Biological - Localisation (Experiments) Flashcards
Broca Aim
Case study on parts of brain responsible for language.
Broca context
Loui Leborne lost ability to speak at 30.
Could only pronounce Tan.
Accompanied with hand gestures.
Intact intelligence, no speech articulation.
Results - Brocha
An autopsy showed a lesion in the area of the frontal lobe leading to Broca’s area.
Brocha - Evaluation
Naturally occuring lesions are not neatly confined to specific areas.
You have to wait until the patient dies.
Lashley Aim
effect of induced brain damage on behavior
Lashley Method
○ Lashley would teach rats to run through a maze with a reward incentive of food.
○ After learning occurred he would remove an area from the cortex and register the change in behavior when the rat ran the maze again.
He did by removing varying portions of the cortex in the rat brains.
Lashley results
○ Memory was distributed rather than localized since there was no localized place for remembering the route in a maze.
○ The principle of mass action - As more cortex is destroyed then performance also beings to hinder and deteriorate.
Define Equipotneitality
The ability of one part of the cortex to take over functions of another part of the cortex
Gazzaniga (1967) Aims
To test the theory of lateralization and to see if two hemispheres have unique functions.
Gazzaniga (1967) method
Gazzaniga set up an experiment where to screens would be shown to different eyes which corresponded to the two hemispheres of the brain.
When shown a picture of a spoon in the left visual field and asked to name or describe the patients said nothing. When asked to pick a corresponding object from a group of objects behind the screen they felt around and picked a spoon with their left hand which visually and physically correspond to the right hemisphere. The right hemisphere saw the spoon and picked it with the left hand but the center of speech is in the left hemisphere so the patients were unable to explain what they saw and what they did.
Gazzaniga 1967 Results
When the word pencil was flashed then the patients also chose a pencil hence indicating that the right hemisphere can comprehend language and insinuating that language production is lateralized to the left hemisphere.
Thu supporting lateralization of language in the left hemisphere.
The four findings listed above demonstrate the dominance of the left hemisphere for language. The left hemisphere produces speech and makes a person consciously aware of something. However, this lateralization is not strict: some forms of language production and comprehension can be performed by the right hemisphere also. Moreover, it differs somewhat from person to person.
