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7/31/2019 Language&The Brain
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LANGUAGE
&THE BRAIN
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Why do we have preferences????
Which foot did you use?
Which hand did you use?
Which side of your head did you turn?
NOW!
Imagine you do those activities with opposite
side of your preference!
So, the answer lies in the brain, its
structure and function.
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The Hemispheres of the Brain
Frontal lobes
Median longitudinalfissure
Central sulcus (fissure ofRolando)
Pariental lobes
Occipital lobes
The over head view
LEFT CEREBRALHEMISPHERE
RIGHT CEREBRALHEMISPHERE
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The side view
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Size and the Weight of the Brain
The brain of average human adult
1-1,5Kg.
The size of the brain does not relate tothe intelligent of people.
Adult brain weight approximatelythree times the weight of his brain at
birth.
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The Central Nervous System of Cerebral Cortex
Four major parts of the brain;
1. The Medulla Oblongata (sumsum sambung) concerned
2. The pons varolii (Jembatan Varol) physical
3. Cerebellum (Otak Kecil) body
4. Cerebral Cortex / Cerebrum (Otak besar) function
The Brain &Spinal Cord
The central nervoussystem
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The medulla oblongata, thepons varolii, and the
cerebellum
PhysicalBodily
Function
Breathing, heartbeat, transmission andcoordination of movement, involuntary
reflexes, digestion, and emotional
arousal
The Cerebral Cortex
Advance intelectual
functioning and language
Thinking, reasoning, learning,memory, intelligence, senseof responsibility, perceptionof the senses, initiation andcontrol of voluntary musclecontraction
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The Brain
pons varolii
medulla oblongata
cerebellum
spinal cord
cerebral cortex
cerebrum
Acknowledgement: Picture of model from Mentone Educational Centre C15
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HEMISPHERIC STRUCTURE AND
FUNCTION
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Left and right hemispheres control
opposite sides of the body.e.g:
Stroke is the sudden death of brain cells
due to lack of oxygen, caused byblockage of blood flow or rupture of anartery to the brain.
A stroke in the right hemisphere of braincan affect victims on the left side of thebody and the opposite.
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Vision
A stroke in one side of the brain will not
automatically cause useless the eye andear on the opposite side of the body.
The person will still be able to see a
whole image from only the right eye,since both the left and the righthemisphere will be involved.
The divided fields of vision allow fordirect sensory input to both hemisphereseven with only one functioning eye.
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Audition
Certain types of sounds tend to be processedin one hemisphere while other types tend to
be processed in the other hemisphere.
The hemisphere closest to the damaged ear
will still be able to receive sound, since theundamaged ear will send sounds signalsinternally to its opposite hemisphere.
Having only one functioning ear still enables
hemisphere to access the sound. It becausethe other good ear can extend sounds to bothhemisphere.
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Hemispheric Dominance
The Left Hemisphere Dominates theRight
Dominance is where the onehemisphere is controlling the one.
Hand and Foot Preference
A left hemisphere dominant person wouldtend to use the right hand and the right foot
and the opposites.
The majority of people prefer their righthand and foot. It indicates that the left
hemisphere dominates the right.
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Left- Handers
The lack of strong dominance for left-
handers is believed to be a factorcontributing to speech disorders and tovarious reading and writing dysfunction(stuttering and dyslexia).
Lamm and Epstein (1999), report that left-handers native Hebrew speakers perform lesswell than right-handers in the study of English,
Especially reading. It seems to be caused by thetwo hemispheres vying with one another fordominance and Salive, Guralnik, and Glynn,(1993) argue that left- hander dies younger.
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A gene for handedness
The researcher who has studiedhandedness and believe there is a specificgenes for it is Amar Klar.
He convinced that there was a single gene
that makes us right handed. When thegene was defective, we have a 50%chance of being right handed and 50%chance of being left handed or
ambidextrous.
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Left-handers:Achievement and discrimination
Interestingly, among left-handers there isa greater proportion, artists, musiciansand writers that is found among right-handers. In the 20th century USpresidents are left-handers such asTruman, Reagan, Bush, and Clinton.
The greatest thinker of all time, AlbertEinstein. He is a left handed too.
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Sound Preferences
The two hemispheres specialize inprocessing these two types of sounds(speech and non-speech).
For the true right hander, speechsounds are mainly processed in the lefthemisphere while music, animal soundand noises are mainly processed in theright hemisphere. The opposite will bethe case for some left hander.
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Listening behind a closed door
If you are right hander right earforward.
This is because :
Speech sounds are processed inthe left hemisphere.
The first big impulse of speechsound will be transmitted to the left
hemisphere to the right ear The first big impulse will precede
and dominate any other bigimpulse.
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Lateralized Hemispheric Function
Lateralization is the separation offunction of brain hemispheres
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Left-Hemisphere Specialization
Left-hemisphere is concerned withlogical and analytical operations andhigher mathematics.
The main language centres are BrocasArea, in front part of the brain,Wernickes Area, Towards the back,and the Angular Gyrus, which is even
further back.
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Right-Hemisphere Specializations
The right hemisphere is involved inrecognizing emotions, recognizingfaces, and perceiving the structuresof things globally without analysis.
It also deals with music and nonlinguistic sounds, such us noises andanimal sounds.
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Sex Differences and Lateralization
It may be that females have a thickerleft hemisphere while the males have athicker right hemisphere.
Language ability typically are locatedin the left hemisphere and visual-spatial are located in the righthemisphere.
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Split Brain Effects
The certain aspects of lateralizationhave been confirmed by the work of
Sperry (1982) separated the twohemispheres of the brain by severingthe connecting tissue, the corpus
callosum, of a number of patients.
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It was found that the split-brain personcould still use speech and writing in thedisconnected left hemisphere but thattheir right hemisphere had little such
capacity. In normal persons, the righthemisphere has some capability.
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Language Areas and their
Functions
Brocas Area, The Motor area, andSpeech Production
The speech production process wouldbegin in Brocas Area, pass on throughthe arcuate fasciculus to the motor area
and from there to the articulators ofspeech for vocalization.
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Wernickes Area, the auditory area,
ans speech understanding
Speech comprehension
It is located in the upper part oftemporal lobe, extending upwards intothe partial lobe, plays a major part inthe speech comprehension.
Wernickes area, must in some way be
connected to the auditory area.
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Speech Production
The basic structure of the utterance is thought to be
generated in Wernickes area and is sent to Brocas
area for encoding, and then passed on to adjacent
motor area, which governs the articulatory organs.
Reading aloudThe written form is received by visual cortext, then
trasmitted via angular gyrus to Wernickes area, where
it is ought to be assosiated with the auditory
representation, then the utterance structure is then
sent on to Brocas area.
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Right-Hemisphere LanguageAbilities
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Typical Language Function
Recent evidence indicates that the righthemisphere is involved in languageprocessing as well.
Left+Right hemispheres receive similiar
input and both attempt to process for everylanguage process.
The hemispheres compute informationdifferently at each level of processing (e.g.
Semantic processing), so that eachhemisphere is most adept at handlingparticular inputs and producing particularoutputs (Chiarello & Beeman, 1998, p. X)
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Word semantic
(Faust, 1998)
The right hemisphere has been found to
be more adept at processing single lexicalitem and the semantic relation between them.
While it is the left hemisphere that combine
syntactic, semantic, and pragmatic information
into a conceptual representation of a
sentence.
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Understanding Discourse and other minds
The RH is critical for understandingdiscourse. (Beeman,1993)
E.g:
Patients who have damage in their RH showstructuring problems in story recall (Moya etal 1986), and their speech disrupted,particularly in the level of discourse,jumping from one topic to anotherincoherently. (Brownell&Martino1998) Theyexperience difficulty in making inference as
well.
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Metaphor
The coarse semantic coding of the RHmay also relate to the ability of thishemisphere to understand metaphore(Brownell, 1988)
E.g: The king of the Jungle went to the
palace.
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The Right Hemisphere Can Take
Over Left-Hemisphere Functions.
There is growing evidence that damageto language areas in the left hemisphere
of young childern is compensated for,with the right hemisphere taking over thereacquisition of language.
This sometimes happens with adults, aswell.
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See, the example p. 326-327
Smith & Sugar (1975) report a boy aged 5
years and 6 months who had a left
hemispherectomy (the removal of the entire
LH, which includes the main language
areas). When tested 21 years later, heshowed normal language and intellectual
capacities.
The RH and other intact residual structuresmust therefore have compensated for the
loss of the hemisphere.
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So,,,
The right hemisphere is often capable oftaking over typical left hemisphere
functions, even after the entire lefthemisphere has been removed.
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The Bilingual Brain
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Is there Hemisperic Specialization forLanguages?
Does the Age at which a SecondLanguage is Learned Related to
Lateralization?
Consider these questions!
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Is there Hemisperic Specializationfor Languages?
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Albert and Obler (1978) argue that theright hemisphere plays a major role in thelearning of a second language even inadulthood.
Their position is based partly on the findingthat apashia (language dysfunction) is
more likely to be found following right-hemisphere leions in bilinguals (10%) thanin monolinguals (1-2%).
Study showing right-hemisphere
involvement
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If the right hemisphere is damaged, andapashia results, then they argue that the
location of second language must be inthe right hemisphere.
Cont...
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A number of studies, on the otherhand, have reported no different in lateraldominance for the first and the secondlanguage.
Soares (1982, 1984), Walters andZatorre (1978), and Zatorre (1989) foundno different between monolinguals andbilinguals.
Studies Finding No Different
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Galloway and Scarcella (1982), in aSpanish-English dichotic listening study,
found no evidence for the righthemisphere being involved more in theinitial stages of informal, adult, second-
language acquisition.
Cont...
S
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While finding are not consistent, the fact thatthe right-hemisphere difficulties are involved
in so many studies suggests the distinct
possibility that a second language sometimes
locates in the right-hemisphere and sometimes
not. There may be variables which determine
hemispheric location but which have not been
identified yet.
So...
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Does the Age of at which a Second
Language is Learned Related toLateralization?
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Genesee, Hamers, Lambert, Mononen,
Seitz, and Stark (1978) found that the age at
which a second language is learned affectedlateral dominance.
E.g:
1. Those who became bilingual from infancy.
2. Those who became bilingual from around
4 to 6 years of age.
3. Those who became bilingual from
adolescence.
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Sussman, Franklin, and Simon (1982)
showed that early bilinguals (acquired prior
age 6) showed that LH dominance for bothlanguages, while late bilinguals (acquired
after age 6) revealed LH dominance only
for the first language and symmetricalhemisphere involvement for the second
language.
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Wulleim (1994) reported greater RH
involvement for older learners of both
English and Tok Pidgin than for younger
learners. Older learners were those who
acquired the languages after the age of 8
years.
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However, Vaid (1987) reports the opposite
for French-English bilinguals, the LH was
more affected in late bilinguals (acquired
second language between age of 10 and 14)
than in early bilinguals (acquired second
language before age of 4)
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Gordon and Zattore (1981) found no
difference in hemisphere dominance
between two groups of English-Spanish
bilinguals, with one group having acquired
the second language around the age of 9 and
another having acquired it around the age of
13.
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Klein, Zattore, Milner, Meyer and Evans
(1994) have reported similar findings. Theyused PET (Positron Emission Tomography)
to compare cerebral blood flow when
English-French bilinguals repeated words inthe first (English) or in the second language
(French), with the second language being
learned after the age of 5 years. There wasrelatively little difference, with the two
languages activating similar brain areas.
S
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The distribution of speech areas in the brain
appears to be related to a variety of factors,
including, for example, what task bilinguals
are given (comprehension vs. production),
when a second language is acquired, and
what method of analysis is used.
So,
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Sign Language
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Hemisphere location of Sign Language
Comparisons of Sentence Processingbetween Signers and Non-Signers
We will study about these;
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Left-Hemisphere Damage Affects Signing
Right-handed deaf signers, exhibit apashia
when critical LH areas are damaged
(Poizner, Klima, & Bellugi 1989).
Hemispheric Location of Sign
Language
Tachistoscopic Studies Inconclusive
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Tachistoscopic Studies Inconclusive
Most of the research involved in determiningthe hemispheric location of sign language is
based largely upon tachistoscopic visual half-
field studied, where what enters the right and the
left field of each eye is controlled by a devicecalled a tachistoscope, which projects images.
As a whole, these studies yield inconsistent
and contradictory findings, ranging from reportsof right hemisphere dominance, left-hemisphere
dominance, to no hemispheric asymmetries for
sign-language processing in the deaf.
C t
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Poizner, Battison, and Lane (1979)
compared the contribution of movement in
sign-language stimuli. They reported a leftvisual field (LVF) advantage for static signs
and no hemispheric asymmetry for moving
signs.
Cont...
Cont
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Grossi, Semenza, Corazza and Volterra
(1996) reported no hemisphere asymmetryfor judgements of signs based o psysical
characteristics.
However, a significant right visual field
(RVF) advantage emerged when subjects
were asked to make judgements ofhandshapes that were matched in shape to
one another.
Cont...
Comparisons of Sentence
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A fMRI study by Neville, Bavelier, Corina,
Rauschecker, Karni, Lalwani, Braun, Clark,Jezzard and Turner (1998) shows that when
hearing or deaf subjects process their native
languages (ASL or English), anterior andposterior languages areas within the left
hemisphere are used.
Comparisons of Sentence
Processing between Signers and Non
Signers
C t
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Other electrophysiological (EEG, etc)studies of neurologically intact native
signers also indicate that both the left and
right hemisphere are active during ASLsentence processing (Neville, Coffey,
Lawson, Fischer, Emmorey, and Bellugy,
1997).
Cont...
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The left hemisphere appears to be centrally
involved in sign language, as it is with non-
signers. The right hemisphere also isintricately involved but in ways different
from that of non-signers.
In conclusion...
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Language Disorders
Aphasias
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Aphasias
Damage of specific site in the hemispherewhere language is located
The damage influences :a. Speech
b. Reading
c. Writing
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1. Brocas Aphasia
it caused by war injuries, strokes, caraccidents
The damage is only to certain portionof brain
It influences speech and writing
Meaningful but shortened speech eg:ungrammatically correct
Which one is easier?
The book that the irl is takin is blue
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Syntactic relation
Is the cause
Same word utter in conversation could be
more difficult than when they use itwhile they are singing.
Example???
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2. Wernickes Aphasia
Non-sense speech = Double talk
Sounds right, grammatically correct
BUT meaningless Example ???
Beside that, it also includes similar
sound (Chair-Shair), word loss (it isa.)
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Other Speech Related Aphasias
1. Pure word deafness cannot recognizethe sounds of words as speech but canhear other types of sounds (ex:song).
2. Conduction aphasia poor ability torepeat words.
Example : bubble bupple, noun verb,
64928 John is sleeping
3. Anomic Aphasia Problems in findingthe proper words.
Exam le : Geor e men ambil ba u utih
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4. Apraxia unable to respond verbalcommand
5. Global Aphasia many or all aspect oflanguage are severely affected especiallyin the left hemisphere (language areas) ex
: stroke
Determining type of Aphasia
a. Was the tissue completely destroyed or
damage slight?
b. Did the damage occur suddenly orovertime?
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Dyslexias (Reading and Writing)
Some children only able to writebackwards (reed-deer), confuse letters
(b-d, p-q) So, better if we give words in context ,
not in isolation
Types :a. Alexia reading (ex: cannot read
what they have written)
b. Agraphia writing (ex: they can say
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Japanese writing aphasias
It displays quite unusual characteristicsdue to the nature of their complex
writing system Syllabic kana
Morpheme kanji
Some patients cannot read kana butthey can read kanji.
R l ti ifi t f
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Relating specific aspects of
language toCertain localized
areas of thebrain
LOCALISM
Global areas of
the brain
HOLISM
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Effects
Attention span
Motivation
Start to do something but suddenlycancel it
Want to say something but suddenly
forget itBesides that
People who have language disorder
DOESNT MEAN the have lan ua e
Sign-Language Aphasia
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Sign-Language Aphasia
Left hemisphere language area signand signing system
1. Brocas aphasia with signers
Example : native of signer American SignLanguage got stroke to the lefthemisphere will accurate in making asingle sign of language which simple
uninflected meaning BUT they unable toproduce correct movement
2. Wernickes aphasia with signers
produces meaningless individual words
M th d f I ti ti B i
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Methods of Investigating Brain
and Language
1. Traditional
a. Post-Mortemused by Broca, examine
the patients who had displayedlanguage disorders
b. Brain-Operation, accident or tumour
cause removal of a lobe of the brainand entire hemisphere
c. Electrical stimulation, patients who are
conscious during brain surgery.
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2. High-Tech Methods (observe the actualfunctioning of the brain in real time,
without surgery)
a. The CAT (Computerized AxialTomography) scan. X-ray to construct
three dimensional image of the wholebrain or a portion of it
b. The PET (Positron Emission
Tomography) scan. Injecting a mildlyradioactive substance into the blood anddetectors surround the persons head.
When blood flow increases, the brain
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c. Magnetic and Functional MagneticResonance Imaging (MRI, fMRI). Measure
brain function by taking advantage of theincreased local blood flow in areas of thebrain that are active. When the brain
performs a specific cognitive task, there isan increase in blood flow and the cellularactivity associated with that task.
d. Event-Related Potentials (ERPs) =evoked potentials. Measure voltagechanges in the brains by