Localisation of Function in the Brain

• What is the holistic theory of the brain?

  All parts of the brain process thoughts and actions
• Who argued for the localisation of function in the brain?


  Broca and Wernicke
• What does localisation of function refer to?

  Different brain areas are responsible for specific activities
• What are the functions and damage effects of the motor area in the frontal lobe?

  • Function: Controls voluntary movement in the opposite side of the body
  • Damage: Loss of control over fine movements
• What are the functions and damage effects of the somatosensory area in the parietal lobe?

  • Function: Represents sensory information from the skin
  • Damage: Numbness
• What are the functions and damage effects of the auditory area in the temporal lobe?

  • Function: Analyses speech-based information
  • Damage: Partial hearing loss
• How does the left hemisphere control activity in the body?

  It controls activity on the right side
• How does the right hemisphere control activity in the body?

  It controls activity on the left side
• Which hemisphere is responsible for language?

  The left hemisphere
• What are the functions and damage effects of Broca's area?

  • Function: Responsible for speech production
  • Damage: Broca's Aphasia, slow and non-fluent speech
• What are the functions and damage effects of Wernicke's area?

  • Function: Responsible for language comprehension
  • Damage: Wernicke's Aphasia, production of nonsensical speech
• What does evidence from neurosurgery suggest about mental disorders?

  • Neurosurgery targets specific brain areas
  • Suggests behaviours may be localised
• What did Dougherty et al (2002) report about OCD treatment?

  30% had successful response after surgery
• What did Petersen et al (1988) demonstrate using brain scans?

  Wernicke's area active during listening tasks
• What did Buckner & Petersen (1996) find about memory?

  Semantic and episodic memories are in different areas
• What does evidence in animals suggest about cognitive processes?

  • Higher cognitive processes are not localised
  • Learning requires all parts of the cortex
• What did Dick & Tremblay (2016) find about language localisation?

  Only 2% think language is controlled by specific areas
• How have advances in brain imaging techniques changed our understanding of language function?

  Language function is more distributed than previously thought
• What is a strength for the Localisation of Function in the Brain?

  • Evidence from Neurosurgery
  • Neurosurgery is a last resort method for treating some mental disorders, targeting specific areas of the brain which may be involved
  • Dougherty et al (2002) reported on 44 people with OCD who had undergone a cingulotomy, in which after 32 weeks, 30% had met the criteria for a successful response to the surgery and 14% for a partial response
  • The success of these procedures suggests that behaviours associated with serious mental disorders may be localised
• What is a strength for the Localisation of Function in the Brain?

  • Evidence from Brain Scans
  • Petersen et al (1988) 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
  • Buckner & Petersen (1996) reviewed long term memory studies and found that semantic and episodic memories reside in different parts of the prefrontal cortex
  • Therefore, objective methods for measuring brain activity have provided scientific evidence that many brain functions are localised
• What is a limitation for the Localisation of Function in the Brain?

  • Evidence in Animals
  • Lashley (1950) removed areas of the cortex in rats that were learning the route through a maze
  • No area was proven to be more important than any other area in terms of the rats‘ ability to learn the route and the process of learning seemed to require every part of the cortex rather than a particular area
  • This suggests that higher cognitive processes are not localised but distributed in a more holistic way in the brain
• What is a limitation for the Localisation of Function in the Brain?

  • Language Localisation Questioned
  • Dick & Tremblay (2016) found that only 2% of modern researchers think that language in the brain is completely controlled by Broca’s and Wernicke’s areas
  • Due to advances in brain imaging techniques, we have found that language function is distributed more holistically in the brain than originally thought
  • This suggests that, rather than being confined to a couple of key areas, language may be organised more holistically in the brain, which contradicts the localisation theory