for updating the work memory.

3. Learning

It has also been observed that the supramarginal gyrus participates in the acquisition of skills, especially those that involve movement. Although it is not something confirmed, it is suspected that it is capable of record information regarding the position of the extremities based on the memory of previous events.

4. Tactile perception

The supramarginal gyrus has been linked not only to language and cognitive aspects but also to the perception of tactile stimuli, specifically their recognition.

Disorders and situations in which he is altered

The alteration or injury of this brain region can have different repercussions of severity variable, being visible alterations in the supramarginal gyrus in patients with different disorders.

1. Aphasia

It is common to find affectations or alterations in this area in patients with aphasia. It is understood as such disorder in which the understanding and / or expression of language is difficult or impossible, caused by a brain injury.

The type of aphasia in which supramarginal gyrus damage is most common is conduction, in which the word repetition is impaired even though language comprehension and expression remain unaltered.

• Related article: "Aphasias: the main language disorders"

2. Alexia

Because the supramarginal gyrus and is one of the main areas along with the angular of the integration between visual and auditory material, its injury or dysfunction and are linked to alexia, which implies the existence of severe difficulties when interpreting or reading a text.

In this way, a supramarginal gyrus injury will suppose a presumable impaired ability to read not being able to correctly associate visual representation with its meaning.

• You may be interested: "Alexia and agrafia: alterations in written language due to brain injury"

3. Bodily neglect

As we have said, the supramarginal gyrus is not only involved in language but also performs other functions. Likewise, alterations in the supramarginal gyrus can also cause the presence of spatial neglect at the level of the body itself. There may also be some problems when it comes to getting the working memory to work properly.

4. Schizophrenia

Apart from that, supramarginal gyrus alterations also appear in some mental disorders. For example, it is observed that there is a relationship between this area and auditory hallucinations in schizophrenia, with a correlation between the size of the supramarginal gyrus and their severity.

• You may be interested: "The 6 types of schizophrenia and associated characteristics"

Bibliographic references:

• Clark, D.L.; Boutros, N.N. and Méndez, M.F. (2012). The brain and behavior: neuroanatomy for psychologists. 2nd edition. The Modern Manual. Mexico.