Charleston Irebaria
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Chapter 11, Draft
Wernicke’s and Broca’s Area
How the brain understands speech and language is one of the oldest and interesting questions in psychology today. Carl Wernicke was an influential member of the nineteenth century German School of Neuropsychiatry. Wernicke made major discoveries in brain anatomy and pathology. He believed that abnormalities could be localized to specific regions of the cerebral cortex. Wernicke was one of the first to conceive brain function as dependent on neutral pathways that connected different regions of the brain. He determined the dominance of left and right brain hemispheres. He is the person behind Wernicke’s aphasia, a topic to be discussed later. Paul Broca was a surgeon closely associated with the development of modern day pathology. Broca studied brain lesions and contributed significantly to the understanding of the origins of aphasia. He further proved the localization of brain function, rather than just a singular organ. Wernicke’s area is an important region of the brain that allows for language development. It is essential for speech comprehension, and any damage to this area will lead to impairments in language development or usage known as Wernicke’s Aphasia. Broca’s area is a part of the brain that gives you the ability to control language, such as the motor aspects of language production. Damage to this area results in a limited ability to speak. There are many factors when it comes to language comprehension and Wernicke’s and Broca’s area are very important when it comes to language as these two areas work together to give humans the ability produce and comprehend language.
Wernicke’s area has a main function of allowing language comprehension, recognition, interpretation, and processing. Language is heard then stimuli is directed to the primary auditory cortex, which is then sent to the Wernicke area to be processed and turned into a word with a meaning through memory. The same process is achieved when language is read aloud. The initial stimulus is directed to the primary visual cortex, then goes to the angular gyrus where it is organized into language and then into thoughts. Once done, the stimulus is transferred to Wernicke’s area and a meaning is associated.
Wernicke’s aphasia is characterized by the impaired ability to remember the names of objects and impaired language comprehension and is caused by cell death in the posterior superior areas of the temporal lobe. As a result, this affects language. Those with aphasia will speak incoherently due to the fact that they lack the ability to understand spoken language. This could be caused by strokes that block blood supply to Wernicke’s area, which is then coupled with cell death. This can also be classified as fluent aphasia when the patient is still able to speak smoothly (Hillis 2001). Information is heard through the auditory cortex, yet when it reaches Wernicke’s area, information is not able to translate into meaningful words. Individuals are still able to speak, but with no meaning.
Broca’s area is the name given to the area of the brain that is mostly responsible for the production and processing of speech. Broca’s area aids in the control of neurons responsible for facial movement. It also allows for humans to understand complex language structure. Paul Broca examined patients with speech impediments postmortem. All patients had damage in the same area of the brain. Damage was found on the frontal lobe of the left lateral cerebral cortex next to the motor cortex. Broca was first to determine the brain as having localized functions and led way to the theory of brain specialization (Kalat, 2007). Over a century of research has confirmed Broca’s original findings and has validated the idea that certain brain processes are in fact exclusive and located in select parts of the brain.
Broca’s area is divided into two sections, the Par Triangularis and Par Opercularis. The Par Triangularis is thought to predominantly control verbal behavior while the Pars Opercularis is thought to control organs responsible for production and articulation of language. This makes sense as the close proximity to the primary motor cortex in controlling general and fine motions of facial features and speech. Fine motor control could also be closely related to position.
Broca’s area is also thought to control linguistic mechanisms such as action perception, working memory, syntactic complexity, and syntactic movement. Action perception refers to mechanisms that allow for association of “action observation and execution”, or the planning of movements needed to articulate a thought. Working memory refers to verbal working memory responsible for controlling speech organs and how they move to allow for clear speech. Syntactic complexity refers to processing of complex input of phrases or sentences. Syntactic movement refers to the computation of syntactic movement in reception, or the ability to move and rearrange words in a written sentence and still see it as meaningful (Grodzinsky and Santi 2008).
Broca’s area has shown its importance in the development and use of language but as with other parts of the brain, lesions in these specific areas can result in specific neurological conditions. The most well know condition is known as Broca’s aphasia. Also known as non-fluent aphasia, it is usually caused by a stroke and results in loss of fluidity in speech, repetition and loss of grammatical correctness when speaking. Affected individuals have no problem understanding and processing language but cannot generate the same. Broca's aphasia causes difficulty with repetition and a severe impairment in writing. If there is damage to both Wernicke's area and Broca's area, global aphasia can occur (Coslett 1984). Global aphasia affects all areas of speech. Patients with this condition are only able to speak a few words. They cannot read, write, or repeat words. Those with Broca’s aphasia often become frustrated due to the fact that they cannot articulate what they think or say.
Broca's area serves as a nexus for higher speech processes and all the functions associated with complex conversation. Without the structure that we call Broca's area, our language, gesticulation and complex social interactions might not exist in the same state that they exist today. There are many factors that contribute to the overall process of language comprehension. The complete processing of language requires many additional brain regions such as Broca's area to properly produce and comprehend language. Neurologist Carl Wernicke demonstrated that Wernicke's area is critical in understanding language that is spoken and written through his findings. These areas of the brain, like any other, can be very sensitive to disease or damage.
References
Coslett. (2015). Global Aphasia. In The Oxford Handbook of Aphasia and Language Disorders.
New York, NY: Oxford.
Grodzinsky, Y., & Santi. (2014, November). Retrieved March 07, 2018, from
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4252493/
Hillis, A. E., Wityk, R. J., Tuffiash, E., Beauchamp, N. J., Jacobs, M. A., Barker, P. B., and
Selnes, O. A. (2001) Hypoperfusion of Wernicke’s area predicts severity of semantic
deficit in actual stroke. Ann Neurol., 50: 561-566. Doi:10.1002/ana.1265
Kalat. (2010). Biochemical Systems, the Brain, and Behavior. In Human Behavior in the Social
Environment (4th ed.). Belmont, CA: Cengage Learning.