Localisation of function

• key areas

  A) wernickes area

  B) somatosensory

  C) auditory

  D) brocas

  
• motor cortex is responsible for generation of voluntary motor movements
• the motor cortex is located within the frontal lobe
• the motor cortex covers both hemispheres
• somatosensory cortex detects sensory events arising from different regions of the body - produces sensations
• the somatosensory cortex is located in the parietal lobe
• the somatosensory cortex is located within both hemispheres
• visual cortex receives, segments and intergrates visual info
• the visual cortex is located in the occipital lobe
• the visual cortex is within both hemispheres
• auditory cortex is where sound waves are converted into nerve impulses (detect sound)
• auditory cortex is located mostly in the temporal lobe
• auditory cortex is located within both hemispheres
• brocas area is the 'language centre' - there are 2 sides including 1 for language and the other for responding to cognitive tasks
• brocas area is located in the frontal lobe
• brocas area is located on the left hemipshere
• information is transferred to wernickes area then recognised as language and associated with meaning
• wernickes area is located in the left temporal lobe
• wernickes area is located in the left hemisphere
• different parts of the brain are responsible for particular functions
• localisation of function is the idea that certain functions (language or memory) have certain locations within the brain
• evaluation - limitation

  • brocas area -language production not be limited to that area alone
  • dronkers at al studied brains-2 of brocas patients - MRI imaging - found other areas besides brocas area could have contributed to the patients reduced speech abilities
  • although lesions to brocas area can cause temporary speech disruption - dont usually result in severe disruption of spoken language suggests language and cognition are complicated and involve networks of brain regions rather than being localised to specific areas
  • brocas area alone does not appear to be responsible for language production
• evaluation - limitation - individual differences

  • limitation with localisation of function is that there are individual differences
  • Bavelier et al found study of silent reading -variety of areas of brain were activated (right temporal lobe). harsty et al found women have larger brocas and wernickes area than men
  • problem for LOF as suggests that where functions are located in brain it is not same for everyone
  • individual differences mean its not possible to generalise same assumption to everyone
• brocas and wernickes area are both language centres
• evaluation - strength - research to support

  • research supporting 2 language centres from aphasia patients
  • excessive aphasia (brocas aphasia) is impaired ability to produce language caused by brain damage in brocas area. receptive aphasia (wenickes aphasia) is impaired ability to understand language + extract meaning from words
  • shows importance of brocas area in production of language and wernickes area in understanding of language
  • localisation of function is supported by aphasia patients
• evaluation - limitation

  • argued brain areas communicate with each other is more important than what region is responsible for what process
  • wernicke claimed different regions are interdependent -they must interact with others - dejerine described case -loss ability to read due to damage in connection in wernickes area/visual cortex
  • complex behaviors build up gradually as stimulus enters - moves to different structures before response is made- connection damage results in impairments
  • arguably more important to focus on how areas of brain communicate as well as where functions are located
• evaluation - limitation

  • not all psychologists agree with view cognitive functions are localised in brain
  • lashley introduced equipotentiallly theory - basic motor/ sensory functions are localised but higher mental functions are not - argued inact areas of cortex could take responsibility for cognitive functions
  • support - humans regaining some of cognitive abilities following damage to areas in brain - suggests functions not limited to one spec area
  • evidence to suggest some functions can be carried out by different areas in the brain