The Brain: Broca’s And Wernicke’s Areas And The Circle Of Willis
Linda Crampton is a writer and teacher with a first-class honors degree in biology. She often writes about the scientific basis of disease.
This illustration shows colour-coded lobes of the cerebral cortex. Pink = frontal lobe, blue = parietal lobe, orange = temporal lobe, green = occipital lobe
Wernicke’s Area: Speech Interpretation
Location: Temporal lobe; at the end of the lateral fissure, where the temporal lobe meets the parietal lobe.Main Function:;Speech comprehension.Result of Damage: People who suffer damage to Wernickes area are not able to understand speech. They can often produce speak fluently, but their words may not make sense.
Take a look at the video below to see how someone speaks when they have Wernickes aphasia.
What do you notice about Bryons ability to communicate? While you listen, reflect on some of the same questions as we did for Brocas aphasia.
- ; Does he appear to understand what is being spoken to him?;
- ; Do the words he responds with make sense in the context of the conversation?
- ; Does he have trouble saying individual words?
- ; Does he have trouble saying multiple words together in a sentence?
- ; Does he stutter or have long pauses between words?
- Do you think it would be possible to have a meaningful conversation with Bryon?
History Of Brocas Area
Paul Broca was a French physician who discovered what would later be named as Brocaâ area. In 1861, Broca met a patient called Louis Victor Leborgne, who would also be known as âTanâ.
Broca found that Leborgne had difficulties with producing speech, often wanting to communicate his thoughts but being unable to. Leborgne was also known as âTanâ since this was one of the only words that he could produce, often repeating the word twice, saying âTan tanâ.
Leborgne often used gestures to try to communicate to Broca, but sometimes became frustrated at his inability to express himself.At the time, there was a lot of debate as to whether there were specific areas of the brain specialized for certain functions, or if the entire brain was utilized for every function, known as a holistic viewpoint.
There was some evidence emerging that suggested that speech may be localized to the frontal lobes. Broca intended to investigate this further as he held the idea himself that brain functions may be specialized to certain areas.
When Leborgne died, Broca completed a post-mortem of his brain to investigate any abnormalities. As Broca lived in a time before modern neuroimaging techniques existed, one of the only methods of discovering brain differences at the time was to wait until patients had died to be able to view their brains.
As with the case of Leborgne, an individual with Brocaâs aphasia may only be able to produce two words at a time, often repeating the same word.
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Wernickes Area Vs Brocas Area
Wernickes Aphasia doesnt affect our ability to vocalize. This is due to Wernickes early theory – the part of the brain known as Wernickes area strictly comprehends language. The area that tells the mouth to vocalize is known as Brocas Area.;
Wernickes research came about 10 years after similar discoveries were made by French neuroscientist Paul Broca. Broca had been working with patients who could comprehend language, but didnt have the ability to produce speech. Like Wernicke, Broca found lesions in the brains of these patients. But the lesions were located in a slightly different location. This part of the brain, responsible for speech production, is now known as Brocas area.;
Brocas area is located on the other side of the auditory and motor cortex.;
What Part Of The Brain Controls Language And Speech
To be gifted with language is to be able to both understand and respond to someone. In other words, the faculty of language covers comprehension and utterance. For spoken language, you have to be able on the one hand to pass from sound to meaning, and on the other hand, then, from the words thought to the words spoken, from the thought to the voice. These processes obviously depend on learning, society and culture, but they also have cerebral underpinnings part of the brain controls language and speech:
Each hemisphere of the cerebrum can also be divided into regions called lobes, which include the frontal, parietal, temporal, and occipital lobes.
The lobes located in the front and side of your brain, the frontal lobes and the temporal lobes, are primarily involved in speech formation and understanding. The cerebral cortex is responsible for integrating sensory impulses, directing motor activity, and controlling higher intellectual functions.
Brocas area: source of speech production
This discovery marks the beginning of the identification of areas of the brain related to different facets of human language. Patients suffering from aphasia have enabled anatomists and then neuropsychologists to refine their knowledge of cerebral language supports, the study of different cases making it possible to identify different cerebral areas endowed with specific functions.
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Wernicke’s Area Location And Function
Wernicke’s area is the region of the brain that is important for language development. It is located in the temporal lobe on the left side of the brain and is responsible for the comprehension of speech, while Broca’s area is related to the production of speech. Language development;or usage can be seriously impaired by damage to Wernicke’s area of the brain.
When this area of the brain is damaged, a disorder known as Wernicke’s aphasia;can result, with the person being able to speak in phrases that sound fluent yet lack meaning.
General Inability To Speak And Understand Language
Widespread damage to the brains language centers can result in global aphasia. People with global aphasia will have an extremely hard time expressing and understanding language.
People with neurodegenerative diseases, such as Alzheimers disease, often experience loss of speech slowly over time. This is called primary progressive aphasia .
PPA is not Alzheimers disease but can be a symptom of Alzheimers disease. PPA can also be an isolated disorder without the other symptoms of Alzheimers disease. Some people with PPA have normal memories and can continue leisure activities and sometimes even work.
Unlike aphasia that results from stroke or brain trauma, PPA results from slow deterioration of one or more areas of the brain used in speech and language.
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Difference Between Brocas Area And Wernickes Area In The Brain
The main task of Broca’s area is to generate meaningful language so that the person can be speak sensibly and fluently. The Wernicke’s area is responsible for understanding the statements made by the speaker. It is essentially involved in language processing. The following Bodytomy post gives a comparison between the two.
The main task of Brocas area is to generate meaningful language so that the person can be speak sensibly and fluently. The Wernickes area is responsible for understanding the statements made by the speaker. It is essentially involved in language processing. The following Bodytomy post gives a comparison between the two.
Symptoms And Signs Of Brocas Aphasia
The basic signs of Brocas aphasia are related to speech production.;People with this syndrome have;severe difficulties finding words and articulating sentences;fluently, and speech prosody is also affected, which causes speech to be monotonous.;The writing is equally affected.
In the context of this disorder;, people often speak of telegraphic speech;to refer to the way they express themselves to those who suffer from it: they pause a lot because they have many difficulties in articulating words that are not content, that is, they communicate mainly through sequences of nouns and verbs.
The intensity of these symptoms depends on the severity of the injury;;while in some cases only mild anomie, moderate reductions in expressive fluency and the phenomenon of foreign accent appear, in others the person may be unable to emit any word.;In most cases at least the most formulaic expressions are retained.
Since the regions related to Brocas aphasia are involved in motor skills, it is not surprising that the brain lesions that cause it also cause motor signs.;Highlights include hemiparesis , apraxia and;dysarthria, which affects pronunciation;.
In a synthetic way we can say that the main characteristics of Brocas aphasia are the following:
- Lack of fluency in spontaneous language
- Alterations in writing
- Maintenance of listening and reading comprehension
- Word repetition deficit
- Problems remembering words, such as object names
- Associated motor disorders
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Wernicke’s Area: Location Function And All About Wernicke’s Area
Tripboba.com – Wernicke’s area is one of cerebral cortex parts that contains motor neurons linked to comprehension of speech. It is usually known as Wernicke’s speech area.
German Neurologist namely Carl Wernicke was the first person that described the Wernicke area. He did it in 1874.
The exact location of the area is near the auditory cortex. It is in the posterior third of the upper temporal convolution of the left hemisphere of the brain. Wernicke’s area is considered an important part of the brain where language comprehension occurs.
This article will explain more about the history behind the discovery of Wernicke’s area, its structure and function, as well as a possible condition of damaged Wernicke’s area.
Damage Of The Wernickes Area
Aphasia is the loss or disruption of language skills that were already previously acquired and functional. Aphasia is a condition usually caused by a brain injury. Injuries to the brain especially occur as a result of a stroke, but can also occur as a result of physical injuries, tumors, dementias, infectious brain diseases, etc.
In more medical terms, speech disorders resulting from damage to the corresponding speech centers in the dominant cerebral hemisphere of the cerebral cortex and their subcortical connections are called aphasia or, if the impairment is incomplete, dysphasia.
Depending on the part of the brain that is affected by the injury, a patient with aphasia partially or completely loses one or more linguistic abilities. Language skills include the production of spontaneous speech, speech comprehension, the ability to name items, repetition, reading, and writing.
Aphasia can also be accompanied by cognitive function impairment, such as loss of attention, memory problems, and thinking disorders. In addition to the spoken languages, sign language functions can also be damaged by aphasia. Sign languages also represent structured linguistic systems and have a phonological, morphological, and syntactic level.
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The Function Of The Wernicke’s Area
As already stated, the key function of the Wernickes Area is understanding speech. It processes the meanings of sounds. However, research done in recent years has shown that there are more than two speech areas in the dominant cerebral hemisphere.
Moreover, the entire group of areas decodes the structure of difficult sentences, the second one decodes the structure of easy, simple sentences, and the third group of areas is responsible for the meaning of the words. These processes happen whether we talk or listen.
These regions are positioned in the Brocas and the Wernickes areas, as well as the anterior portion of the temporal lobe. Furthermore, they are located in several parts of the anterior lobe, as well as the inferior parietal lobe. Remarkably, according to what we know today, the occipital lobe is not involved in speech processing at all.
The Discovery Of The Wernicke Area
In the 19th century, neuroscientists were trying to discover and localize functions and abilities in our brain and relate them to their responsible centers. One of the areas of their interest was language production, processing, and understanding.;
Paul Broca was one of the pioneers when it comes to language centers research. In the early 1870s, he made a remarkable discovery. Namely, he identified the brain region responsible for language production.
Paul Broca also made research on patients with problems in producing language, especially in cases when they do understand the language but cannot speak. Broca found that lesions in a specific part of the frontal lobe lead to that very disorder. It is this brain area that we today know as the Broca’s area.
The other key neuroscientist of the 19th century is German neurologist, Carl Wernicke, as mentioned in the introduction. This neurologist was interested in patients with a similar, yet so different problem.
Wernickes patients were able to speak but their speech was meaningless. In addition, they were not able to understand, i.e. comprehend language. Wernicke was devoted to examining the brains of these patients. He found lesions in an area located between the temporal, parietal, and occipital lobes, we today know as the Wernickes area .
It was proven that this brain region is responsible for language comprehension and the production of meaningful speech.
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Components Of The Circle Of Willis
The arteries that make up the circle of Willis are divided into an anterior group and a posterior group . The orientation of the circle is shown in the illustration below.
In order to make the illustrations above and below easier to understand, the arteries are cut off at the ends where they disappear from view, change direction, or are no longer considered to be part of the circle of Willis. The blood vessels that make up the circulatory system are actually continuous. They branch and merge and change in diameter and direction, but they never simply end.
The anterior group of arteries in the circle of Willis consists of the following blood vessels.
- Right and left anterior cerebral artery
- Anterior communicating artery
- Right and left internal carotid artery
The posterior group consists of these vessels.
- Right and left posterior communicating artery
- The horizontal parts of the right and left posterior cerebral arteries
- The tip of the basilar artery
Blood is sent from the heart to the brain through the two internal carotid arteries and the two vertebral arteries.
Artery positions in relation to the undersurface of the brain
Brain Injury And Speech
What happens if one or more of these parts is injured, damaged, or abnormal?
If you have a problem speaking or understanding speech, its a condition called aphasia. If you have trouble putting together the correct muscle movements necessary to produce speech, its a condition called .
Symptoms of aphasia or apraxia depend on where the damage occurs in the brain and the severity of the damage. These symptoms include:
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How Wernickes Area Is Viewed Now
More current research on these processes shows that the Wernicke-Geschwind Model may not be telling the full story about auditory and visual cognition. In fact, some researchers believe that Wernickes area has more of a role in speech production than was originally proposed by Wernicke. If this is the case, the Wernickes Area and Brocas area may not be so different after all.;
The Wernicke Area Is Critical For Speech Production
Although the end product of speech production is a series of muscle movements, the brain mechanisms involved in speech production should not be seen as limited to motor commands that move muscles. Before such commands can be sent, the speaker must momentarily activate knowledge about the sequence of consonant and vowel speech sounds that form the word to be spoken. This mental stage prior to articulation is known as phonologic retrieval. Its existence can be demonstrated by the fact that one knows that the word snow rhymes with blow but not with plow without needing to say these words aloud. In the jargon of language scientists, this knowledge reflects activation of a phonologic representation or mental image of the sounds comprising the words. Partial disruption of this phonologic retrieval process causes a speech production impairment called phonemic paraphasia, in which the phonemes of the spoken word are chosen incorrectly or are incorrectly ordered., Phonemic paraphasia is a cardinal feature of both Wernicke aphasia and conduction aphasia. Although these are fluent aphasias because there is no slowing of overall word output, the paraphasic component is nevertheless a deficit of speech production, not speech comprehension. Thus Wernicke aphasia, though often thought of as a syndrome affecting comprehension, also includes a prominent speech production impairment.
Involvement of the Wernicke area in speech production
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Brain Areas That Control Language And Speech
Several areas of the brain must function together in order for a person to develop, use, and understand language.
Without the brain, there would be no language. The human brain has a few areas that are specific to language processing and production. When these areas are damaged or injured, capabilities for speaking or understanding can be lost, a disorder known as aphasia. These areas must function together in order for a person to develop, use, and understand language.
Brocas area, located in the frontal lobe of the brain, is linked to speech production, and recent studies have shown that it also plays a significant role in language comprehension. Brocas area works in conjunction with working memory to allow a person to use verbal expression and spoken words. Damage to Brocas area can result in productive aphasia , or an inability to speak. Patients with Brocas can often still understand language, but they cannot speak fluently.
Wernickes area, located in the cerebral cortex, is the part of the brain involved in understanding written and spoken language. Damage to this area results in receptive aphasia . This type of aphasia manifests itself as a loss of comprehension, so sometimes while the patient can apparently still speak, their language is nonsensical and incomprehensible.
The angular gyrus, located in the parietal lobe of the brain, is responsible for several language processes, including number processing, spatial recognition, and attention.