Brain Scans Flashcards
What do PET scans allow us to see?
Activity in the brain - which parts are using glucose
How do PET scans work?
Radioactive chemical dye is injected into the blood, as the chemical breaks down it releases radioactivity which can be picked up on the scan
The more active the brain, the more radioactivity will be picked up by the scan
What does a PET scan produce?
Colourful image
Darker/warmer areas = red = more activity
Lighter/cooler areas = blue = less activity
What do fMRI scans use to measure function?
Magnetic and radio waves
How do fMRI scans work?
A person lies in a large cylinder perfectly still
Magnet and radio waves are sent through the body
As neutral activity increases in the brain, blood flow increases, requiring more oxygen
Builds an image based on haemoglobin
How is oxygen carried?
Via haemoglobin in red blood cells
What does the haemoglobin do when it is full of oxygen?
Repels magnetic field (diamagnetic)
What does the haemoglobin do when it is deoxygenated?
Follows magnetic field (paramagnetic)
What is the MRI and structure?
Body’s water molecules inside the MRI magnet line up so they face either North or South - previously randomly arranged
What do CAT scans involve?
Focused X-Ray beam being beamed into the brain
How are CAT scans done?
Many angles to form a full picture as X-Ray is only a 2D image
What do CAT scans let us see?
Structure of the brain for damage or tumours
How does Raine support PET scans?
Found differences in brain activity between murderers and non-murderers by using PET scans so develops our understanding of how brain activity can influence behaviour
Why do PET scans lack ecological validity?
Artificial setting so results are harder to apply to real life situations
Why are PET scans scientific?
Objectively measure brain activity directly
