Localisation of function in the brain

• Localisation of function

  Theory that different areas of the brain are responsible for specific behaviours, processes or activities.
• Localisation versus holistic theory

  • 19th century - Paul Broca and Karl Wernicke (scientists) discovered that specific areas of the brain are associated with particular physical and psychological functions.
  • If a certain area of the brain becomes damaged through illness or injury, the function associated with that area will also be affected
  • Before these investigations and before the case of Phineas Gage - scientists generally supported the holistic theory - that all pats of the brain were involved in the processing of thought and action
• Hemispheres of the brain


  Main part of the brain(cerebrum) is divided into two symetrical halves called the left and right hemisphere
• lateralisation

  when some of our physical and psychological functions are controlled or dominated by a particular hemisphere.
• General rule of lateralisation 


  Activity on the left hand side of the body- controlled by right hemisphere

  Activity on the right hand side of the body is controlled by the left hemisphere.
• The cerebral cortex


  Outer layer of both hemispheres
• The cortex of both hemispheres is subdivided into four centres-lobes of the brain


  the frontal lobe

  the parietal lobe

  the occipital lobe

  the temporal lobe
• Lobe


  part of an organ that is seperate in some way from the rest
• frontal lobe

  At the back of the frontal lobe is the motor area which controls voluntary movement in the opposite side of the body.
• Parietal lobe


  At the front of both parietal lobes is the somatosensory area- An area of the parietal lobe that processes sensory information such as touch
• occipital lobe


  In the occipital at the back of the brain is the visual area or visual cortex
• Damage to the hemispheres(eye)


  each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex. Damage to the left hemisphere can produce blindness in part of the right visual field in both eyes.
• temporal lobes


  house the auditory area- analyses speech based information
• Brocas area


  Area of the frontal lobe in the left hemisphere(most people) - responsible for speech production - identified by paul broca - Damage to this area causes brocas aphasia -slow speech lacks fluency
• Wernickes area


  Area of the temporal lobe in the left hemisphere(in most people) responsible for language comprehension -Karl wernicke- damage leads to wernickes aphasia