Angular gyrus (brain): areas and functions

The ability of the person to understand what he hears or reads, is something that is done in a so automatic, that we rarely stop to think thanks to what structures of the brain this is possible.

These among many other functions are typical of the angular gyrus of the brain. Throughout this article we will talk about what it is, where it is located, what its functions are and what happens when it does not work correctly.

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

What is the angular turn?

Brain twists refer to those mounds formed in the brain, caused by the folds of the cerebral cortex. One of them is the angular gyrus, this gyrus is located in the posterior area of ​​one of the cerebral convolutions; specifically in that located between the intraparietal sulcus and the horizontal ramification of Silvio's fissure.

Also, the angular turn corresponds to Brodmann's area 39, which together with area 22 and 40, form Wernicke's area. This region of the temporal lobe is the so-called auditory associative cortex and its main function is to enable people to understand words and have the ability to produce speeches with meaning.

An injury to this Wernicke area can cause both blindness and verbal deafness. Verbal blindness, or alexia, is the inability to understand written words; while verbal deafness, or verbal auditory agnosia, consists of the inability to understand the words heard.

Finally, angular gyrus is associated with both the interpretation of language and mathematics or cognition, integrating information from other areas of the brain. Next, we will see what implications the angular gyrus has on the different brain functions.

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What functions does it perform?

As mentioned above, the angular gyrus takes care of aspects related to language production, with the skills for calculation and mathematics, with the visuospatial capacity and with some aspects cognitive These are functions acquired through experience, but which are supported by the biological predispositions that the human brain has when it comes to learning. That is, without proper stimulation, this part of the brain will not develop well.

Next, we break down all those functions that the angular gyrus performs in the brain these functions presented below.

1. Language

Given its implication in the Wernicke area functions, the angular gyrus has a critical role in producing meaningful sentences and phrases.

Likewise, it is one of the areas in charge of written verbal comprehension. That is, thanks to him, people can understand what we read.

2. Calculation

Regarding the functions related to calculus and mathematics, angular rotation intervenes in the person's ability to perform mathematical operations necessary to obtain a result, a value or to solve any type of mathematical problem.

On the other hand, he is also involved in learning arithmetic or basic mathematical operations and in the interpretation of numerical quantities and dimensions.

3. Visual

The angular gyrus intervenes in the spatial focus of attention, that is, in the orientation and spatial search of visual stimuli.

What's more, he is also in charge of visuospatial processing. Thanks to visuospatial processing, people can identify where objects are located in space, as well as the distance between them or between us and them.

4. Other functions

Finally, there are a multitude of functions in which the angular rotation has a more or less significant role.

These functions include:

• Involvement in creative verbal tasks.
• Executive behavior control.
• Processing of sequences of actions.
• Reading and coding symbols.
• Involvement in Theory of mind.

The Theory of Mind is a term that refers to the ability of the person to perceive and identify the thoughts and purposes of third parties and assign them to the possible person who emit.

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What if you are injured: Gerstmann syndrome

If due to an injury or a neurodegenerative process, the angular gyrus suffers some kind of damage, the anterior functions can be seriously affected.

Likewise, there is a specific syndrome associated with an injury or deterioration of this area known as Gerstmann syndrome.

This neurological disorder has been associated with damage or defective activity of the angular gyrus. It is characterized by presenting very little incidence in the population and by manifesting itself through a set of symptoms related to sensation, perception and the coding of information from the different senses.

• Related article: "Gerstmann syndrome: causes, symptoms and treatment"

Gerstmann syndrome symptoms

Among the most representative symptoms of this condition we find the following.

1. Digital agnosia

This is one of the main symptoms of Gerstmann syndrome. This type of agnosia is distinguished by causing the person to be unable to distinguish or identify the fingers of the hand, both their own and those of others.

This agnosia is not associated with any type of frailty. or lack of tactile perception of the fingers. The person is simply unable to name, choose, identify or orient their own fingers.

2. Acalculia

Acalculia consists of the appearance of difficulties related to mathematical and arithmetic skills. Within this symptom, the person can manifest different types of deficits:

• Inability to perform mathematical operations both written and mental.
• Problems interpreting mathematical signs.
• Problems maintaining or continuing orders or numerical series.
• Inability to design sequences.
• Difficulties in using numbers correctly.

3. Agrafia

When it comes to written language, people with Gerstmann syndrome suffer from a deficit in writing ability and capacity. Also known as agrafia.

These patients show problems in the transcription of words heard, in spontaneous writing and copying.

Also, other symptoms of agraphia are:

• Alteration in the ability to draw letters correctly.
• Lack of symmetry of the letters.
• Changes in the orientation of lines in writing.
• Use of various fonts.
• Invention of own characters.

4. Spatial disorientation

Patients with angular gyrus injuries They can also present problems in the distinction of the left and the right. So apparently, there is a deficit in the lateral orientation of the body itself in space.

In addition, these patients present great problems when it comes to identifying the left or right plane of any object, place, spatial situation or even the parts of the body itself.

Bibliographic references:

• Hirnstein, M.; Bayer, U.; Ellison, A.; Hausmann, M. (2011). TMS over the left angular gyrus impairs the ability to discriminate left from right. Neuropsychology. 49 (1): pp. 29 - 33.
• Lee, H; Devlin, J.T.; Shakeshaft, C.; Stewart, L.H.; Brennan, A.; Glensman, J.; Pitcher, K.; Crinion, J.; Mechelli, A.; Frackowiak, R.S.; Green, D.W.; Price, C.J. (2007). Anatomical traces of vocabulary acquisition in the adolescent brain. J Neurosci. 27 (5): pp. 1184 - 1189.
• Vatansever, D.; Manktelow, A. AND.; Sahakian, B.J.; Menon, D. K.; Stamatakis, E.A. (2017). Angular default mode network connectivity across working memory load. Human Brain Mapping. 38 (1): pp. 41 - 52.
• Rushworth, M.F.; Behrens, T.E.; Johansen-Berg, H. (2006). Connection patterns distinguish 3 regions of human parietal cortex. Cereb Cortex. 16 (10): pp. 1418 - 1430.