7 - Laterisation of Function Flashcards
What is the main concept of lateralisation of function?
The idea that the two different hemispheres of the brain have different specialisations.
Research has found that the left hemisphere is dominant for language whereas the right hemisphere is dominant for face recognition.
What is the name of the bundle of nerve fibres that connect the two hemispheres?
Corpus callosum
What are the advantages of lateralisation of function?
Increases neural processing capacity. Using one hemisphere to engage in a particular task leaves the other hemisphere free to engage in another function. It was found that lateralisation in chickens is associated with an ability to perform two tasks simultaneously (finding food and being vigilant for predators).
Architects and mathematically gifted people tend to have superior right hemispheric skills compared to their left hemispheric skills.
What are the disadvantages of lateralisation of function?
JW developed the capacity to speak out of right hemisphere, with the result that they could speak about information presented to the left or right hemisphere.
What are split brain patients?
Patients who underwent a form of surgery where surgeons have cut the corpus callosum in order to prevent the violent electrical activity caused by epileptic seizures crossing from one hemisphere to the other.
How did the surgery affect split brain patients?
Information from the left visual field goes into the right hemisphere, whereas information from the right visual field goes into the left hemisphere.
Because in split-brain patients the corpus callosum has been severed there is no way for the information presented to one hemisphere to travel to the other.
What tests can be performed on split brain patients and what will they find?
Patients are asked to stare at a dot on the centre of a screen and then information is presented in either the left or right visual field. They are then asked to make responses with either their left hand (right hemisphere), right hand (left hemisphere) or verbally (left hemisphere) without being able to see what their hands were doing.
They may be flashed an image of a dog in their right visual field and then asked what they have seen. They will be able to answer ‘dog’ because the information will have gone into their left hemisphere where the language centres are. If a picture of a cat is shown in their left visual field and they are asked what they have seen they will not be able to say because the information has gone into their right hemisphere, which has no language centres. However, they can draw a picture of a cat with their left hand because the right hemisphere controls this hand.
What are the disadvantages of split brain research?
The disconnection between the hemispheres is greater in some patients than in others, and some patients have drug therapy for their epilepsy for much longer than others, which may affect the way in which their brain works.
It is not valid to compare people who have had epilepsy with a control group who have no history of epileptic seizures.
Many studies on split-brain patients use as few as three participants, making it hard for results to be generalised.
In the real world a severed corpus callosum can be compensated for by the unrestricted use of both visual fields.
