Brain Scanning

• Brain Scanning

  • CAT
  • Uses giant X-ray scan brain
  • Reveal tumours and blood clots
  • Radiation exposure
  • Interpreted by computer
  • May use dye for highlighting
  • PET
  • Inject glucose with radioactive trace
  • Tracer decay, emit gamma rays
  • More active, more glucose; red/orange = high, blue/green = low
  • More invasive than CAT and fMRI
  • fMRI
  • Measure oxygen levels
  • More neural activity more blood flow; meet oxygen demand
  • Detects haemoglobin magnetism
  • Oxygenated (diamagnetic)
  • Deoxygenated (paramagnetic)
  • Bigger change = more intense colour
  • Activation map, compare needs precision
• Brain Scanning Strengths

  • Non-invasive
  • Painless
  • Data is reliable/objective
  • Well-controlled
  • Repeatable
  • Find brain anomalies or active regions in cognitive activities (language, memory, and emotion)
  • fMRI allows detailed brain images with no radiation exposure, unlike CAT and PET
  • Give psychologists invaluable insights into brain structure/activity and various human behaviours
• Brain Scanning Weaknesses

  • Limits participant activiy
  • They must lie still in noisy machines
  • Small movement can distort imaging
  • Many opportunities for interpretation error
  • Lacks eco validity
  • Unable to think naturally in large machine
  • PET/CAT
  • Use radioactivity, exposure has to be limited
  • PET scan radiation is less harmful
  • Still too much is inadvisable
  • Unclear long-term effects
  • fMRI
  • Expensive and not useful for all (metal in bodies)
  • May feel claustrophobic
  • Noisy due to high-powered magnetic fields
  • Require expertise to interpret
  • Complicated statistical analysis