Wernicke's area: anatomy, functions and disorders

Although since the end of the 19th century the localizationist vision has predominated, which attributes the understanding of language to the Wernicke area, a region located in the lobe temporally, in recent years the scientific community is showing that the nervous complexity of this characteristically human function is much greater than believed.

In this article we will describe the anatomical structure and functions of Wernicke's area. We will also talk about the most distinctive symptoms of the linguistic disorder associated with lesions in this region of the brain: Wernicke's aphasia, also called "sensory" or "receptive".

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Anatomy and structure of Wernicke's area

Wernicke's area is a region of the brain that is located in the posterior part of the superior temporal gyrus of the dominant hemisphere, generally the left, with a large number of exceptions among left-handed people. The superior temporal gyrus is located near the primary auditory cortex, as well as the outermost parts of this sensory system.

This area of ​​the brain borders the angular gyrus of the parietal lobe, involved in language, reasoning and memory. The blood supply to the Wernicke region depends on the middle cerebral artery, which is essential for the transport of nutrients to the cortex as a whole.

There is some disagreement about the exact delimitation of the Wernicke area. Thus, while many experts consider that it identifies with the anterior part of Brodmann's area 22 of the temporal lobe (involved in the recognition of auditory verbal stimuli according to neurofunctional studies), others place it in the multimodal parietal cortex.

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Functions of this brain region

This cortical structure was first described by the German neurologist and psychiatrist Carl Wernicke in the year 1874. This author proposed the existence of a link between the brain region that would be named after him and the production and imitation of oral language. His hypothesis was based on the analysis of lesions in the superior temporal gyrus and its associated signs.

From this milestone in the field of neuroanatomy, the vision began to consolidate localizationist who attributes receptive language (i.e., auditory understanding of speech) to Wernicke area. From this point of view the region is considered the brain center for language understanding, or at least a very relevant structure in this function.

Among the cognitive functions that were related to Wernicke's area throughout the 19th and 20th centuries we find the semantic processing of linguistic information (both in auditory and written formats), recognition of language and its interpretation.

Recent research on language

It's important to mention the relationship between Wernicke's area and Broca's area, located in the forebrain and traditionally associated with the production of language. The two regions have long been believed to be connected by a bundle of nerve fibers called the "arcuate bundle."

However, we now know that the arcuate fasciculus actually connects Wernicke's area with the premotor and motor cortex in general, and not just with the Broca's area; in any case, the uncinate issue would be responsible for said interaction. Even more relevant are the discoveries about the functions of these two regions.

Although understanding of language has traditionally been attributed to Wernicke's area, recent neuroimaging studies suggest that this region it could be more involved in the production of speech. Paradoxically, today it is also believed that Broca's area can be related mainly to the understanding of language and not to its production.

In any case, it is important to note that brain functions are not usually located in a single brain structure. In the same way, language is a very complex function in which large regions and networks that involve mainly, but not exclusively, the frontal and lobes play important roles. temporary.

Symptoms of Wernicke's aphasia

Lesions in the temporal lobe of the dominant hemisphere of the brain often cause a language disorder called "Wernicke's aphasia" because of its relationship with the area that occupies us. This alteration has also been called "sensory aphasia", "receptive", "understanding" and "fluent" based on its defining characteristics.

People with Wernicke's aphasia have trouble understanding other people's speech. In addition, and despite being fluid and well articulated, his speech is often meaningless and full of paraphasias, or substitutions of phonemes for similar ones. These alterations also occur in written language, which shares a brain base with spoken language.

The similarity of the symptoms of Wernicke's aphasia with the language alterations that occur in the context of schizophrenia is striking. Thus, in both disorders we find phenomena such as neologisms (words without shared meaning) and the lack of coherence of the sentences (schizoafasia, paragrammatism, or word salad).

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