Language and the Language and the BrainBrain

Helena Helena GaoGao

Lecture 3 12 Oct., 2005Lecture 3 12 Oct., 2005

Lecture 3; Oct. 12, 2005

Required readings:Required readings: Gazzaniga, M., Ivry, R., & Mangun, G. Gazzaniga, M., Ivry, R., & Mangun, G.

(2001). (2001). Cognitive Neuroscience: The Cognitive Neuroscience: The Biology of the Mind. New York: W.W. Biology of the Mind. New York: W.W. Norton and Co. Chapter 9: Language and Norton and Co. Chapter 9: Language and the brain, pp. 351-399.the brain, pp. 351-399.

Vygotsky, L. (1996). Thought and Vygotsky, L. (1996). Thought and Language. Newly revised and edited by Language. Newly revised and edited by Alex Kozulin. The MIT Press. Chapter 4: Alex Kozulin. The MIT Press. Chapter 4: The Genetic Roots of Thought and Speech. The Genetic Roots of Thought and Speech. pp. 68-95.pp. 68-95.

Recommended readings:Recommended readings: Shapiro, K., & Caramazza, A. (2003). The Shapiro, K., & Caramazza, A. (2003). The

representation of grammatical categories in representation of grammatical categories in the brain. Trends in Cognitive Science, the brain. Trends in Cognitive Science, 7(5), 201-206.7(5), 201-206.

Brain areas involved in Language

Three major types of Three major types of AphasiaAphasia

Rosenzweig: Table 19.1, p. 615Rosenzweig: Table 19.1, p. 615 Borca’s aphasiaBorca’s aphasia

Nonfluent speechNonfluent speech Wernicke’s aphasiaWernicke’s aphasia

Fluent speech but unintelligibleFluent speech but unintelligible Global aphasiaGlobal aphasia

Total loss of languageTotal loss of languageOthersOthers: Conduction, Subcortical, : Conduction, Subcortical,

Transcortical Motor/Sensory (see also Transcortical Motor/Sensory (see also Kandel, Table 59-1)Kandel, Table 59-1)

Broca’s AphasiaBroca’s AphasiaBrodmann 44, 45Brodmann 44, 45

Lesions in the left inferior frontal region Lesions in the left inferior frontal region (Broca’s area)(Broca’s area)

Nonfluent, labored, and hesitant speechNonfluent, labored, and hesitant speech Most also lost the ability to name persons Most also lost the ability to name persons

or subjects (anomia)or subjects (anomia) Can utter automatic speech (“hello”)Can utter automatic speech (“hello”) Comprehension relatively intactComprehension relatively intact Most also have partial paralysis of one Most also have partial paralysis of one

side of the body (hemiplegia)side of the body (hemiplegia) If extensive, not much recovery over timeIf extensive, not much recovery over time

Wernicke’s Wernicke’s AphasiaAphasiaBrodmann 22, 30Brodmann 22, 30

Lesions in posterior of the left superior Lesions in posterior of the left superior temporal gyrus, extending to adjacent temporal gyrus, extending to adjacent parietal cortexparietal cortex

Fluent speechFluent speech But contains many paraphasiasBut contains many paraphasias

““girl”-“curl”, “bread”-“cake”girl”-“curl”, “bread”-“cake” Syntactical but empty sentencesSyntactical but empty sentences Cannot repeat words or sentencesCannot repeat words or sentences Unable to understand what they read or Unable to understand what they read or

hearhear Usually no partial paralysisUsually no partial paralysis

Sign LanguagesSign Languages Full-fledged languages, created by hearing- Full-fledged 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 Do not resemble the spoken language of the

same area (ASL resembles Bantu and Navaho)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)(gestures) Most gestures in ASL are with right-hand, Most gestures in ASL are with right-hand,

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

Signers with brain damage to similar Signers with brain damage to similar regions show aphasia as wellregions show aphasia as well

Spoken and Sign Spoken and Sign LanguagesLanguages

Neural mechanisms are similarNeural mechanisms are similar fMRI studies show similar fMRI studies show similar

activations for both hearing and deafactivations for both hearing and deaf But in signers, homologous But in signers, homologous

activation on the right hemisphere is activation on the right hemisphere is unanswered yetunanswered yet

DyslexiaDyslexia Problem in learning to readProblem in learning to read Common in boys and left-handedCommon in boys and left-handed High IQ, so related with language onlyHigh IQ, so related with language only Postmortem observation revealed Postmortem observation revealed

anomalies in the arrangement of cortical anomalies in the arrangement of cortical cellscells Micropolygyria: excessive cortical foldingMicropolygyria: excessive cortical folding Ectopias: nests of extra cells in unusual Ectopias: nests of extra cells in unusual

locationlocation Might have occurred in mid-gestation, Might have occurred in mid-gestation,

during cell migration periodduring cell migration period

Acquired Dyslexia = Acquired Dyslexia = AlexiaAlexia

Disorder in adulthood as a result of disease Disorder in adulthood as a result of disease or injuryor injury

Deep dyslexia (pays attn. to wholes):Deep dyslexia (pays attn. to wholes): ““cow” -> “horse”, cannot read abstract wordscow” -> “horse”, cannot read abstract words Fails to see small differences (do not read each Fails to see small differences (do not read each

letter)letter) Problems with nonsense wordsProblems with nonsense words

Surface dyslexia (pays attn. to details):Surface dyslexia (pays attn. to details): Nonsense words are fineNonsense words are fine

Suggests 2 different systems:Suggests 2 different systems: One focused on the meanings of whole wordsOne focused on the meanings of whole words The other on the sounds of wordsThe other on the sounds of words

Electrical StimulationElectrical Stimulation Penfield and Roberts (1959): During epilepsy Penfield and Roberts (1959): During epilepsy

surgery under local anesthesia to locate surgery under local anesthesia to locate cortical language areas, stimulation of: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

understand written questionsunderstand written questions

PET by Posner and PET by Posner and Raichle (1994)Raichle (1994)

Passive hearing of words activates:Passive hearing of words activates: Temporal lobesTemporal lobes

Repeating words activates:Repeating words activates: Both motor cortices, the supplemental motor Both motor cortices, the supplemental motor

cortex, portion of cerebellum, insular cortexcortex, portion of cerebellum, insular cortex While reading and repeating:While reading and repeating:

No activation in Broca’s areaNo activation in Broca’s area But if semantic association:But if semantic association:

All language areas including Broca’s areaAll language areas including Broca’s area Native speaker of Italian and English:Native speaker of Italian and English:

Slightly different regionsSlightly different regions Due to phonetic alphabet of Italian… Due to phonetic alphabet of Italian…

(“ghotia”)(“ghotia”)

PET by Damasio (1989)PET by Damasio (1989) Different areas of left hemisphere (other than Different areas of left hemisphere (other than

Broca’s and Wernicke’s regions) are used to Broca’s and Wernicke’s regions) are used to name (1) tools, (2) animals, and (3) personsname (1) tools, (2) animals, and (3) persons

Stroke studies support this claimStroke studies support this claim Three different regions in temporal lobe are Three different regions in temporal lobe are

usedused ERP studies support that word meaning are ERP studies support that word meaning are

on temporal lobe (may originate from on temporal lobe (may originate from Wernicke’s area):Wernicke’s area): ““the man started the car engine and stepped on the the man started the car engine and stepped on the

pancake”pancake” Takes longer to process if grammar is involvedTakes longer to process if grammar is involved

Williams SyndromeWilliams Syndrome Caused by the deletion of a dozen genes Caused by the deletion of a dozen genes

from one of the two chromosomes numbered from one of the two chromosomes numbered 77

Shows dissociation between language and Shows dissociation between language and intelligence, patients are: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 adulthoodin adulthood Guest speaker in the colloquium, Annette Guest speaker in the colloquium, Annette

Karmiloff-Smith, claims the otherwise:Karmiloff-Smith, claims the otherwise: Development alters the end result of the syndrome (?)Development alters the end result of the syndrome (?)

Lateralization of the Lateralization of the BrainBrain

Human body is asymmetrical: heart, Human body is asymmetrical: heart, liver, use of limbs, etc.liver, use of limbs, etc.

Functions of the brain become Functions of the brain become lateralizedlateralized

Each hemisphere specialized for Each hemisphere specialized for particular ways of workingparticular ways of working

Split-brain patients are good Split-brain patients are good examples of lateralization of language examples of lateralization of language functionsfunctions

Lateralization of Lateralization of functionsfunctions

(approximate)(approximate) Left-hemisphere:Left-hemisphere:

Sequential analysisSequential analysis AnalyticalAnalytical Problem solvingProblem 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

Emotional functionsEmotional functions Recognizing emotionsRecognizing emotions Expressing emotionsExpressing emotions

MusicMusic

Other studiesOther studies

Right ear advantage in dicothic listening:Right ear advantage in dicothic listening: Due to interhemispheric crossingDue to interhemispheric crossing

Words in left-hemisphere, Music in rightWords 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: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 basis for cerebral specialization for language and speechand speech

The Storage of Words and The Storage of Words and Concepts: The Mental Concepts: The Mental

LexiconLexicon 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 semantic information, syntactic information, and the details of word forms.details of word forms.

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

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

Other models distinguish between input and Other models distinguish between input and output lexiaoutput lexia The representation of orthographic and phonological The representation of orthographic and phonological

forms must be considered in any model.forms must be considered in any model.

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The mental lexicon is thought to be organized as information-specific networks – a model proposed by William Levelt in 1994

Support for the modelSupport for the model Semantic Priming StudiesSemantic Priming Studies Using a lexical decision taskUsing 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 making the lexicon decisions when the target is proceeded by a related prime (e.g., car is proceeded by a related prime (e.g., car truck) than a unrelated prime (e.g., whip truck) than a unrelated prime (e.g., whip truck).truck).

Expectancy-induced priming might occur if Expectancy-induced priming might occur if the time bet. The presentation of primes and the time bet. The presentation of primes and targets is long (e.g., > 500 msec) and the targets is long (e.g., > 500 msec) and the proportion of related word pairs are like car-proportion of related word pairs are like car-truck, cat-dog, etc.truck, cat-dog, etc.

The Nature of Conceptual The Nature of Conceptual or Semantic Representationor Semantic Representation Question: Question:

Is the same conceptual representation of a Is the same conceptual representation of a robin activated regardless of whether one robin activated regardless of whether one hears the word robin or sees one flying?hears the word robin or sees one flying?

A model proposed by Collins and Loftus A model proposed by Collins and Loftus (1975)(1975) Word meanings are represented in a Word meanings are represented in a

semantic network in which words, semantic network in which words, represented by conceptual nodes, are represented by conceptual nodes, are connected with each other.connected with each other.

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• Although this semantic network model (Collins & Loftus, 1975)has been extremely influential, 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 normal language comprehension and production.

Support from neurological Support from neurological evidence for the semantic network evidence for the semantic network ideaidea Different types of neurological problems Different types of neurological problems

create deficits in understanding and producing create deficits in understanding and producing the appropriate meaning of a word or concept. the 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 horsehorse 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 abilities are spared.abilities are spared.

Evidence from research done by E. Evidence from research done by E. Warrington (1970s-1980s)Warrington (1970s-1980s)

Findings: semantic problem can be Findings: semantic problem can be localized specifically to certain semantic localized specifically to certain semantic categories , such as animals versus categories , such as animals versus objects. objects.

E.g., patients who had great difficulties E.g., patients who had great difficulties pointing to pictures of food or living pointing to pictures of food or living things when presented with a word, things when presented with a word, whereas their performance with man-whereas their performance with man-made objects like tools was much made objects like tools was much better.better.

Evidence from H. Damasio and her Evidence from H. Damasio and her colleagues’ studies (1996)colleagues’ studies (1996)

Investigated a large population of patients with brain Investigated a large population of patients with brain lesionslesions

A naming task in three different conditions: (1) naming A naming task in three different 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, 7 patients demonstrated impairment in naming faces, 5 in naming animals; and 7 in naming tools. The 5 in naming animals; and 7 in naming tools. The remaining 11had a combination of problems in word remaining 11had a combination of problems in word retrieval for faces, animals, and tools, faces and retrieval for faces, animals, and tools, faces and animals, or animals and tools, but never for the animals, or animals and tools, but never for the combination of faces and tools together without also a combination of faces and tools together without also a deficit in animals.deficit in animals.

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Location of the brain lesions that are correlated with selective deficits in naming persons, animals,or, tools. (Damasio et al (1996)

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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) lobecorrelated with problems in naming animals

• Damage to the posterolaterol part of the left inferior temporal lobe, along with lateral temporo-occipito-parietal junction (IT+),was correlated with problems in retrieving the names of tools

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Three levels of Representation for Word Knowledge – predicated by cognitive models of wordProduction Based on Damasio et al’s Results (Caramazza, 1996)

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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 flow of info is bottom up, from Perceptual identification to “higher-level” word and lemma activation.

Interactive models of language Understanding would predict top-down influence to play a role as well.

Courtesy of Tamara Swaab. © 1997 by the Massachusetts Institute of Technology.

Spoken Input – lack of segmentation

Courtesy of Tamara Swaab. © 1997 by the Massachusetts Institute of Technology.

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Spectral properties vary according to sounds (Klatt, 1989)

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A model for letter recognition, the pandemonium model (Selfridge, 1959)

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A cohort model of British psychologistWilliam Marslen –Wilson (Marslen –Wilson & Tyler, 1980)

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

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Summary of lesions in the anterior superior temporal cortext that lead to deficits in Syntactic processing (Mazoyer et al, 1993)

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A study to test whether Lemma selection indeedPrecedes activation ofAppropriate lexeme (asIn Levelt’s model) by Van turennout (1999)

Method:Stimuli: words in Dutch ->Equ.: ERP

Proc.:Subjects were asked tomake a response onlywhen the words representingthe pic. Started with a “b’, and to withdraw theirresponse when the wordStarted with a “s”.