3.LOCALISATION

• What is localisation of function

  Localisation of function is the idea that particular behavioural functions such as moving your arm or producing speech are localised to particular regions in the brain
• What are 6 specific regions

  occipital lobe/visual cortex, somatosensory cortex, motor cortex, auditory cortex
• What is hemispheric lateralization

  Hemispheric lateralisation is when each side of the brain [hemispheres] is specialised to perform different functions
• What is the left hemisphere specialised in

  The left hemisphere is specialised in language
• What is the right hemisphere specialised in

  visuospatial tasks are best performed by the right side of the brain
• What does contralateral mean

  Contralateral explains how each hemisphere of the brain controls the opposite side of the body including both motor and sensory pathways and vision of the contralateral visual field
• What is the cortex

  The cortex is the surface layer of the brain referred to as grey matter and contains mostly cell bodies
• What is the occipital lobe/visual cortex [where is it found + job]

  This is the smallest part and is found in the back of the brain.It is known as the visual processing centre where each hemisphere occipital lobe receives information from the contralateral visual field.
• What does damage to the occipital lobe lead to

  Damage to this lobe will lead to partial or complete loss of vision called cortical blindness and if there is damage to one cortex this can lead to loss of vision in the opposite visual field
• What is the motor cortex

  Motor cortex is at the back of the frontal lobe and the somatosensory cortex is at the from of the parietal.They are divided by a fold called the central sulcus and are contralateral
• What does damage to the motor lead to

  the motor cortex is the area of the brain which is responsible for voluntary motor movements [e.g. deciding to move your arm] and is contralateral
• What is the somatosensory cortex

  this area of the brain is responsible for receiving sense impressions from around the body and is contralateral
• What does damage to the somatosensory cortex lead to

  Damage to this cortex will lead to a loss of sensation and there will be the loss of the ability in recognising objects by their feel [agnosia].These effects will be contralateral
• What is the auditory cortex

  this cortex receives and process sound information from the ears and is located in both hemispheres and located at the top of the temporal lobe
• What does damage to the auditory cortex lead to

  Dthis cortex receives and process sound information from the ears and is located in both hemispheres and located at the top of the temporal lobe
• What is the Broca's area

  This is located in the left frontal lobe and is responsible for speech production and was discovered after the case study of a man who understood speech but only seemed to respond with the word tan. The post mortem of their brain shows that there was severe damage to the bottom of the frontal lobe
• What does damage to the Broca's area lead to

  Damage to the Broca's area will lead to Broca's aphasia which is also known as expressive/motor aphasia leading to difficulty in producing speech or speech will be low and effortful leading to some people speaking in poor grammar
• What is the Wernicke's area

  This area is located in the top temporal lobe, wernicke's area is responsible for speech comprehensions and this was discovered after cases of individuals who could produce fluent sounding speech that made little sense
• What will damage the Wernicke's area

  Damage to the Wernicke's area: Damage to this area will lead to wernicke's aphasia in which people have difficult understanding speech or written language
• Explain the brain scan evidence in support of localisation of function

  Clinical case study research demonstrates loss of certain functions if damage is caused to particular area of the brain eg Broca and wernickes case studies [aphasia] and Clive wearing [amnesia]-suggesting functions are localised in these areas.One example is Petersen et al who used brain scans to demonstrate how Wernicke's area was active during a listening task and Broca's was active during a reading task, suggesting that these areas of the brain have different function.In addition another study was Tulving study on long term memory in which revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.
• Explain the neurosurgical evidence in support of localisation of function

  The practice of removing areas of the brain in attempt to controlling behaviour developed in the 1950s leading to lobotomy where there was severing of the frontal lobe in order to control aggressive behaviour.Even today neurosurgeon is used for extreme cases such as OCD and Depression.For example,Dougherty et al [2002] reported on 44 OCD patients who had undergone a cingulotomy [ a neurosurgical procedure that involves lesioning of the cingulate gyrus] At a post-surgical follow up after 32 weeks, a third had met the criteria for a successful repose.The success of the procedure suggests that symptoms and behaviours associated with serious mental disorders are localised
• Explain case studies against localisation of function

  The use of case studies are seen as unscientific, especially in brain research with damage often covering multiple regions, as seen when modern MRI scans were made of Tans brain
• Explain the study of Lashley against localisation of function

  PROCEDURE: 50 rats ran a maze before and after areas of their brain cortex were destroyed. Lashley found ability to successfully re-run the maze was affected by how much brain cortex was destroyed not which area The work of lately suggested that higher cognitive processes such as learning and memory are not localised but distributed across the brain.
• Explain the study of plasticity against localisation of function

  The idea of plasticity is that when the brain has become damaged and a particular function has been compromised or lost, the rest of the brain appears able to reorganise itself in an attempt to recover the lost function Lately described this as the law of equipotentiality whereby surviving brain circuits 'chip in' so the same neurological action can be achieved.Although this does not happen every time, there are several documented cases of stroke victims being able to recover those abilities that were seemingly lost as a result of the illness