He Wernicke area Is one of the main areas of cerebral cortex Responsible for the understanding of spoken and written language. It is considered the center of receptive language.
Usually, but not always, it is in the left hemisphere . This is true for 90% of right-handed people and about 70% of left-handed people.
In particular, the Wernicke area encompasses the back of the Temporal lobe left. However, the exact location and extent of this area has been a controversial subject among scientists.
Recent studies have shown that the Wernicke area is active in deaf people who communicate with sign language. This indicates that the Wernicke area is not only used for spoken language, but for any language modality.
Its name is due to that was discovered by the German neurologist Karl Wernicke in 1874. This scientist discovered this area while observing people who had damages in the back of the temporal lobe of the brain .
People who are injured in the Wernicke area may develop a condition called Wernicke's aphasia . It is characterized by the impossibility of understanding the language, repeating words or phrases, despite having preserved the articulation of speech sounds.
Discovery of the Wernicke area
Many of the scientists who study the brain come to conclusions by observing patients with brain damage.
In this way, they examine patients who have suffered an injury or pathology that affects the brain, and compare them with healthy people.
In this context is framed the famous discovery made by Paul Broca. In 1861, this neuroscientist studied the brain of a patient who could only utter the word"Tan." Although he understood the spoken language, he could only say that word.
Broca found that his patient had an injury to the third frontal gyrus. Suggesting that this area was responsible for controlling speech.
In later studies he confirmed his hypotheses, taking the name this part of the brain of" Broca area ". Broca's studies gave great impetus to the study of the anatomical bases of language.
Shortly after, Karl Wernicke Made a similar discovery. He noted that his patients were not able to speak correctly. Although they spoke well and retained some grammatical structure, the speech was meaningless and difficult to understand.
It seems that what happened to these patients is that they could not understand the language . And, therefore, they could not maintain a smooth conversation.
Wernicke found in them lesions in the brain in the left hemisphere , But on the back of the Temporal lobe
In 1874, he published a work on aphasia that some authors consider as the first neurolinguistic theory. This scientist proposed that there is a"center for the auditory images of words", which is located in the first temporal convolution. This center allows us to understand the language we hear.
Wernicke described the first connectionist model of the neural bases of language. According to this perspective, language arises through the joint work of several centers of language that are connected to each other.
Wernicke's thesis argues that there are two anatomical locations for language. The first is the anterior area, which is on the back of the Frontal lobe ( Broca area ). This area contains"memories"of speech movements, thus controlling the production of language.
The second would be the one known as the Wernicke area, located in the posterior temporal lobe. In it would be the"images of the sounds", that is, that deals with processing the words we hear and give them meaning.
The Wernicke area is usually located in the left hemisphere, specifically in the temporal lobe.
It corresponds to the Areas of Brodmann 21 and 22, encompassing the posterior region of the upper temporal gyrus. This zone of our brain includes the auditory cortex and the lateral sulcus, that part where the temporal lobe and the parietal converge.
However, its exact extent is unclear and there seems to be disagreement among authors. Sometimes the primary auditory cortex and other nearby areas are included. For example, the areas of Brodmann 39 and 40, Parietal lobe .
These areas have been associated with reading and semantic aspects of language.
The Wernicke area is connected to another region of the brain called Broca area . This zone is situated in the lower part of the left hemisphere of the frontal lobe and controls the motor functions involved with speech production.
The difference between the area of Broca and the area of Wernicke is that the first is mainly responsible for planning the production of speech, while the second receives the language and interprets it.
The Broca area and the Wernicke area are joined through a structure called an arched fascicle, which is a large bundle of nerve fibers.
Although recent studies have shown that these two areas are also connected by another structure called"Geschwind territory". It is a kind of parallel path that circulates through the lower parietal lobe.
These two areas, Broca's and Wernicke's, allow us to speak, interpret, process and understand spoken and written language.
Wernicke area and language models
Many authors have attempted to explain how the Wernicke area participates in language and connects with other structures.
Next, the most prominent language models describing the possible role of the Wernicke area are described.
This was the first model of organization of the cerebral functions of language. It was proposed by Norman Geschwind from the studies of Wernicke.
According to this model, each of the characteristics of the language as the perception, the understanding, the production, etc. They are managed by a specific area of the brain that communicates with the others by a series of connections.
According to this model, language disorders arise due to damage in that network of connections between the different modules.
When the spoken word is heard, the auditory signal is first processed in the primary auditory cortex of the brain. It is then sent to the Wernicke area. There, the structure of this signal (its sounds) is associated with the representation of the word stored in memory. Thus we can understand its meaning.
When a word is read aloud, something similar happens, although the information is perceived in the visual cortex initially. Then it is transferred to the angular gyrus, and from there it travels to Wernicke's area.
Whether you hear a word or read aloud, the mental lexicon of the Wernicke area recognizes it and interprets it in context.
For the speech to be given, this information is transmitted to the Broca area, which is in charge of controlling the pronunciation process. The signals on the motor sequences are then sent to the motor cortex that controls the muscles to be able to emit speech.
The Wernicke-Geschwind model is then based on the anatomical location of specific brain areas, which have different functions.
Although this model is very useful for explaining primary language disorders such as Broca's aphasia or Wernicke's aphasia, it does not explain other partial disorders.
In addition, it is hypothesized that each of these areas are connected in series. That is, each previous step must be completed before moving on to the next, something that does not seem to happen in all cases.
The American neurologist Marsel Mesulam proposed an alternative to the previous model. He defended the existence of a hierarchy of networks in which information is processed according to its complexity.
Thus, when performing simple language processes such as reciting the days of the week in order, the motor and premotor areas of the language are directly activated. However, when something that requires more semantic and phonological analysis is expressed, other areas will play a role.
Language would be the result of the synchronized activity of large neural networks. These are constructed by diverse cortical and subcortical regions, as well as by the routes that connect them.
It is not denied then that a localized lesion can generate a certain type of aphasia. What is denied is to attribute to a single area of the brain the loss of a whole linguistic function.
Model of Damasio and Damasio
It is a model that works with interrelated systems. The first system is called"system of concepts"that allows the person to interact with their environment.
Anatomically it would be represented in the associative areas and in the motor areas, including the limbic system and the hippocampus .
Another system would be the"linguistic system"that is responsible for processing language, including phonemic representations and syntactic rules.
There would also be an"intermediate system"that would connect previous systems. That is, the general concepts with their linguistic representations.
The main functions of the Wernicke area are related to processes of reception and comprehension of language.
Through several experiments using images of the brain, we have found three zones in the Wernicke area that are activated according to the function performed:
- One is activated when words that we emit ourselves are pronounced.
- The second responds to words spoken by another person, but also activated when remembering a list of different words.
- While, the third, relates to the planning of the production of speech.
This states that Wernicke's general goal is to represent phonetic sequences (sounds). Whether we hear from other people, those we generate ourselves or those remembered by our memory.
When we read a book, we do not store images of words in our memory, but rather, we remember words in the form of language.
This happens because what we perceive through our senses usually turns into language once processed. Subsequently, it is stored in memory with that"format".
The Wernicke area is the main area of the brain that interprets the language spoken. The first way we learn language is through the sounds of speech. That explains their closeness and connection with the primary and secondary auditory areas of the temporal lobe.
In short, the Wernicke area is responsible for the recognition, interpretation, compression and semantic processing of language. Whether spoken or written. In fact, this area is also involved in both reading and writing.
Injuries in the Wernicke area
When an injury occurs in the Wernicke area, it is expected that certain alterations in the understanding of the language will be found.
The most typical consequence of damage in this area is Wernicke's aphasia. It consists of difficulties in understanding what he hears while preserving the pronunciation of phonemes.
By not understanding the language, they find it difficult to construct a discourse that has a coherent meaning. Although it articulates without problems the sounds of the words.
More specifically, an injury in the Wernicke area would cause:
- Problems to differentiate the phonemes from the language (that is, the sounds of the language). This directly causes speech not to be understood.
- Due to difficulties in identifying the sounds of language, it is common for these patients to join words incoherently.
- Due to the above, neither will be able to evoke the graphic representations of the phonemes, having altered the writing.
However, there are authors who point out that for the appearance of Wernicke's aphasia, more areas of the brain should be damaged. In particular, adjacent areas. This is manifested by deficits that also encompass both comprehension and part of the spoken, gestural and written expression.
Instead, they indicate that a localized lesion in the Wernicke area would exclusively produce a condition called"pure deafness for words." It seems to affect only the reception of the language heard, so that these patients understand the written language better.
In addition, they have preserved the identification of non-verbal sounds (such as a siren, a sneeze...) and writing.
It is important to note that there are other areas in the brain that have interpretive abilities. The patient can help himself to recover his function. They consist of some zones of the temporal lobe and the angular gyrus of the opposite hemisphere.
- Ardila, A., Bernal, B., & Rosselli, M. (2016). How extended is Wernicke's area? Meta-analytic connectivity study of BA20 and integrative proposal. Neuroscience journal, 2016.
- Binder, J.R. (2015). The Wernicke area: Modern evidence and a reinterpretation. Neurology, 85 (24), 2170-2175.
- Bogen, J.E., & Bogen, G. M. (1976). Wernicke's region-where is it? Annals of the New York Academy of Sciences, 280 (1), 834-843.
- BROCA'S AREA, WERNICKE'S AREA, AND OTHER LANGUAGE-PROCESSING AREAS IN THE BRAIN. (S.f.). Retrieved on February 21, 2017, from The Brain from top to bottom: http://thebrain.mcgill.ca/flash/d/d_10/d_10_cr/d_10_cr_lan.html
- Neuroscience infographics: Wernicke area. (S.f.). Retrieved on February 21, 2017, from Asociación Educar para el Desarrollo Humano: asociacioneducar.com.
- Ropper, A.H., Brown, R.H., Adams, R. D., & Victor, M. (2007). Neurology Principles of Adams and Victor (8th ed.). Mexico; Madrid etc.: McGraw Hill.
- Román Lapuente, F., & Sánchez López, M. &. (S.f.). UNIT 5: LANGUAGE, AFFAIAS AND RELATED DISORDERS. Retrieved on February 21, 2017, from University of Murcia: ocw.um.es.
- Wernicke's Area. (June 2, 2016). Retrieved from"Biology: biology.about.com".
- Wernicke's Area: Function & Location. (S.f.). Retrieved on February 21, 2017, from Study: study.com.
- What Is Wernicke's Area? (S.f.). Retrieved on February 21, 2017 from Verywell: verywell.com.
- Wise, R., Scott, S., Blank, S., Mummery, C., Murphy, K., & Warburton, E. (n.d). Separate neural subsystems within 'Wernicke's area'. Brain, 12483-95.
- Wright, A. (s.f.). Chapter 8: Higher Cortical Functions: Language. Retrieved on February 21, 2017, from Neuroscience: neuroscience.uth.tmc.edu.