introduction to cognitive neuropsychology & cognitive neuropsychology of language c81bio dr....

Introduction to Cognitive Neuropsychology &

Cognitive Neuropsychology of Language

C81BIO

Dr. Mark Haselgrove

Overview of the lecture

(1) Introduction to Cognitive Neuropsychology

What is it?

History: (i) Phrenology & Localization(ii) Recovery of function following damage

(3) Cognitive Neuropsychology of Language

Broca’s Area and Aphasia

Wernicke’s area and aphasia

(2) Mapping the brain

Brodmann’s map

(1) Introduction: What is Cognitive Neuropsychology?

- The study of the relationship between brain function and behaviour.

- Especially as determined through evidence from damaged brains, but can include other methods (e.g. imaging).

• Missile wounds (bullets)• Tumours (cancer)• Impact (road accidents)• Surgery (intractable epilepsy)• Disease (encephalitis,

hydrocephalus, HIV)• Strokes (blocks, bleeds)


- The study of the relationship between brain function and behaviour.

- Especially as determined through evidence from damaged brains, but can include other methods (e.g. imaging).

- Aims to assign particular psychological functions to particularbrain structures (if we accept modularity of brain function).

• Missile wounds (bullets)• Tumours (cancer)• Impact (road accidents)• Surgery (intractable epilepsy)• Disease (encephalitis,

hydrocephalus, HIV)• Strokes (blocks, bleeds)

• Assumption: brain function is “localised” or “modular”, with different structures performing different roles.

• Many functions rely on distributed brain systems.

– Language, memory etc. use much of the brain.

– Brain regions are specialized to perform particular roles, but these may not map neatly onto our ideas of “brain functions”.


CAUTION!

(1) Introduction: History

- Franz Joseph Gall (1758-1828).- Johan Spurzheim (1776-1832)

- As a youth, Gall was annoyed by students with a good memory but poor original thinking…

- Recalled these students had large protruding eyes

Developed a theory of brain function:Localisation of function:

Different parts of the brain responsiblefor variations in individual differences


Phrenology

- People who had skills in maths, music, sense of colour combativeness, - bumps in other areas

- Depressions in skull indicate underdevelopment- Amativeness (sex drive) behind lower part of ears

Variety of people with different extreme traits examined:

Murderers (N=25)SadistsTorturers

Considered evidence from paintings and busts


- Used as a method of personality assessment: Cranioscopy

- The fall and ……collapse of Phrenology

- Invited quackery, and ridicule by association- Most assessments entirely subjective

- Outside of the skull does not mirror even the inside of the skull, let alone the underlying brain

Pierre Flourens (1794-1867)

“The famous physiologist, Magendie, preserved the brain of Laplace. Spurzheim had the very natural wish to see the brain of the great man. To test the scienceof the phrenologist, Mr Magendie showed him, instead of the brain of Laplace,that of an imbecile. Spurzheim, who had already worked-up his enthusiasm,admired the brain of the imbecile as he would have admired that of Laplace”


Flourens also conducted experiments…

Lesioned parts of the cortex of different animals: Observed how it behaved

At first: → Moved very little, refused to eat and drink

Later: → Recovery of function. To the point of appearing normal.

Pattern of loss and recovery seemed inconsistent with the assumption of localisation

However:

Lesions to: Parts of the brain stem → permanent breathing difficultiesCerebellum → loss of locomotor co-ordination (not sex drive!)

(2) Mapping the brain

- Brodmann’s Areas (BAs, 1909)

- Appearance of cortex under microscope (cytoarchitectonics)

- Should BAs map neatly onto psychological functions? - Partly, because cytoarchitectonic structure is influenced by connections.


Launched the field of Neuropsychology

Jean Baptiste Bouilaud (1796-1881)

Proposed that certain functions were localised

Physicians noted that damage to left hemisphere → impaired movement on right

Writing also disrupted…Language on the left?

Paul Broca (1824-1880)

Received a patient Monsieur “Tan” LeborgneCould only say “Tan” and utter an oath

Bouilaud’s son in law, Ernest Auburtin, reported a case of a patient who lost theability to speak when pressure was applied to the exposed frontal lobes


Tan died in 1861

Autopsy revealed a lesion to the left frontal lobe:

Thus demonstrating: LateralizationLocalization

Anterior speech region = Broca’s area

Syndrome that results = Broca’s Aphasiafrom damage to this area


Carl Wernicke (1848-1904)

Investigated region of the cortex that receivesinformation from the ear. Behind Broca’s area

Wenicke’s patients:

- Spoke fluently, but with no sense- Could hear, but could not understand what was said

to them

This region of temporal lobe = Wernicke’s’s area

Syndrome that results = Wernicke’s Aphasiafrom damage to this area


Model of Language processing

Auditory information sent to:

(1) Wernicke’s area (Sounds → sound

images)

(2) Sound images transmitted along Arcuate fasciculus to:

(3) Broca’s area (representation of speech movements)

From here instructions sent to control mouthmuscles…..

Conduction aphasia:Consequent upon Arcuate fibres being damaged:

Comprehension maintained…and speech sounds

Speech impaired (difficulty repeating what is said to them)

Reading

Kolb, B., & Wishaw, I. Q. (2003). Fundamentals of Human Neuropsychology,Worth Publishers. Ch’s 1, 3 & 17.

Next Time: The Neuropsychology of Memory and Vision (1st May noon)

Email: [email protected]

introduction to cognitive neuropsychology & cognitive neuropsychology of language c81bio dr....

Documents

brain of laplace

brain responsible

brain regions

brain brodmanns map

theory of brain function

modularity of brain

ideas of brain functions

particular brain structures