Localisation of function in the brain

• What is localisation of function?

  The theory that different areas of the brain are responsible for different behaviours, processes or activities.
• The brain is divided into two symmetrical halves called left and right hemispheres. As a general rule, activity on the left-hand side of the body is controlled by the right hemisphere and activity on the right-hand side is controlled by the left hemisphere.
• The outer layer of both hemispheres is the cerebral cortex. This is what separates us from other animals because the human cortex is much more developed.
• What is the motor region?

  A region of the frontal lobe involved in regulating movement.
• What is the somatosensory area?

  An area of the parietal lobe that processes sensory information such as touch.
• What is the visual area?

  A part of the occipital lobe that receives and processes visual information.
• What is the auditory area?


  Located in the temporal lobe and concerned with the analysis of speech-based information.
• What is Broca's area?

  An area of the frontal lobe of the brain in the left hemisphere responsible for speech production.
• What is Wernicke's area?

  An area of the temporal lobe in the left hemisphere responsible for language comprehension.
• Damage to Broca's area causes Broca's aphasia which is characterised by speech that is slow and lacking in fluency.
• Wernicke's aphasia is the result of damage to Wernicke's area. Patients who have Wernicke's aphasia will often produce nonsense words as part of the content of their speech.
• AO3 - Brain scan evidence of localisation:

  Petersen et al. used brain scans to demonstrate how Wernicke's area was active during a listening task and Broca's area was active during a reading task, suggesting that the areas of the brain have different functions.
• AO3 - Neurosurgical evidence:

  Dougherty et al. reported on 44 people with OCD who had undergone a cingulotomy - a neurosurgical procedure that involves lesioning of the cingulate gyrus. At post-surgical follow-up, a third had met the criteria for successful response to the surgery. This suggests that symptoms and behaviours associated with serious mental disorders are localised.
• AO3 - Case study evidence:

  An explosion hurled a metre-length pole through Phineas Gage's left cheek and exiting his skull from the top of his head taking most of his left frontal lobe. He survived, yet the damage changed his personality. He had turned from a calm person to a quick-tempered and rude person.
• AO3 - Plasticity:


  When the brain has become damaged, and a particular function has been compromised or lost, the rest of the brain appears able to reorganise itself in an attempt to recover the lost function. This lends support to the holistic theory rather than localisation as the brain is working as a whole unit rather than specific areas for specific functions.