Localisation of function

• Specific areas of the brain have specific functions. For e.g. Broca's area is in the posterior region of the left frontal lobe and is responsible for speech production.

  Cerebral hemispheres

  
• Cortex:

  • visual cortex - receives information from the retina
  • occiptal lobe - processes visual information
  • parietal lobe - perception, making sense of the world
  • somatosensory cortex - processes sensory information from the skin such as touch, pain, temperature
  • motor cortex - sends nerve impulses to the muscles and controls voluntary body movements
  • frontal lobe- contains high level processing areas, e.g. thinking, planning, organising
  • auditory cortex - analyses auditory speech based on the information received from the ears
  • temporal lobe - involved with hearing, language
• Broca's area

  • localised in the posterior part of the left frontal lobe
  • responsible for speech production
  • named after Paul Broca who treated a patient that was able to understand language but not able to speak
  • damage to left frontal lobe leads to slow speech that lacks fluency
  • called ' Broca's aphasia '
  • can understand but have difficulty transforming thoughts into words
• Wernicke's area

  • localised in posterior part of left temporal lobe
  • responsible for understanding language
  • named after Carl Wernicke who discovered this area of the brain
  • patients with damage in this area were unable to understand their own or others language
  • damage to left temporal lope leads to Wernicke's aphasia where a person cannot understand his own or others speech
  • speech is incomprehensible and arranged in a random order
• Evaluation

  Tulving

  • supports the idea that specific parts of the brain are localised for function
  • Ps injected with a small amount of radioactive gold and asked to recall episodic and semantic memories
  • differences found it areas of the brain called prefrontal cortex
  • greater activation in anterior frontal during episodic recall and in posterior frontal in semantic recall
  • suggests that different types of memory are localised to different parts of the brain
• Evaluation

  Tulving- limitation

  • 3/6Ps displayed this difference
  • Tulving himself was a participant along with his wife and another colleage
• Evaluation

  Phineas Gage

  • case study evidence that supports the idea of localisation of function
  • tamping iron passed through his left cheek and behind his left eye, taking most of his left frontal lobe with it
  • the damage to the brain changed the personality, where he went from calm and reserved to rude and quick tempered
  • this was a landmark study showing that personality and impulse control is localised to the frontal lobe
• Evaluation

  Methodology

  • brain scans are an excellent way to show the localisation of function as fMRI can show what parts of a brain are active when performing specific tasks so the evidence has high spatial resolution
• Evaluation

  • symptoms and behaviours of mental disorders are localised
  • purpose of neurosurgery is to remove or destroy certain parts of the brain
  • used to control behaviour in past and is used in extreme cases of OCD where 1/3rd had successful response to surgery
  • thus there is neurological evidence to support the localisation of functioning