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tesl 553 language cognition and esl/curriculum development module 5 content 5.1 language and the brain a general brain structure and function why do we have body preferences we have them from infancy and throughout our lives the answer lies in the brain and its structure and function b the hemispheres of the brain the brain is divided into the right and left hemispheres that maintain connection with one another through a bundle of fibres called the corpus callosum the latter is the principal integrator and coordinator of the mental processes carried out in both hemispheres each cerebral hemisphere is divided into four parts or lobes oooo frontal lobe temporal lobe parietal lobe occipital lobe c general functions of each lobe ooood the cortex o it is the covering of each hemisphere frontal lobe cognition temporal lobe hearing parietal lobe general somaesthetic sensing feeling in the arms legs,face etc occipital lobe vision © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development o o it is a furrowed outer layer of cell matter it is concerned with higher brain functions in both humans and animals e size and weight of the brain © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development o regarding the linguistic and intellectual abilities it is not evident exactly how important the actual size and weight of the brain is o o o the brain of the average human adult weights from 1to1.5 kg 2.25 to 3.25 pounds it is the ratio of brain to body size and weight that is important inherent structural differences must also exist for humans which would account for their advanced intellectual functioning and language f the central nervous system and the cerebral cortex o o the brain and the spinal cord make up the central nervous system from the top of the spine upwards are the medulla oblongata the pons varolii the cerebellum and the cerebral cortex ooooooooo the first three are concerned with physical bodily functions breathing heartbeat transmission coordination of movement involuntary reflexes digestion emotion the fourth part of the brain the cortex is concerned with advanced intellectual functioning and language g anatomical asymmetry of the hemispheres o o research has demonstrate that the hemispheres are not identical human infants at birth have a bulge in the left hemisphere near where language is located but not in the corresponding area of the right hemisphere wada clarke and hamm,1975 o asymmetry of the brain is even in the fetus h some differences have been found for adults © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development o in a group of 100 normal humans geschwind and levitsky 1968 demonstrated that wernicke`s area is generally larger than the corresponding area in the right hemisphere i hemispheric structure and function left and right hemispheres control opposite sides of the body the left hemisphere controls the right side of the body right hand right arm right side of the face the right hemisphere controls the left side of the body example stroke j vision ooooo stroke won`t affect vision and hearing the same way cross over controls our organs of sight and hearing field of vision each half of an eye will send what it senses to the opposite hemisphere survival view the divided field-vision and criss-cross connections to the hemispheres have a number of advantages each eye divides into left and right fields © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development oooo left field is connected to the occipital lobe of the right hemisphere right field is connected to the occipital lobe of the left hemisphere both fields are integrated as a whole the divided fields of vision allow for direct sensory input to both hemispheres even with only one functioning eye this is very important because both hemispheres use visual information in different ways k o audition fibres /fibers of the acoustic nerve of each ear distributes the incoming o signal to both hemispheres © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development o fibres from each ear cross over to the other hemisphere while only a small number go directly to the hemisphere which is closet to that ear o the divided pattern is probably related to the fact that the hemispheres specialize in certain sounds o survival function in spite of a partial loss of hearing due to physical damaged in one ear we will still be able to receive sounds this is so since the undamaged ear will send sound signals internally to its opposite hemisphere l hemispheric dominance o o o dominance the phenomenon where one hemisphere is the controlling one typically the left hemisphere dominates the right hemisphere a left-hemisphere dominant person would tend to use the right hand and the right foot while a person who is right-hemisphere dominant would tend to use the left hand and the left foot o about 9 of the population world-wide are left-handed but only about 30 of left-handers have right hemisphere dominance o the lack of strong dominance for left-handers is believed to be a factor contributing to various disorders such as speech disorders reading and writing disorders stuttering and dyslexia o amar klar stipulates that there is a single gene that makes the people right-handed when the gene is defective you have 50 of being right-handed and 50 of being left-handed or ambidextrous m left handers achievement and discrimination o o one who is more skilled with the left hand when performing a task interestingly among left-handers there is a great proportion of artists musicians and writers than found among right-handers o in the twentieth-century u.s.a presidents including truman reagan bush and clinton are left-handers o physicist albert einstein was left-handed dominance is a congenital condition © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development it is present at birth this conditions can be inherited or caused by environmental factors the practice of forcing children who are naturally l.hs to be r.hs not only will not remedy such problems but may serve to worsen them n ambidexterity o o o many countries still force natural l.hs to be r.hs it has not been long since japan stopped such practice in the 1970s those who can use both hands equally well we call ambidextrous those who learn it still tend to sway toward their originally dominant hand ambidextrous renowned people o o o benjamin franklin michelangelo leonardo da vinci genius who devises all sorts of secret writing -it has been reported that the corpus callosum of the left hander and ambidextrous people is 11 larger saunders,undated -saunders claims that an ambidextrous activity like swimming often helps dyslexic children to read and write normally because it balances both hemispheres p sound preferences o speech sounds are differentiated from other types of sounds including music animal sounds and noises o o the two hemispheres specialize in processing speech and non-speech sounds for true right-handers speech sounds are mainly processed in the left hemisphere while music noises and animal sounds are mainly processed in the right hemisphere q lateralized hemispheric functioning © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development lateralization is the separation of functions between the left and right hemispheres -incoming experiences are directed to the left or right hemisphere depending on the nature of those experiences o left-hemisphere specializations -broca`s area wernicke`s area and the angular gyrus are the main language centres o arcuate fasciculus is a tissue that connects broca`s area with wernicke`s area -for 99 of right-handers and about 2/3 of left-handers language is in the left-hemisphere in less than 5 of the us population language is located in the right-hemisphere o -left-hemisphere is concerned with language logical and analytical operations and mathematics r right-hemisphere specializations -the right hemisphere is involved in recognizing emotions recognizing faces and perceiving the structures of things globally without analysis -it deals with music and non-linguistic sounds -it also has some language functions and can take over the complete language functioning of the lefthemisphere © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development s sex differences and lateralization -some studies suggest that females have a thicker left hemisphere and males have a thicker right hemisphere in a volume by philips steele and tanz 1987 it was found that although there are some differences in males and females processing of the language in the brain these do not yield any gender differences in language use in an animal experiment professor marian diamond has shown that injecting sex hormones into young rats can affect the development of the thickness and size of the hemispheres of their brain a study berenbaum hines 1992 deals with human children who had high levels of androgen due to genetic glandular disorder -girls with this condition exposed to androgen as fetuses exhibited a boy toys t split-brain effect o sperry 1982 separated the two hemispheres of the brain by severing the corpus callosum of a number of patients o it was found that split-brain persons could still use speech and writing in the disconnected lefthemisphere but their right hemisphere had little such capacity o when tactile information passed to the left-hemisphere patients were capable of verbally describing objects and talking about the things they had touched o the right-hemisphere was incapable of imagining the sound of a word and patients failed simple rhyming tests o the right-hemisphere was found to be good at spatial tasks preference for u language areas and their functioning broca s area the motor area and speech production pier paul broca © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development french pathologist neurosurgeon and anthropologist born june 28 1824 sainte-foy-la-grande gironde bordeaux died july 9 1880 paris made important contributions to anatomy physiology and anthropology and he was the founder of modern brain surgery associated eponyms broca s angle occipital angle of the parietal lobe broca s aphasia a peculiar form of central language destruction aphasia in which the patient is able to utter only a few simple words and is unable to write even though he knows what he wishes to say broca s area area of the left hemisphere of the brain containing the motor speech area v broca`s area broca discovered an area of the cortex that is involved with the production of speech broca`s area he further noted that the speech area is adjacent to the region of the motor cortex © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development the motor cortex controls the muscles of the articulators of speech the tongue lips jaws,soft palate and vocal cords w the link between broca`s area and the motor areas the speech-production process would begin in broca`s area pass on through the arcuate fasciculus to the motor area and from there to the articulators of speech for vocalization x wernicke`s area the auditory area and speech understanding carl wernicke 1848­1905 german neurologist and psychiatrist he is known for his study of aphasia defects of expression or comprehension caused by brain disorders in the aphasic syndrome 1874 he described what later became known as sensory aphasia inability to understand the meaning of speech writing and other symbols wernicke s area speech comprehension in his research he discovered near the part of the cortex in the temporal lobe which receive auditory stimuli an area which was involved in the understanding of speech according to wernicke on hearing a word the sound of a word goes from the ear to the auditory area and then to wernicke`s area it is from the broca`s area that the vocalization of speech is activated reading -when a word is read the information goes from the eyes to the visual area of the cortex to the occipital lobe and sent to the areas proposed for the process of speaking reading writing and singing mainly located at or around sylvian and rolando fissures y neural pathways involved in the processing of spoken language speech production the basic structures of the utterance is thought to be generated in wernicke`s area and sent to broca`s area and then encoded.the programme is then passed to the motor areas which govern the articulatory organs © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development reading aloud the written form is first received by the visual cortex then transmitted to the angular gyrus to the wernicke`s area where it is thought to be associated with the auditory representation and then sent to the broca`s area o speech comprehension the signals arrive in the auditory cortex from the ear and are transferred to the wernicke`s area where they are interpreted z language areas of the brain the following areas which have been proposed for the processing of speaking listening reading writing and singing are mainly located around the sylvian and rolando fissures front parietal lobe is primarily involved in the processing of sensation and may be connected with speech and auditory area at a deeper level o fissure of rolando is mainly involved in motor functioning and is relevant to the study of speaking and writing o upper back of the temporal lobe plays a major part in the comprehension of speech wernicke s area o upper part temporal lobe is the main area involved in auditory reception known as heschl`s gyri -lower back frontal lobe is primarily involved in encoding of speech broca s area -back frontal lobe may be involved in the motor control of writing it is known as exner`s centre -left parietal region is involved with the control of manual signing -back occipital lobe is used for the processing of visual input 5.2 right hemisphere language abilities a typical language functions while the left hemisphere is involved in most language tasks recent evidence indicated that the right hemisphere too is involved in language processing © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development more precisely both hemispheres receive similar input and both attempt to process input for every language process the hemispheres compute information differently at each level of processing so that each hemisphere is most adept at handling particular inputs and producing particular outputs b word semantics the right hemisphere has been found to be more adept at processing single lexical items and the semantic relations between them while it is the left hemisphere that combines syntactic semantic and pragmatic information into a conceptual representation of a sentence understanding discourse and other minds there is increasing evidence that the right hemisphere is critical for understanding discourse thus the patient with right-hemisphere damage have impairment concerning narrative script interpretations inferential processing integration of information or conceptualization of the unit as a whole construction of new conceptual models and inferences about another person`s beliefs and intentions the right hemisphere has an ability to use knowledge of the world involved in scripting where a number of sentences are related to a topic patients who have damage in their right hemisphere show structuring problems in story recall and their speech is disrupted particularly at the level of discourse jumping from one topic to another incoherently c they experience difficulty in making inferences as well metaphor the coarse semantic coding of the right hemisphere may also relate to the ability of this hemisphere to understand metaphor when normal participants listen to natural language blood flow increases to both hemispheres however blood flow increases predominantly in the right hemisphere when participants are required to decide whether sentences contained plausible metaphors as compared to when they had to make decisions at the literal level © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development the right hemisphere can take over the left hemisphere functions -there is growing evidence that damage to language areas in the left hemisphere of young children is compensated for with the right hemisphere taking over the reacquisition of language this sometimes happens with adults as well while the extent of functional plasticity is not yet established it is clear that the right hemisphere is capable of taking over left hemisphere functions bilingual brain -central issues on neurolinguistic research about the bilingual brain whether different languages are represented in the different hemispheres of the brain if the age at which a second language is learned is related to lateralization is there hemispheric specialization for languages is the age at which a second language is learned related to lateralization studies showing right-hemisphere involvement o albert and obler 1978 karanth and rangamani 1988 and wuillemin richardson and lynch 1994 report greater involvement of the right hemisphere in bilinguals than in monolinguals o albert and obler 1978 argue that the right hemisphere plays a major role in the learning of a second language even in adulthood o their position is based partly on the finding that aphasia language dysfunction is more likely to be found following right-hemisphere lesions in bilinguals than monolinguals o if the right hemisphere is damaged and aphasia results they argue that the location of l2 must be in the right hemisphere studies finding no difference there are research reports that indicate that there is no difference in lateral dominance for the first and the second language © sistema universitario ana g méndez 2012 derechos reservados.

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tesl 553 language cognition and esl/curriculum development o soares1982,1984 walters and zatorre 1978 and zatorre 1989 found no difference between bilinguals and monolinguals o galloway and scarella 1982 in a spanish-english dichotic listening study found no evidence for the right hemisphere being involved more in the initial stages of informal adult,l2 second ­language acquisition o soares 1994 found no lateralization differences across the bilinguals or between bilingual and monolinguals o april and han 1980 and chary 1986 their studies of patients with aphasia reveal that there is no higher incidence for crossed aphasia o crossed aphasia concerns aphasia in right-handed patients resulting from righthemisphere brain damage o findings are not consistent o right-hemisphere difficulties are involved in many studies this suggests the distinct possibility that a l2 is sometimes located in the right hemisphere and sometimes not o there may be variables which determine hemispheric location but which have not been identified as yet does th age at which l2 is learned relate to lateralization o genesee hamers lambert mononen seitz and stark 1978 found that age at which a second language is learned affected lateral dominance they monitored the left and right hemisphere eeg electroencephalogram activity of adult bilinguals processing words the speakers were balanced bilinguals in the two languages they differed in histories of language acquisition o they studied three groups of adult bilinguals bilingual from infancy bilingual from around 4-6 years of age bilingual from adolescence o findings the left hemisphere was more involved than the right for the infancy and childhood bilinguals © sistema universitario ana g méndez 2012 derechos reservados.

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