Wernicke and Broca’s asphasia

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Describe Wernicke and Broca’s asphasia. To what extent has the study of these neuropsychological conditions contributed to our understanding of the biological basisof language?Hint: In order to answer this question effectively you should consider what the study of these conditions cannot tell us, as well as what it can.

What does biologicalbasis mean

4.What aphasiascan' tell us

The sematic problem

Bank (money) vs. Bank (river)

The syntax problem

How do we determine what is bound to what

The phonemic problem(how is the auditory analysisdone?)

seperating speech from non-speech

no clear word boundaries

We recognize words although the sounds may vary

Depending on the phoneme befor or after

Between speekers

Within speakers

C.Grammer is inborn?

"Chomksy": Languag is more likewatering a flower than learnig

Theory of language instinct:(language is no culturalphonmena - we need to be tought to read and writebut not to speak)

Babies don't need tobe tought to learn to speakcorrecly - they pick it up bylistening

Able to extract rulesjust by listening

B.How is itaccomplishedon a neuronal level

damage not neat andnice

The binding problem:how is a subject conntectedto an adjective (the green dog chases the cat)

If thats how it works in normal people?

- small sample

- what role did plasticity play (newly wired?)

A.General Problems of resolution

Space

Time

How do stages or modules inform each other

Permanent Interation

One module informs the others

Purley Modular approach?

Evidence

Experiments

"Bank": First priming thanmeaning inhibits other interpreations of "bank" (i.e.as river)

if it was totalinerconnection"bank" (river wouldhave never beenprimed in the firstplace)

No influence from other modules exept for the output?

3. What aphasias can tell us

C.Language seems to involve modules

Speech production vs. Speech understanding

Speek vs. Understand

Understand vs. Speak

Connected to motor areas

Semantics Module

Subtopic

Wernickes Area

Syntax Module

Roles clarified by sentence structure

Brocas Area

B.Language is a function of the brain

Language areas can be located (fairly) specifically

However the location varies between people

Temporal Lobe

Frontal

Language has a fairly specific hemisphere (left)

A.What are Aphasias

Brocas Aphasia(After french physiologist Paul Broca)

also called non-fluent Aphasia

Correct nounsare selected when talkingbut binding words (adverbs, verbs) and syntax is missing

Location Frontal CortexBordering with pariatal Cortex(Brodmans Areas ?)

Orignially thought tobe a problem with motorneurons / speech production,however it was found that syntax (roles)are guessed by the closest subject / objectsrather than understood

Wernickes Aphasia(After German Phyisologist KarlWernicke)

Believed to be tied toAnomia

Unability to namenouns in specificcategories like ...

Tools

Living things

Location: Parietal Cortex(Brodmans Area ?), borderof temporal Lobe

also called Fluent-Aphasia

Intitially thought of aproblem of understandingspeach but better explanined as an incapability of matchingphonemes to meaning

Syntax on the other handseems normal.

Patients have ahard time describeingscenes and uttering meaningfulsentences in general

Aquired Languagedisorder leading to specific speech impaiments

Brain Lesions

Stroke

2. What need to be accomphishedfor understanding language?Analysis of differnt kinds of Information

2. Analysis of Meaning

Analyis of words

Semantics

Anaysis of Syntax (Roles: Doersactions and Objects

1.Analysis of Auditory Information:Changes in Air -Pressure into neuronal signals creates the perception of "sound"

Analyes of speech vs:other sounds

Cortical Areasspecialized for speechrecognition

Analysis of Phonemesin higher auditory centresof the cortex

Which phonemesmake up words? which don't?

1.INTRODUCTIONExtent of languageuse and capabilitesbelieved to be uniqueto human specieas

vs. Language of other specicies

Primates(i.e. vervet monkeys)

Lacking communicationabilites of human language

reduced number of meanings overall

Lacking Grammar

meanings can't be combined to form new meanings

Language is a function ofthe human brain

Claim: Languge use andunderstanding has Modular Set up

Syntactic Module

Semantic Module

Lesions:

Wernickes Aphasia

Lesions of this areaaffect nouns butnot syntax

Brocas aphasia

Lesions in thisarea affec syntax but not nounds

Experimental

Understanding ofsencences happensin three stages

ERP's of senctences that are dificult to process

? 600

N400

LGA

4. Extra Potential forextra cognitive Work ?

3. Integrattion

2.Semantic Analyses

1. Syntactic Analyses

Location

Located in the left (communication)hemisphere (also for 60% of the)left handers

Languge areas areLocated on Cortex

Language is ahigher cognitivefunction

Evidence

ElectrophysiologicalTreatments (TranscranialStimulation)

Lesions / Strokes

PET Scans

Analgesics