Inferior temporal gyrus: characteristics and functions

A summary description of the characteristics and functions of the inferior temporal gyrus of the brain.

The inferior temporal gyrus is a brain structure located in the inferior part of the temporal lobe and an area that we know is responsible for visual perception and discrimination, as well as other functions that have been investigated subsequently, such as arithmetic and number processing.

In this article we explain what is the inferior temporal gyrus, what is its structure and location, what is its function and what is its function.In this article we explain what the inferior temporal gyrus is, what its structure and location are, what functions it performs in the brain and what are the main disorders associated with damage to this brain structure.

Inferior temporal gyrus: definition, structure and location.

The inferior temporal gyrus is a gyrus of the brain located, as its name suggests, in the lower part of the temporal lobe.. This lobe consists of three gyri on its lateral surface: the superior, the medial and the inferior, which we will discuss throughout the article.

The convolutions or gyri are the folds that give that wrinkled appearance to the cerebral cortex, the most developed area of the brain and the one in charge of higher cognitive functions such as thinking, language, planning or decision making.

The inferior temporal gyrus is, as we mentioned, one of the three convolutions of the temporal lobe, one of the 6 main lobes of each cerebral hemisphere and whose main functions involve the management of auditory language, participation in speech comprehension systems, visual object recognition or face identification, among others.

The inferior temporal gyrus is located at the lower lateral border of each cerebral hemisphere, below the medial temporal gyrus and posterior to the inferior occipital gyrus.. It extends around the inferolateral border to the inner surface of the temporal lobe, where it is bounded by the inferior sulcus.

It should also be noted that the main source of Blood supply to this brain area comes from the four temporal branches of the middle cerebral artery that emerge from the lateral sulcus or Sylvian fissure, a cleft that crosses transversely the entire brain from its base and on both sides.

Functions

The inferior temporal gyrus is a brain gyrus involved in visual object recognition and visual image processing.The inferior temporal gyrus, due to its connection with areas of the inferior occipital gyrus that form the occipital lobe, the main brain structure related to visual perception and the interpretation and recognition of images, as well as spatial recognition or discrimination of movements and colors.

The inferior temporal gyrus also appears to specialize in the interpretation and processing of numbers.. A study in Palo Alto (USA) showed that the inferior temporal area was significantly and differentially activated when participants were presented with different numbers and their digits (e.g. "45" or "9"), but not with letters ("forty-five" or "nine") or homophonous words (e.g. "one" instead of "1").

Although it was already known that this area of the brain was involved in the processing of visual information, this and other investigations led to the conclusion that this region was also involved in the arithmetic processing of numbers.

On the other hand, another study carried out in Japan by means of functional magnetic resonance imaging showed that the left inferior temporal gyrus played an important role in logo writing. an important role in the writing of logograms (a system of characters or signs representing (a system of characters or signs that represent a meaning on their own, used in languages such as Chinese) and, by extension, in other non-alphabetic languages.

Disorders related to damage in this structure

Lesions in a brain structure such as the inferior temporal gyrus can lead to disorders such as visual agnosia, which involves an inability to identify the brain as a whole.which involves an inability to identify, recognize and interpret visual stimuli. When unilateral damage occurs, the functional specialization of the cerebral hemispheres becomes evident: only lesions on the right side affect higher visual functions. And why does this happen?

In most people, the left hemisphere is dominant with regard to language and the processing and interpretation of visual stimuli, while the right or non-dominant hemisphere is specialized for non-verbal material and information, such as the recognition of faces and emotional facial expressions. This is why only the higher visual functions are affected when there is damage to the right temporal area.

Another common disorder when a person suffers damage to the inferior temporal gyrus and adjacent structures is prosopagnosia or face blindness.The damage to the temporal lobe, which causes an inability to recognize and discriminate faces, can also lead to problems in recognizing objects or places.

Several studies have also concluded that damage to temporal lobe structures, specifically in the inferior and medial temporal area, can cause problems related to semantic memory, which is responsible for recognizing the meaning of objects, vocabulary or general knowledge. This is observed in semantic dementia, a neurodegenerative disease characterized by the gradual loss of this type of memory, both verbal and nonverbal.

Finally, it should be noted that some research has been able to conclude that lesions in the inferior temporal gyrus would result in an agraphia of the logographic writing systems.The ability to write correctly is affected in agraphia and usually occurs in conjunction with other language disorders such as aphasia and alexia. In agraphia, a person's ability to write correctly is affected and usually occurs in conjunction with other language disorders such as aphasia and alexia.

Bibliographical references:

Clark, D. L., Boutros, N. N., & Méndez, M. F. (2012). The brain and behavior: neuroanatomy for psychologists. Modern Handbook. Nobre, A. C., Allison, T., & McCarthy, G. (1994). Word recognition in the human inferior temporal lobe. Nature, 372(6503), 260-263. Snell, R. S. (2007). Clinical neuroanatomy. Ed. Médica Panamericana.