Language and the Brain

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Language and the

Brain

Helena

Gao

Lecture 3 12 Oct., 2005

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Lecture 3; Oct. 12, 2005

Required readings:



Gazzaniga, M., Ivry, R., & Mangun, G.

(2001).

Cognitive Neuroscience: The Biology

of the Mind. New York: W.W. Norton and

Co. Chapter 9: Language and the brain, pp.

351-399.



Vygotsky, L. (1996). Thought and Language.

Newly revised and edited by Alex Kozulin.

The MIT Press. Chapter 4: The Genetic

Roots of Thought and Speech. pp. 68-95.

the brain. Trends in Cognitive Science, 7(5),

201-206.

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Three major types of

Aphasia

Rosenzweig: Table 19.1, p. 615 Rosenzweig: Table 19.1, p. 615 

Borca’s aphasia



Nonfuent speech



Wernicke’s aphasia



Fluent speech but unintelligible



Global aphasia



Total loss of language

Others

: Conduction, Subcortical,

Transcortical Motor/Sensory (see also

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Broca’s Aphasia

Brodmann 44, 45 Brodmann 44, 45



Lesions in the left inferior frontal region

(Broca’s area)



Nonfuent, labored, and hesitant speech



Most also lost the ability to name persons

or subjects (anomia)



Can utter automatic speech (“hello”)



Comprehension relatively intact



Most also have partial paralysis of one

side of the body (hemiplegia)

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Wernicke’s

Aphasia

Brodmann 22, 30 Brodmann 22, 30



Lesions in posterior of the left superior

temporal gyrus, extending to adjacent

parietal cortex



Fluent speech



But contains many paraphasias

 ““girl”-“curl”, “bread”-“cake”girl”-“curl”, “bread”-“cake”



Syntactical but empty sentences



Cannot repeat words or sentences

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Sign Languages

 Full-fedged languages, created by hearing- Full-fedged languages, created by hearing-

impaired people (

impaired people (notnot by Linguists): by Linguists):

 Dialects, jokes, poems, etc.Dialects, jokes, poems, etc.

 Do not resemble the spoken language of the same Do not resemble the spoken language of the same

area (ASL resembles Bantu and Navaho)

 Pinker: Nicaraguan Sign LanguagePinker: Nicaraguan Sign Language

 Another evidence of the origins of language Another evidence of the origins of language

(gestures)

 Most gestures in ASL are with right-hand, or Most gestures in ASL are with right-hand, or

else both hands (left hemisphere dominance) else both hands (left hemisphere dominance)

 Signers with brain damage to similar regions Signers with brain damage to similar regions

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Spoken and Sign

Languages



Neural mechanisms are similar



fMRI studies show similar

activations for both hearing and deaf



But in signers, homologous

activation on the right hemisphere is

unanswered yet

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Dyslexia



Problem in learning to read



Common in boys and left-handed



High IQ, so related with language only



Postmortem observation revealed

anomalies in the arrangement of cortical

cells

 Micropolygyria: excessive cortical foldingMicropolygyria: excessive cortical folding

 Ectopias: nests of extra cells in unusual locationEctopias: nests of extra cells in unusual location



Might have occurred in mid-gestation,

during cell migration period

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Acquired Dyslexia =

Alexia



Disorder in adulthood as a result of disease

or injury



Deep dyslexia (pays attn. to wholes):

 “cow” -> “horse”, cannot read abstract words“cow” -> “horse”, cannot read abstract words  Fails to see small diferences (do not read each Fails to see small diferences (do not read each

letter) letter)

 Problems with nonsense wordsProblems with nonsense words



Surface dyslexia (pays attn. to details):

 Nonsense words are fneNonsense words are fne



Suggests 2 diferent systems:

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Electrical Stimulation



Penfeld and Roberts (1959): During epilepsy

surgery under local anesthesia to locate

cortical language areas, stimulation of:

 Large anterior zone:Large anterior zone:

 stops speechstops speech

 Both anterior and posterior temporoparietal Both anterior and posterior temporoparietal cortex:

cortex:

 misnaming, impaired imitation of wordsmisnaming, impaired imitation of words

 Broca’s area:Broca’s area:

 unable comprehend auditory and visual semantic unable comprehend auditory and visual semantic

material, material,

 inability to follow oral commands, point to objects, and inability to follow oral commands, point to objects, and

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PET by Posner and

Raichle (1994)



Passive hearing of words activates:

 Temporal lobesTemporal lobes



Repeating words activates:

 Both motor cortices, the supplemental motor Both motor cortices, the supplemental motor cortex, portion of cerebellum, insular cortex

cortex, portion of cerebellum, insular cortex



While reading and repeating:

 No activation in Broca’s areaNo activation in Broca’s area



But if semantic association:

 All language areas including Broca’s areaAll language areas including Broca’s area



Native speaker of Italian and English:

 Slightly diferent regionsSlightly diferent regions

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PET by Damasio (1989)

 Diferent areas of left hemisphere (other than Diferent areas of left hemisphere (other than

Broca’s and Wernicke’s regions) are used to

name (1) tools, (2) animals, and (3) persons

 Stroke studies support this claimStroke studies support this claim

 Three diferent regions in temporal lobe are Three diferent regions in temporal lobe are

used

 ERP studies support that word meaning are ERP studies support that word meaning are

on temporal lobe (may originate from

Wernicke’s area):

 ““the man started the car engine and stepped on the man started the car engine and stepped on

the pancake”

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Williams Syndrome

 Caused by the deletion of a dozen genes from Caused by the deletion of a dozen genes from

one of the two chromosomes numbered 7

 Shows dissociation between language and Shows dissociation between language and

intelligence, patients are:

 Fluent in languageFluent in language

 But cannot tie their shoe laces, draw images, etc.But cannot tie their shoe laces, draw images, etc.

 Developmental process is altered:Developmental process is altered:

 Number skills good at infancy, poor at adulthoodNumber skills good at infancy, poor at adulthood  Language skills poor at infancy, greatly improved Language skills poor at infancy, greatly improved

in adulthood

 Guest speaker in the colloquium, Annette Guest speaker in the colloquium, Annette

Karmilof-Smith, claims the otherwise:

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Lateralization of the

Brain



Human body is asymmetrical: heart,

liver, use of limbs, etc.



Functions of the brain become

lateralized



Each hemisphere specialized for

particular ways of working



Split-brain patients are good examples

of lateralization of language functions

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Lateralization of

functions

(approximate) (approximate)



Left-hemisphere:

 Sequential analysisSequential analysis

 AnalyticalAnalytical

 Problem solving_{Problem solving}

 LanguageLanguage

 Right-hemisphere:Right-hemisphere:

 Simultaneous analysisSimultaneous analysis  SyntheticSynthetic

 Visual-Spatial skillsVisual-Spatial skills  Cognitive mapsCognitive maps  Personal spacePersonal space  Facial recognitionFacial recognition  DrawingDrawing

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Other studies



Right ear advantage in dicothic listening:

 Due to interhemispheric crossingDue to interhemispheric crossing



Words in left-hemisphere, Music in right

 Supported by damage and imaging studiesSupported by damage and imaging studies  But perfect-pitch is still on the leftBut perfect-pitch is still on the left



Asymmetry in planum temporale:

 Musicians with perfect-pitch has 2x larger PTMusicians with perfect-pitch has 2x larger PT  Evident in newborns, thus suggesting innate Evident in newborns, thus suggesting innate

basis for cerebral specialization for language

and speech

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The Storage of Words and

Concepts: The Mental

Lexicon

 The Mental Lexicon: The Mental Lexicon:

 a mental store of information about word that includes a mental store of information about word that includes

semantic information, syntactic information, and the

details of word forms.

 Most psycholinguistic theories agree on the Most psycholinguistic theories agree on the central role for a mental lexicon in language

central role for a mental lexicon in language

 Some theories propose one mental lexison for both Some theories propose one mental lexison for both language comprehension and production

language comprehension and production

 Other models distinguish between input and Other models distinguish between input and output lexia

output lexia

 The representation of orthographic and phonological The representation of orthographic and phonological

forms must be considered in any model.

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W. W. Norton

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Support for the model

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Semantic Priming Studies



Using a lexical decision task

 Subjects are faster and more accurate at Subjects are faster and more accurate at

making the lexicon decisions when the target is

proceeded by a related prime (e.g., car truck)

than a unrelated prime (e.g., whip truck).

 Expectancy-induced priming might occur if the Expectancy-induced priming might occur if the

time bet. The presentation of primes and

targets is long (e.g., > 500 msec) and the

proportion of related word pairs are like

car-truck, cat-dog, etc.

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The Nature of Conceptual

or Semantic Representation



Question:



Is the same conceptual representation of a

robin activated regardless of whether one

hears the word robin or sees one fying?



A model proposed by Collins and Loftus

(1975)



Word meanings are represented in a

semantic network in which words,

represented by conceptual nodes, are

connected with each other.

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W. W. Norton

• Although this semantic network model (Collins & Loftus, 1975)has been extremely infuential,

it is a matter of debate how Word meanings are represented.

• No matter how they are represented, it is agreed that a mental store of word meanings is crucial to

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Support from neurological

evidence for the semantic network

idea

 Diferent types of neurological problems create Diferent types of neurological problems create

defcits in understanding and producing the defcits in understanding and producing the

appropriate meaning of a word or concept. appropriate meaning of a word or concept.

Patients with Wernicke’s aphasia makes errors Patients with Wernicke’s aphasia makes errors

in speech production that are known as in speech production that are known as

semantc-paraphasias (e.g., using the word semantc-paraphasias (e.g., using the word

horse

horse to mean to mean cowcow))

 Patients with progressive-semantic dementia Patients with progressive-semantic dementia

initially show impairments in the conceptual initially show impairments in the conceptual

system, while other mental and language system, while other mental and language

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Evidence from research done by E.

Warrington (1970s-1980s)



Findings: semantic problem can be

localized specifcally to certain semantic

categories , such as animals versus

objects.



E.g., patients who had great dificulties

pointing to pictures of food or living

things when presented with a word,

whereas their performance with

man-made objects like tools was much better.

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Evidence from H. Damasio and her

colleagues’ studies (1996)

 Investigated a large population of patients with brain Investigated a large population of patients with brain lesions

lesions

 A naming task in three diferent conditions: (1) naming A naming task in three diferent conditions: (1) naming famous faces, (2) naming animals, and (3) naming tools

famous faces, (2) naming animals, and (3) naming tools

 30 patients, 29 of whom had a lesion in the left 30 patients, 29 of whom had a lesion in the left hemisphere, showed impairments in this task.

hemisphere, showed impairments in this task.

 7 patients demonstrated impairment in naming faces, 5 7 patients demonstrated impairment in naming faces, 5 in naming animals; and 7 in naming tools. The remaining

in naming animals; and 7 in naming tools. The remaining

11had a combination of problems in word retrieval for

faces, animals, and tools, faces and animals, or animals

and tools, but never for the combination of faces and

tools together without also a defcit in animals.

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W. W. Norton

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W. W. Norton

Pet Scanning

• Brain damage in the left temporal pole (TP)

correlated with problems in

retrieving the names of persons

• Lesions in the anterior part of the Left inferior temporal (IT) lobe

correlated with problems in naming animals

• Damage to the posterolaterol part of the left inferior temporal lobe, along with lateral

temporo-occipito-parietal junction (IT+),

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Schematic representation of the components that are involved in spoken and written language

comprehension.

Input can enter via either auditory

(spoken word) or visual (written word) modalities.

The fow of info is bottom up, from Perceptual identifcation to

“higher-level” word and lemma activation.

Interactive models of language

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M cC le lla nd , J .L ., an d R um el ha rt, D .E . ( 19 86 ). Pa ra lle l D is tr ib ut ed P ro ce ss in g: E xp lo ra tio ns in th e M ic ro st ru ct ur e of C og ni tio n. V ol . 2 : Ps yc ho lo gi ca l a nd B io lo gi ca l M od el s. C am br id ge , M A : M IT P re ss .

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A cohort model of British psychologist William Marslen –Wilson

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M ün te , T .F ., Sc hi lz , K ., an d K ut as , M . ( 19 98 ). W he n te m po ra l t er m s b el ie c once pt ua l o rd er . Na tu re 3 95 :7 1-73

ERPs recorded in response to sentences that start with before (dashed lines) and after (solid lines) Munte et al (1998).

Task: “After/Before the scientist submitted the paper, the journal changed its policy”

Before are More

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A da pt ed fr om L ev el t, W .J. M ., Th e A rc hi te ct ur e of N or m al S po ke n La ng ua ge U se , i n B la nk en , G ., D itt m an , J., G rim m , H ., M ar sh al l, J.C ., an d W al le sh , C -W . ( Ed s.) , L in gu is tic D is or de rs a nd P at ho lo gi es : A n In te rn at io na l H an db oo k. B er lin : W al te r d e G ru yt er , 1 99 3

Speech Production

Outline of the theory of

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A da pt ed fr om v an T ur en no ut , M . H ag oo rt, P ., an d B ro w n, C .M . ( 19 99 ). B ra in a ct iv ity d ur in g sp ea ki ng : Fr om sy nt ax to p ho no lo gy in 4 0 m ill is ec on ds . S ci en ce , 2 80 , 5 72 -5 74 .

A study to test whether Lemma selection indeed Precedes activation of Appropriate lexeme (as In Levelt’s model) by Van turennout (1999)

Method:

Stimuli: words in Dutch -> Equ.: ERP

Proc.:

Subjects were asked to make a response only

when the words representing the pic. Started with a “b’, and to withdraw their