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.

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

Language is a function ofthe human brain

Location

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

Evidence

Analgesics

PET Scans

Lesions / Strokes

ElectrophysiologicalTreatments (TranscranialStimulation)

Languge areas areLocated on Cortex

Language is ahigher cognitivefunction

Claim: Languge use andunderstanding has Modular Set up

Evidence

Experimental

Understanding ofsencences happensin three stages

1. Syntactic Analyses

2.Semantic Analyses

3. Integrattion

4. Extra Potential forextra cognitive Work ?

Evidence

ERP's of senctences that are dificult to process

LGA

N400

? 600

Lesions:

Brocas aphasia

Lesions in thisarea affec syntax but not nounds

Wernickes Aphasia

Lesions of this areaaffect nouns butnot syntax

Semantic Module

Syntactic Module

vs. Language of other specicies

Primates(i.e. vervet monkeys)

Lacking communicationabilites of human language

meanings can't be combined to form new meanings

Lacking Grammar

reduced number of meanings overall

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

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

Analyes of speech vs:other sounds

Analysis of Phonemesin higher auditory centresof the cortex

Which phonemesmake up words? which don't?

Cortical Areasspecialized for speechrecognition

2. Analysis of Meaning

Anaysis of Syntax (Roles: Doersactions and Objects

Analyis of words

Semantics

3. What aphasias can tell us

A.What are Aphasias

Aquired Languagedisorder leading to specific speech impaiments

Stroke

Brain Lesions

Wernickes Aphasia(After German Phyisologist KarlWernicke)

also called Fluent-Aphasia

Patients have ahard time describeingscenes and uttering meaningfulsentences in general

Syntax on the other handseems normal.

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

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

Believed to be tied toAnomia

Unability to namenouns in specificcategories like ...

Living things

Tools

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

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

Location Frontal CortexBordering with pariatal Cortex(Brodmans Areas ?)

B.Language is a function of the brain

Language has a fairly specific hemisphere (left)

Language areas can be located (fairly) specifically

Frontal

Temporal Lobe

However the location varies between people

C.Language seems to involve modules

Syntax Module

Roles clarified by sentence structure

Brocas Area

Semantics Module

Subtopic

Wernickes Area

Speech production vs. Speech understanding

Understand vs. Speak

Brocas Area

Connected to motor areas

Speek vs. Understand

Wernickes Area

4.What aphasiascan' tell us

A.General Problems of resolution

How do stages or modules inform each other

Purley Modular approach?

No influence from other modules exept for the output?

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)

Permanent Interation

One module informs the others

Time

Space

B.How is itaccomplishedon a neuronal level

If thats how it works in normal people?

- what role did plasticity play (newly wired?)

- small sample

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

damage not neat andnice

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)

Syntax Module

Able to extract rulesjust by listening

Evidence

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

The phonemic problem(how is the auditory analysisdone?)

We recognize words although the sounds may vary

Within speakers

Between speekers

Depending on the phoneme befor or after

no clear word boundaries

seperating speech from non-speech

The syntax problem

How do we determine what is bound to what

The sematic problem

Bank (money) vs. Bank (river)