Bio Psy - Brain Scans

• 3 Types of Brain Scans

  • fMRI
  • PET
  • CAT
• fMRI

  • Produces a detailed image showing the structure of the brain and brain activity​
  • Based on:​
  • Increased neural activity = increased blood flow to an area of the brain​
  • Scanners electromagnets point protons in the same direction​
  • Radio waves passed through the head distort them = detected​
  • More H = paler, less H = darker​
  • Oxygenated haemoglobin repels magnetic field, but deoxygenated follows the direction of the magnetic field. These changes cause an image on the scanner​
  • The computer maps it out to show changing levels of neural activities during tasks
• fMRI :) Scientific

  Scientific equipment, can be repeated and analysed. T/f objectively analysed, high validity
• fMRI :) Non-invasive

  Non-invasive procedure, no foreign substances. T/f less harmful​
• fMRI :( Ecological Validity

  artificial lab, activity may not be reflective, t/f cant be
• fMRI :( Expensive

  requires specialist staff, machinery etc. T/f limit use as might not have sufficient resources​
• PET

  • Produces picture of functioning brain activity​
  • Injected with radioactive tracer which bonds to glucose​
  • Ppant does task and most active brain areas absorb glucose, leaving radioactive material remaining which produces gamma rays​
  • More gamma rays = more blood flow = more brain activity = more RED​
  • Less = blue
  • Cannot be used by pregnant women
• Eval for PET

  :) Scientific

  :) Practical Applications - RAINE

  :( Invasive

  :( Ecological Validity
• CAT

  • Produces image of any body part​
  • Multiple x ray beams passed through. Taking images of slices of body part which can make a 3D image​
  • Picks up how the area reacts to the x-ray, showing how far it is blocked – shows if a tumour is present​
  • Can produce a computer image of the brain
• Eval for CAT

  :) Non invasive​

  :) Scientific

  :( Eco val

  :( exposure to radiation