Localisation of functions

• What are the different parts of the brain?

  Label below:

  A) Frontal lobe

  B) Parietal lobe

  C) Occipital lobe

  D) Temporal lobe

  E) auditory area

  F) Broca's area

  G) motor area

  H) somatosensory area

  I) visual area

  J) Wernicke's area

  
• What is the motor area responsible for?

  Regulates movement
• What is the somatosensory area responsible for?

  Process sensory information
• What is the visual area responsible for?

  Receives and processes visual information
• What is the Wernicke's area responsible for?

  Language understanding
• What is the auditory area responsible for?

  Analysis of speech
• What is the Broca's area responsible for?

  Language and speech production
• What two functions in the brain are only on the left side?

  Broca's area and Wernicke's area
• What is evidence from brain scans of localised functions?

  When tested under a FMri scanner:

  Wernicke's area was active during a listening task

  Broca's area was active during a reading task
• What is evidence from neurosurgery about localisation of functions?

  Patients were kept awake during neurosurgery to see active areas when they complete certain tasks. Stimulating these areas can be associated with their brain functions (e.g. Broca's area -> slurred speech)

  This helps improve the quality of people's life as neurosurgeons can prevent excessive damage on these areas
• Name a case study evidence of localisation of functions

  Phineas Gage -> while working on the railroad, he accidentally caused an explosive to shoot an iron rod through his left cheek and skull, and taking a portion of his brain (mostly from the frontal lobe)

  • Gage survive but there was a personality change according from his peers, the once calm and reserved man turned to a quick-tempered and rude one, his peers described him as 'No longer Gage'
  • This suggests the frontal lobe may be responsible for regulating mood
• What is a disadvantage of generalising a case study such as Gage's

  Anecdotal - lack of reliable evidence

  • We do not know what happened in Gage's past, only after the accident, we cannot be certain there was a shift in personality or if the shift was related to the accident or not
• What did Lashley conduct research with?

  Rats
• What did Lashley do with the rats to test localisation?

  Removed areas of the cortex (10%-50%) in rats that were learning a maze

  • He found that the rats' performance were not affected by this
  • Shows learning is distributed across whole of brain, requires every part of the cortex
  • Highly cognitive functions such as learning is too complex to be localised - COUNTEREVIDENCE of localisation
• What is the concept of plasticity?

  The ability of the brain to change and adapt -> when the brain becomes damaged through illness or accident and a particular function becomes compromised or lost, the rest of the brain appears to be able to reorganise itself in an attempt to recover the lost function (Lashley describes this as the Law of Equipotentiality)
• What is an real life example that demonstrates plasticity?

  Jodie - had severe seizures on her left side at the age of 3, this lead to the right hemisphere of her brain removed, she demonstrated remarkable brain plasticity by adapting and living a relatively normal life now

  • Contradicts localisation of function as the brain can rewire itself following damage
• What type of evidence are brain scans?

  Scientific
• Neurological evidence from the past

  Early attempts of removing areas of the brain, lobotomy (developed by Freeman), were imprecise and caused damages to connections in the frontal lobe in an attempt to control aggressive behaviour
• What are neurological evidence for localisation nowadays?

  Neurosurgery used today for extreme cases of OCD and depression, such as a cingulotomy (lesioning of the cingulate gyrus)showed a successful response post surgery, suggesting that symptoms and behaviours associated with serious mental disorders are localised