Brain scans

• CAT scans

  Series of x-rays and combining them to form a comprehensive two or three dimensional picture of the area being scanned
• Process of a CAT scan

  Dye injected into patient as a contrast material

  Placed in a cylindrical CAT scan machine that takes the pictures
• Example of CAT scan

  Johnstone et al

  CAT scans to show that the brains of people with schizophrenia were different to normal brains

  fluid filled spaces much larger
• EEG

  the only method available in the 1950s

  Electrodes placed on the scalp and electrical activity in different parts of the brain can be recorded
• Example of EEG

  Dement and Kleitman

  Detecting different stages of sleep

  Found that participants were more likely to report having a dream if awoken during REM sleep
• MRI scan

  Use of magnetic field that causes the atoms of the brain to change their alignment when the magnet is on and emit various radio signals when the magnet is off
• Process of a MRI scan

  Takes repeated images of the brain
• Example of MRI scan

  Maguire et al

  MRI to demonstrate that taxi drivers had larger hippocampus

  Supporting the view that this area is important in spatial memories
• PET scan

  Administer slightly radioactive glucose

  The most active areas of the brain use glucose and radiation detection can see the radioactive areas
• Example of PET scan


  Raine et al PET scans to compare brain activity in murderers and normal individuals

  Differences were found in areas such as the amygdala

  However - does not demonstrate that violence is caused by biology alone
• Advantage of PET scan

  Reveal chemical information that is not available with other imaging techniques

  E.g. distinguish between benign and malignant tumours

  Show the brain in action
• Disadvantage of PET scan

  Costly technique

  Patient has to be injected with radioactive dye - can only be used a few times

  Less precise than MRI scans
• Advantage of CAT scans

  Useful for revealing abnormal structures

  e.g. rumours or structural damage

  Quality of images and is much higher than of traditional x-rays
• Disadvantage of CAT scans

  Require more radiation than traditional x-rays

  The more detailed and complex, the more radiation exposure to patients

  Only provide structural information
• Advantage of MRI scans

  More detailed images of the soft tissue in the brain

  Does not expose patient to hazards of radiation

  Can undergo examination several times in short term
• Disadvantage of MRI scans

  Take a long time

  Uncomfortable for patients