语言学概论-brain-and-language

1、Brain and Language,The Human Brain,Introduction The complexities of human cognitive abilities and language acquisition Brain is the source of human language and cognition.,The most complex organ of the body Cortex (gray matter) decision-making memories grammar White matter Contralateral function,The

2、 Localization of Language,Which parts of the brain are responsible for linguistic abilities? Franz Joseph Gall Localization Organology(phrenology) Brain is not a uniform mass.,Aphasia,Relationship between brain and language Language disorder caused by disease or trauma Brocas area v.s. Wernickes are

3、a Lateralization,Most aphasics do not show total language loss. The language disorder is generally related to the location of the brain damage. Brocas aphasia injuries to the left frontal lobe Wernickes aphasia injuries to the left temporal lobe,Brocas area,Wernickes area,I. Brocas aphasia (agrammat

4、ic aphasia),Syndromes : A. Labored speech B. Word-finding difficulties C. Problems in forming sentences with the rules of syntax,D. Language produced is often agrammatic Q: What is “agrammatic” ? A: It frequently lacks articles, prepositions, pronouns, auxiliary verbs. lacks function words The omiss

5、ion of function words in the speech of agrammatic aphasics shows that function words are mentally distinct from content words.,E. May typically omit inflections the past tense suffix ed e.g. I watch TV for three hours this morning. the third person singular verb ending s e.g. She like playing the pi

6、ano.,ed,s,F. Have difficulty understanding complex sentences in which they cannot rely on their real-world knowledge. more difficulty for aphasia people: e.g. Which girl did the boy kiss? less difficulty for aphasia people: e.g. Which book did the boy read?,II. Wernickes aphasia,Wernickes aphasics c

7、an produce fluent speech and adhere to the rules of syntax. Syndromes: A. Their language is often semantically incoherent. fork a need for a schedule when asking about poor vision My wires dont hire right.,B. Have difficulty naming objects presented to them C. Have difficulty choosing words in spont

8、aneous speech often produce jargon and nonsense words,Jargon aphasia,Severe Wernickes aphasia is often referred to as jargon aphasia. Syndrome: substitute new word for original word,Word substitutions that aphasic patients produce also tell us about how words are organized in the mental lexicon. sou

9、nds meaning pool tool table chair sable table boy girl crucial crucible .,III. Acquired dyslexics,Dyslexia: a condition that makes it difficult for someone to read and spell. Acquired dyslexics: people who become dyslexic after brain damage. The similar phenomenon of word substitutions may also happ

10、en to acquired dyslexics. (examples on page 9),The similar syndrome of the omission of function words in the speech also happens to acquired dyslexics.(examples on page 10) These errors show that the mental lexicon has content words and function words in different compartments.,IV. Tip-of-the-tongue

11、 phenomenon,The tip-of the-tongue phenomenon is the failure to retrieve a word from memory, combined with partial recall and the feeling that retrieval is imminent. word-finding difficulties in speaking,TOT,Word finding difficulties is the fate of many aphasics. Anomia: the inability to find words y

12、ou wish to speak,V. Deaf Aphasic patients,Deaf patients with lesions in Brocas area Syndromes: dysfluent and agrammatic sign production Deaf patients with lesions in Wernickes area Syndromes: have fluent but often semantically incoherent sign language,Conclusion,Deaf signers with damage to the left

13、hemisphere show aphasia for sign language similar to the language breakdown in hearing aphasics.,Brain Imaging Technology,Noninvasive brain recording technologies 1.Computer tomography(CT) 2. Magnetic resonance imaging (MRI) Reveal lesions in the living brain shortly after the damage occurs.,3. Posi

14、tron emission tomography(PET) 4.Functional MRI(FmrI) 5.Single photon emission CT(SPECT) Provide images of the brain in action.,.,Other scanning techniques measure metabolic activity in particular areas of the brain 1.Magnetic encephalography (MEG) This technique shows us how the healthy brain reacts

15、 to particular linguistic stimuli.,Separation of the cognitive system,Evidence: 1.fMRL & PET scans Differential activation in the normal brains in just those sites that were damaged in the aphasics. 2. neurological and behavioral findings,Brain Plasticity and Lateralization in Early Life,Lateralizat

16、ion of language to the left hemisphere is a process that begins very early in life. Infant as young as one week show a response right hemisphere music left hemisphere language,The study found: during smiling greater opening of the left side of the mouth during babbling greater opening of the right s

17、ide of the mouth more left hemisphere involvement even at this very early stage of productive language development,the right hemisphere can take over the language functions that would normally reside in the left hemisphere. Hemispherectomy one hemisphere of the brain is surgically removed 2.Treat ot

18、herwise intractable cases of epilepsy,Doing left hemispherectomy After language acquisition has begun In children they experience an initial period of aphasia and then require a linguistic system that is virtually indistinguishable from normal children. In adults They inevitably lose severe language

19、 function,Right hemisphere plays a role in the earliest stages of language acquisition Children with prenatal, perinatal, or childhood brain lesions in the right hemisphere babbling and vocabulary learning in the left hemisphere ability to form phrases and sentences Also, children who undergo right

20、hemisphere hemispherectomy before two years of age dont develop language.,Conclusion,Human brain is essentially designed to specialize for language in the left hemisphere but that the right hemisphere is involved in early language development. Under the right circumstances, the brain is remarkably r

21、esilient and that if brain damage or surgery occurs early in life, normal left hemisphere functions can be taken over by the right hemisphere.,Spilt Brain,review：What is the corpus callosum? What is the word “spilt brain”? A. Definition - an surgical technique to cut some or all corpus callosum of a

22、 person What will happen if people lose their corpus callosum? - no communication between the left and the right hemispheres - function independently,An experiment on split-brain patients to show what will happen to people when the corpus callosum is severed.,What significant information we get from this experiment? - infer to the language lateralization in the left hemisphere - knowing that two hemispheres of brain have different capacities Function of two halves： the right: pattern-matching ta