Although since the end of the 19th century the localizationist view has predominated that attributes language comprehension to the Wernicke area, a region located in the temporal lobe, in recent years the scientific community is demonstrating that the nervous complexity of this characteristically human function is much greater than previously thought.

In this article we will describe the anatomical structure and functions of the Wernicke area . We will also discuss 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”.

Anatomy and structure of the Wernicke area

The Wernicke area is a region of the brain that is located at the back of the upper temporal gyrus of the dominant hemisphere , usually the left one, with a large number of exceptions among left-handed people. The upper 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 on the angular rotation of the parietal lobe, which is 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 is identified 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 cortex of the parietal.

Functions of this brain region

This cortical structure was described for the first time by the German neurologist and psychiatrist Carl Wernicke in the year 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 upper temporal gyrus and their associated signs.

From this milestone in the field of neuroanatomy, the localizationist view that attributes receptive language (i.e., auditory speech understanding) to the Wernicke area began to be consolidated. From this point of view the region is considered the brain centre 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 were the semantic processing of linguistic information (both in auditory and written format), language recognition and its interpretation.

Recent research on language

It is important to mention the relationship between Wernicke’s area and Broca’s area , located in the prosencephalon and traditionally associated with the production of language. It has long been believed that the two regions are connected by a set of nerve fibres known as the “arched fascicle”.

However, at present we know that in reality the arched fascicle connects the Wernicke area with the premotor and motor cortex in general, and not only with the Broca area; in any case it would be the uncinado fascicle that is responsible for this interaction. Even more relevant are the discoveries about the functions of these two regions.

While language comprehension has traditionally been attributed to the Wernicke area, recent neuroimaging studies suggest that this region may rather be involved in speech production . Paradoxically, it is now also believed that Broca’s area may be mainly related 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. Similarly, language is a very complex function in which large regions and networks play important roles involving mainly, but not exclusively, the frontal and temporal lobes.

Symptoms of Wernicke’s Aphasia

Injuries to the temporal lobe of the dominant hemisphere of the brain often cause a language disorder that has been called “Wernicke’s Aphasia” because of its relationship to the area under consideration. This disorder has also been called “sensory aphasia”, “receptive”, “understanding” and “fluent” based on its defining characteristics.

People with Wernicke’s aphasia have difficulty understanding other people’s speech. In addition, and despite being fluent and well articulated, their speech is often meaningless and full of paraphrases , 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 disorders that occur in the context of schizophrenia is striking. Thus, in both disorders we find phenomena such as neologisms (words without a shared meaning) and the lack of coherence in sentences (schizoaffia, paragrammatism or word salad) .