LATERALITY AND LANGUAGE Flashcards
What should language not be confused with?
With communication
How did language evolve?
There appears to be no evolutionary intermediate to human language
Can non-humans species be taught to use language?
No species have same fine control of the lips, tongue and vocal cord as humans
- so its a problem
- instead studies use sign language
What was the experiment on washoe the chimp in 1960?
- trained to use sign language
- 3 years =-156.429 weeks 130 signs
- learned to combine them
But
- learning or gesturing?
- chimps language capacity of 2 year olds
Human study on language linking to brain?
Brocas’s aphasia
- french physician
- unable to speak more than few meaningless syllables for 21 years
- single lesions towards back of left frontal lobe = broca area
What happens when there’s damage to the Broca’s area?
- lacks intonation and inflection
- worst = total inability to produce speech
- anemia = difficult finding the right word
- speakers know what they are trying to sat and aware they re getting it wrong
What happens when you damage the left posterior, superior temporal gyrus?
Deficits in language comprehension
- wernicke’s area
- they can articulate quick and fluently but speech doesn’t have much meaning
- often unaware that they have a speech or comprehension deficit
What is the wernickes area know as?
- site of convergence of visual and auditory language information
- site of comprehension
- site of generation of verbal responses
- information passed to Broca’s area via arcuate fasciculus
What happens when patients have damage to the arcuate fasciculus?
- normal comprehension
- normal speech production
- difficulty in passing information
Where is the broca and wernickes area normally located?
In the left cortex
- 95% right handed people
- 75% left handed people
What side is language?
Left side
- comprehension of language
- speech
- disconnected left hemisphere can perform all language tasks normally
Whats the language abilities on the right side?
- emotional content of speech
- emotional resposponding
- some lexical ability - write names
- can make lexical decisions
Whats some symptoms of asymmetry?
- handedness
- eye dominance
What does fMRI do?
- measures blood flow to localised areas of the brain
- blood flow increases if brain area is more active
- which shows areas of high brain activity
What does the colours represent?
Red is less active
Yellow is more active
Where is the broca and wernickes area normally located in the cortex?
Left side
How does two cortical hemispheres communicate?
With each other through the corpus callosum - a large tract of neurons connecting the two sides
What are the two cortical hemispheres separated by?
Longitudinal fissures
Whats the treatment for severe epilespsy involving severing the corpus callosum called?
Split brain patients
Whats the study on split brain patients?
- word ball is presented in left visual field only
Subject is asked to say what it is and to select it from the objects behind the screen
What did the study on split brain show?
- unable to say what the object is
Only right visual cortex receives information from the left visual field - can pick out the ball with his left hand but not his right
- left hand knows what it is looking or but the right hand does not
What functions does left hemisphere have?
Logical, analytical
Computer like
Reductionists
What function does the right hemipshere have?
Synthesiser
Overal stimulus configuration
Wholistic
Emotional
What are some studies u can do to show the competition between hemispheres?
- block arranging tasks
- reading a book, held in the left hand
- unconscious actions of the right cortex
- hemispheres have different opinions - asked what fav occupation was
What does damage to right parietal lobe show?
Spatial awareness deficits
What did sperry state?
• The two cerebral hemispheres were effectively two separate brains
• Each possess their own conscious a
What did Eccles state?
• The right hemisphere is a non-conscious automaton, subservient to
the left hemisphere
• Left hemisphere has an interpreter that tries to bring things togethe
What are the two hemispheres of the cortex connected by?
The corpus callosum
Whats representational neglect?
• Lack of awareness of the left visual field : due to damage to right parietal cortex
• Does not occur with the right visual field after damage to the left visual cortex
