Localisation vs Holism Flashcards
Outline Lashley’s study from 1950.
(Supports the holistic brain theory)
Supports the holistic brain theory.
This is because when they removed areas of the cortex (between 10% and 50%) in rats brains; the rats were learning to run a maze - he did not find a specific area involved in learning but concluded that it appeared to occur all over the brain.
He concluded that complex cognitive tasks are supported by the holistic theory of brain function.
However, this may be difficult to apply to humans, as human brain structure differs from a rats.
Outline Fink and Halligan et al’s study from 1996.
(Supports the idea that the left hemisphere is localised to detail)
Supports the idea that the left hemisphere is localised to detail.
This is because they found that when you ask somebody to look at a picture and to identify the small detail there will be a greater level of activity in the left hemisphere than if they look at the picture holistically which prompts more activity in the right hemisphere.
This suggests the left hemisphere codes for detail, and the right hemisphere codes for holistic differences.
What does the right hemisphere lateralise for?
Recognising emotions.
Spatial relationships.
Overall pattern differences.
Outline Heller and Levy’s study from 1981.
Supports the idea that the right hemisphere is lateralised for recognising emotions.
This is because they found that if a photo has a face that has been split so one half is smiling and the other is neutral, the emotion displayed in the left-hand side of the picture is the emotion recognised by the participant more quickly.
This suggests that the resources for spatial relationships are found within the right hemisphere.
What did Narumoto et al state in 2001?
Stated that the right hemisphere is dominant in recognising emotions in others.
Outline Petersen’s study from 1988.
(Supports the localised functioning of Wernicke’s and Broca’s areas)
Supports the localised functioning of Wernicke’s and Broca’s areas.
This is because they demonstrated that Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.
This suggests these areas of the brain have different functions.
Outline Tulving et al’s study from 1994.
(Supports the idea of localised memory functions)
Supports the idea of localised memory functions.
This is because they found semantic and episodic memories reside in different parts of the prefrontal cortex.
This suggests that brain memory is localised to specific regions.
What is a commissurotomy? When is it used?
The severing of the corpus callosum.
Used to treat those who suffer from epilepsy, and are not helped by drug treatment.
Surgeons cut the corpus callosum so that epilepsy is kept in one half of the brain or even removed one hemisphere completely.
Does a commissurotomy treat everyone with epilepsy? Why?
No, as in a small number of people with drug resistant epilepsy, there is more than one area, so more parts of the brain may need removing.
Outline the case study of Cameron Mott.
(Child with a right hemispherectomy)
At three, Mott contracted a rare and lethal brain disorder known as Rasmussen’s Encephalitis.
It destroyed her right hemisphere, and by the time she was six years of age, she was experiencing epileptic fits within minutes of waking.
Medication did not effectively treat her, and she spent many years wearing a protective helmet; personality changed from a bubbly toddler to a child who was flat and tired; her ability to learn declined.
After the hemispherectomy surgery Mott was partially paralysed on the left side of her body, as the contralateral structure of the brain meant the right hemisphere controlled her left.
Over the following weeks Mott participated in intensive post-surgery rehabilitation, and 6 weeks later she walked out of the hospital with half her brain.
Mott’s left hemisphere, being so plastic due to her age, was able to compensate for the loss of her right hemisphere.
The cavity in which the right hemisphere originally was filled with cerebral-spinal fluid in order to support her now single-hemisphere brain.
What is a hemispherectomy?
A surgical procedure where the diseased half of the brain is completely removed.
What is neurosurgery also referred to as?
Psychosurgery.
What is the cingulate gyrus?
An arch-shaped convolution situated just above the corpus callosum.
Problems in the cingulate gyrus often lead to an inability to let go of a thought.
What is the cingulotomy?
A neuro-surgical procedure that involves lesioning the cingulate gyrus.
Outline Dougherty et al’s study from 2002.
(Supports a holistic explanation of brain behaviour)
Supports a holistic explanation of brain behaviour.
This is because they studied 44 OCD patients who had undergone a cingulotomy, finding that at 32 weeks, 1/3 had met the criteria for successful response to surgery, and 14% for partial response.
The success of procedures like this strongly suggest that symptoms and behaviours associated with serious mental disorders are localised.
However, for 2/3 of the PPs, it wasn’t successful. Only the minority responded positively. This suggests that there may be other areas involved in OCD.
