Localisation Of Fucntion In The Brain Flashcards
What is the concept of localisation of function in the brain?
The idea that different parts of the brain perform different tasks and are involved with different parts of the body.
Who were the key scientists associated with the discovery of localisation of function?
Paul Broca and Karl Wernicke.
What theory was generally supported by scientists before the findings of Broca and Wernicke?
Holistic theory of the brain.
What is lateralisation in the context of brain function?
The concept that some physical and psychological functions are controlled or dominated by a particular hemisphere of the brain.
Which hemisphere of the brain controls activity on the left-hand side of the body?
The right hemisphere.
Which hemisphere of the brain is linked to language?
The left hemisphere.
Fill in the blank: If a certain area of the brain becomes damaged, the function associated with that area will also be _______.
affected.
What is the main part of the brain called?
Cerebrum.
What is the significance of the cingulate gyrus in relation to neurosurgery?
It has been linked to some mental disorders.
True or False: Neurosurgery has shown successful responses in treating mental disorders.
True.
What is one strength of the localisation of function theory?
It has been linked to successful outcomes in neurosurgery for mental disorders.
How does Broca’s area relate to memory according to research?
It is involved in episodic memory.
What does the term cortical specialisation refer to?
Localisation of function in the brain.
How is the cerebrum divided?
Into two symmetrical halves called the left and right hemisphere
How is activity controlled in the brain?
Lateralisation - activity on the LHS of the body is controlled by the right hemisphere and activity on the RHS of the body is controlled by the left hemisphere
How is the cerebral cortex subdivided?
Four centres (lobes):
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
What is a lobe?
A part of an organ that is separate in some way from the rest. Each lobe in the brain is associated with different functions
Describe the frontal lobe.
- at the back of the frontal lobe (in both hemispheres) is the motor area , which controls voluntary movement in the opposite side of the body.
- Damage to this area of the brain may result in a loss of control over fine movements.
Describe the parietal lobe.
- At the front of both parietal lobes is the somatosensory area which is separated from the motor area by a valley called the central sulcus
What is the somatosensory area?
Where sensory information (such as touch) is processed
Describe the occipital lobe.
- At the back of the brain
- Has the visual area
- Each eye sends info from the right visual field to the left visual cortex and from the left visual field to the right visual cortex
Describe the temporal lobe.
- Where the auditory area is
What is the auditory area?
- Analyses speech based information
- Damage may produce partial hearing loss
- The more extensive the damage, the more extensive the loss
What is localisation of function?
The theory that different areas of the brain are responsible for specific behaviours, processes or activities
What is Broca’s area?
An area at the frontal lobe in the left hemisphere responsible for speech production
What is Wernicke’s area?
An area of the temporal lobe in the left hemisphere responsible for language comprehension
What hemisphere is language restricted to?
The left side of the brain
What does damage to Broca’s area do?
Causes Broca’s aphasia which is characterised by speech that is slow, laborious and lacking in fluency
What happens if Wernicke’s area is damaged?
Causes Wernicke’s aphasia. People with Wernicke’s aphasia will often produce nonsense words (neologisms) as part of the content of their speech
One strength of localisation (neurosurgery)?
- Damage to Areas of the brain have been linked to mental disorders
- Neurosurgery is a last resort method for treating some mental disorders, targeting specific areas of the brain which may be involved
- Darin Dougherty et al. (2002) reported in 44 people with OCD who had undergone a cingulotomy
- At post-surgical follow-up after 32 weeks, about 30% had met the criteria for successful response to the surgery and 14% for partial response
- The success of these procedures suggests that behaviours associated with serious mental disorders may be lovalised
Give one strength (evidence from brain scans)
- Supports the idea that many everyday brain functions are localised
- Steven Petersen et al. (1998) used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.
- A study of LTM by Endel Tulving et al. (1994) revealed that semantic and episodic memories reside kn different parts of the prefrontal cortex
- These studies confirm localised areas for everyday behaviours
- Therefore objective methods for measuring brain activity have provided sound scientific evidence that many brain functions are localised
Counterpoint of evidence from brain scans?
- Karl Lashley (1950): removed areas of the cortex (10-50%) in rats that were learning the route through a maze
- No area was proven to be more important than any other area in terms of the rat’s ability to learn the route. The process of learning seemed to require every part of the cortex rather than being confined to a particular area
- This suggests that higher cognitive processes, such as learning, are not localised but distributed in a more holistic way in the brain
One limitation of localisation?
- Language may not be localised just to Broca’s and Wernicke’s area
- Recent review by Anthony Dick and Pascale Tremblay (2016) found that only 2% of modern researchers think that language in the brain is completely controlled by Broca’s and Wernicke’s areas.
- Advances in brain imaging techniques, such as fMRI, mean that neural processes in the brain can be studied with more clarity than ever before.
- It seems that language function is distributed far more holistically in the brain than was forst thought.
- So-called language streams have been identified across the cortex, including brain regions in the right hemisphere, as well as subcortical regions such as the thalamus
- This suggests that, rather than bring confined to a couple of key areas, language may be organised mire holistically in the brain, which contradicts localisation theory
Case study evidence?
- Unique cases of neurological damage support localisation theory (Phineas Gage)
- However problems with case studies are that its difficult to make meaningful generalisations from the findings of a single individual
- Also conclusions drawn may depend on the subjective interpretation of the researcher
