Localisation of Brain Function & Hemispheric Lateralisation

• what two functions are lateralised to the left side of the brain?

  language

  analytical thought
• what two functions are lateralised to the right side of the brain?

  creativity

  drawing
• corpus callosum: joins the two hemispheres together and transfers information across the two
• contralateral control: the left side of the brain controls the right side of the body, the right side of the brain controls the left side of the body
• who conducted research on spilt brain patients?

  sperry
• sperry's study on split brain patients

  hemispheres were unable to communicate with each other because the corpus callosum was cut
• what did sperry find from his research on split brain patients?

  when an object was placed in the right hand, it was seen by the left hemisphere and was able to be described, this shows that language is lateralised to the left hemisphere

  when an object was placed in the left hand, it was seen by the right hemisphere and could not be described, this shows that language is not lateralised to the right hemisphere
• what is a strength of sperry's research on split brain patients?

  high reliability as standardised procedures allow for replicability
• what is a limitation of sperry's research on split brain patients?

  cannot be generalised as was performed on epileptic patients, we do not know if the study is measuring split brain research or damage from epilepsy
• how can sperry's study be improved?

  compare to epileptic patients who have not undergone split brain surgery
• localisation of function: the theory that specific areas of the brain are responsible for specific functions
• frontal lobe: responsible for speech and thought learning
• motor cortex: located in the frontal lobe, responsible for voluntary movements
• parietal lobe: stores sensory information
• somatosensory cortex: located in the parietal lobe, stores sensory information
• temporal lobe: responsible for hearing and memory
• auditory cortex: located in the temporal lobe, analyses speech based information
• occipital lobe: processes visual information
• visual cortex: located in the occipital lobe, stores visual information
• wernicke's area: located in the left temporal lobe, makes sense of what's being said (speech comprehension)
• broca's area: located in the left frontal lobe, generates an answer and transfers to motor cortex which says the answer
• what case study is used as supporting evidence for broca's area?

  patient tan
• patient tan case study

  could only say one syllable, post mortem, damage found to the left frontal lobe
• how is broca's research supported?

  studied a further 8 patients with a similar language deficit and found the same area of damage, also studied a further 8 who had no language deficit and damage was to the right side instead
• what is a limitation of broca's research?

  post mortem reduces validity as unhealthy dead brains cannot be generalised to healthy living brains
• what is modern supporting evidence for broca and wernicke's area?

  peterson - used brain scans - during reading tasks broca's area lit up and during listening tasks wernicke's area lit up - supports localisation of function for these two areas
• what research is against the theory of localisation of function?

  functional recovery research
• how is functional recovery research used against the theory of localisation of function?

  brain plasticity: left hemisphere removed but right hemisphere can take over the function of language so shows no localisation
• what does karl lashley argue about the theory of localisation of function in the brain?

  basic motor and sensory functions are localised but higher mental functions, such as memory, are not