Although since the end of the 19th century the localizationist view that attributes language comprehension to Wernicke’s area, a region located in the temporal lobe, has predominated, in recent years the scientific community is demonstrating that the nervous complexity of this characteristically human function is much greater. greater than previously 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.”
Wernicke’s area is a region of the brain that It 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. Blood supply to Wernicke’s 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 over the exact delimitation of Wernicke’s area. Thus, while many experts consider that it is identified with the anterior part of Brodmann 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.
This cortical structure was First described by the German neurologist and psychiatrist Carl Wernicke in 1874. This author proposed the existence of a link between the brain region to which his name would be given 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 localizationist vision that attributes receptive language (that is, auditory understanding of speech) to Wernicke’s area began to consolidate. 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 format), the 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 language production. It has long been believed that the two regions are connected through a set of nerve fibers called the “arcuate fasciculus.”
However, we now know that the arcuate fasciculus actually connects Wernicke’s area with the premotor and motor cortex in general, and not only with Broca’s area; In any case, the uncinate fasciculus would be responsible for this interaction. Even more relevant are the discoveries regarding the functions of these two regions.
Although language comprehension has traditionally been attributed to Wernicke’s area, recent neuroimaging studies suggest that this region could be involved rather in speech production Paradoxically, today it is also believed that Broca’s area may be related mainly to the understanding of language and not its production.
In any case, it is important to highlight that brain functions are not usually located in a single brain structure. Likewise, language is a very complex function in which large regions and networks that mainly involve, but not exclusively, the frontal and temporal lobes play important roles.
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 in question. This alteration has also been called “sensory,” “receptive,” “comprehension,” and “fluid” aphasia based on its defining characteristics.
People with Wernicke’s aphasia have difficulty understanding other people’s speech. Furthermore, and despite being fluid and well articulated, his speech is usually meaningless and full of paraphasias, or substitutions of phonemes with 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 to the language disorders 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 sentences. (schizoaphasia, paragrammatism or word salad)
