The Brain and Language

In Glogpedia

by W10Myers
Last updated 4 years ago

Discipline:
Science
Subject:
Human Anatomy

Toggle fullscreen Print glog
The Brain and Language

The Brain is Organized for Language.The human brain is divided into two hemispheres, connected by the corpus callosum, which allows the left and right hemispheres to work hand in hand to control the body. Contralateral brain function means that the right hemisphere controls the left side of the body and vis-versa. Isplateral brain function, when one side of the brain functions to control the same side of the body, is not as strong and as quick as contralateral function. The left hemisphere largely controls language, although the right hemisphere plays a part in early language development. The two main areas in the left hemisphere to control language are Broca's area and Wernicke's area.

Studies of aphasia indicate that the mental lexicon is organized phonologically (by sound) and semantically (by meaning). The aphasics will often subsitute words that sound similar or have similar meanings. This theory is supported as well by the observation of people with reading disorders, called dyslexics.Just like aphasics make incorrect word substitutions, so do acquired dyslexics (once normal readers who developed brain lesions). Both types also can be agrammatic and leave off funtion words.Interestingly, when a funtion word (e.i- I) has a homophone that is a content word (e.i- eye), the agrammatic will recall and pronounce the content word, but is unable to use the function word. Note: Developmental dyslexics have difficulty learning to read, but do not struggle with word subsitutions. More proof of laterization of language lies in Japanese speakers of Kana (symbols related to sounds) and Kanji (symbols related to images). Studies of brain damage shows that Kana is tied to left brain function whereas Kanji is controled by the right hemisphere.

Specific Language Impairment (SLI) is an impairment that occurs without lesions and nonlinguistic symptoms. -trouble with function words-specific grammar errors-trouble with inflectional suffixes, such as markers of tense and agreement.-Language can be impaired while intelligence is intact-Supports view that grammatical faculty is a separate cognitive system.Linguistic Savants are basically the opposite of SLI children. They are intellectually handicapped and yet, have highly complex grammar, sometimes to an amazing degree. - case studies: Laura and Christopher

SLI, Dyslexia, twin studies and other disorders point to language having a genetic basis. The Critical-age Hypothesis assumes that language is biological and that it must be triggered and acquired during a critical period from birth until middle childhood. Children who do not acquire language (verbal or signed) during this time develop atypical patterns of brain laterilization and do not fully develop grammatical skills. They can not grasp function words, and have similar symptoms to split brain and left hemispherectomy patients. This is seen and studied when children have experienced extreme isolation, either in nature (i.e- Victor, Amala and Kamala) or deliberately (i.e- Genie) or because of misdiagnosis (i.e- Chelsea). Chelsea proved that the critical-age theory applies to deaf children with signing as well.

Disney made a linguistic mistake. Tarzan was isolated from human language until adulthood. He would never have aquired grammatical language as he did in the film! Monkey's can't teach grammar and Jane came along too late. Sorry, Tarzan.

Some animals also have critical periods and support the idea of critical-age theory.Some birds must acquire their bird song and its complexities before a certain age or they will never learn it. Other birds are born with their song and do not ever need to hear an adult sing the song. Although the birds do not have language, their song acqusition supports the idea that language is biological and must be triggered and obtained by a critical age.

Dichotic Listening is a technique using auditory signals to observe the individual behaviors of the human brain hemispheres. This technique has shown:- Contralateral pathways (across hemispheres) are stronger than ipslateral pathways (same side) -Language is lateralized-The left hemisphere is superior for processing linguistic sounds- The right hemisphere is superior for processing nonlinguistic sounds, such as music. ERPs (Event-Related brain potentionals) trace electrical signals in the brain:-shows that meaningless sentences still trigger the language side of the brain.-shows the left side is sensitive to grammar. -Newborns respond the same was as adults.-Left hemisphere is primed for language at birth.

The development of human language is thought to have occured because of the evolution of the brain, but how is debated. Noam Chomsky and Stephen Jay Gould expressed that the brain could have become so complex that language was a biproduct, while others took a more Darwinian approach by saying that the brain is wired specifically for language and that it can not have simply happened by neurons being packed tightly together without purpose of language.

Whitney

Tip of the Tongue Phenomenon (TOT) is when a person occasionally can't recall a word, but aphasics often suffer from sever anomia, the inability to recal a word. Deaf patients experience the same linguistics symptoms as hearing aphasics. These studies show that language is a separate cognitive module, which means that linguistically impared people are no less intilligent that others.

Broca's area affects syntactic elements of language. -Agrammatic (lacks funtion words) - Anomia (problem recalling words)Wenicke's area affects semantic elements of language. -Nonscense words -Grammatically correct, but strings of words don't make scense together -Incoherent

Aphasia is a language disorder that results from brain damage caused by disease or trauma. By studying aphasia, much has been learned about laterization, the term used to refer to the localization of function to one hemisphere of the brain or the other.Both Broca's and Wernicke's aphasia point to a modular organization of language in the brain. Damage to different areas of the brain result in different linguistic impairments. Broca's Aphasia =Agrammatic Aphasia Syntactic errorsWernicke's Aphasia= Jargon Aphasia Semantic errors

Adults with severed hemispheres, or split brain, lose the ability for their hemispheres to communicate. The hemispheres then act independently of each other, which shows scientist which hemisphere does a better job at controlling different functions. The left hemisphere does a much better job with language, although both hemispheres are able to complete tasks, the left can explain why better than the right.

Aphasia has been observed throughout history, but with technology, scientists have a much more revealing view of the brain and language. CT scans MRIsPETs fMRIsSPECTs MEGsERPsThe above technologies have all revealed important information about localized brain damage and linguistic tasks. Modern medicine also reveals the plasticity of the brain, meaning that at early stages it is flexible. If the left hemisphere is removed surgically through a hemispherectomy, before language aquisition, the right hemisphere can take over language function. If the surgery takes place after language is aquired, language function is severly crippled for life. Hemispherectomies have also shown that the right hemisphere plays a role in early language development. Story of Hemespherectomy in three year old girl:https://www.youtube.com/watch?v=VaDlLD97CLM

The Brain

& Language

Myers


Comments

    There are no comments for this Glog.