Localisation of Function

• What are the four lobes of the brain?

  • Frontal lobe
  • Parietal lobe
  • Occipital lobe
  • Temporal lobe
• Describe the Motor Area:

  • Located at the back of the frontal lobe in both hemispheres
  • Controls voluntary movement
  • Left hemisphere controls the right side of the body and right hemisphere controls left side of the body
• Describe the Somatosensory Area:

  • In the front of the parietal lobe in both hemispheres
  • Represents sensory information from the skin (heat, pressure etc)
  • Information from the right side of the body goes to the left hemisphere and information from the left side of the body goes to the right hemisphere
• Describe the visual area:

  • In the occipital area of both hemispheres
  • Information from the eyes is sent here
  • Information from the right visual field goes to the left hemisphere and information from the left visual field goes to the right hemisphere
• Describe the auditory area:

  • In the temporal lobe of both hemispheres
  • Information from the ears sent here
  • Information from the right ear goes to the left hemisphere and information from the left ear goes to the right hemisphere
• Describe Broca's area:

  • Located in the frontal lobe of the left hemisphere only
  • Responsible for speech production
• What happens if Broca's area is damaged?

  • Causes Broca's Aphasia
  • Slow and garbled speech
• Describe Wernicke's Area:

  • Located in the temporal lobe of the left hemisphere only
  • Responsible for language comprehension
• What happens if Wernicke's is damaged?

  • Causes Wernicke's Aphasia
  • Produce fluent but nonsensical speech
• Strength - Brain scan evidence:

  • Peterson (1988)
  • fMRI scans to show that Wernicke’s area is active during a listening task, whereas Broca’s area is active during a reading task.
• Strength - Neurosurgery Evidence:

  • Doughety (2004)
  • Studied 44 OCD patients who had a cingulotomy (surgery on parts of the frontal lobes)
  •  The surgery was found to have a 32% success rate  and a 14% partial success rate.
• Limitation - Too simplistic:

  • lashley
  • Taught rats to navigate a maze, then removed parts of their brains.
  • Could not find a specific area responsible for their memory of the maze.
  • Proposed the equipotentiality theory
• What is the equipotentiality theory?

  Basic functions like movement are localised, but higher functions (e.g. memory, cognition) are spread throughout the brain.
• Strength - Case Study Support:

  • Phineas Gage
  • Severe brain damage due to pole being fired through head
  • Retained most functions of the brain with only some slight shifts in personality

  Counterpoint - Old study so lacks temporal validity and only specific to one person so not generalisable