Brain scans

• What is the purpose of brain scanning ?

  Scans are used to study biological and psychological aspects of functioning such as thinking, remembering using language, and by using them we can identify areas of the brain that work when certain processes are taking place
• CT scans

  • uses x-rays and a computer to create detailed structured images of the inside body(brain)
  • each image taken is a cross-section of the persons brain
  • +useful for revealing abnormal structures in the brain such as tumours and the quality of the images is much higher than usual x rays
  • -they do require more radiation which can be harmful
  • -CT scans also only provide structural information unlike PET scans which show activity within the brain
• PET scans

  • these measure the metabolic activity in the brain- where is active
  • person is injected with a small amount of a radioactive substance which identified which areas of the brain uses it
  • active areas are coloured red or yellow and least active areas blue
  • +useful for research as they show the brain in action, Raine 1997 used them to identify areas associated with aggression
  • +indicate the specific areas involved with an experience - providing the localisation of function
  • -results can be difficult to interpret
  • -ethical issues regarding the injection of radioactive substances as can damage tissues of the body killing cells which means the technique cannot be carried out often- limiting
• FMRI scans

  • these use radio waves to measure blood oxygen levels in the brain
  • the activity of the brain is picked up through radio signals producing images of the brain
  • +does not use radiation and so it is a very safe method of studying the brain
  • -expensive
  • -patient will need to remain very still