Brain scans Flashcards
name 3 types of brain scans?
- PET scans
- fMRI scans
- CAT scans
what is a PET scan?
type of scan that allows researchers to see activity within the brain
how do PET scans work?
1-radioactive dye injected into blood(irradiate glucose)
2-as it breaks down-released radioactivity-picked up on scan
what does darker/warmer colour mean on PET scans?
more activity
what does lighter/cooler mean on PET scans?
less activity
what does red/orange show on PET scans?
high activity
what does blue/green show on PET scans?
low activity
what are STRENGTHS of PET scans?
- good contribution to research e.g Raine
- Brain scans can be easily repeated
- objective and scientific
what are WEAKNESSES of PET scans?
-lack ecological validity
frequent exposure to radioactivity-unethical-invasive-dangerous
what is an fMRI scan?
use magnetic and radio waves to measure function
How do fMRI scans work?
1-ppt lies in large cylinder-must be perfectly still
2-magnet and radio waves are sent through the body
3-as neural activity increases in brain, blood flow increases n active areas-requires more oxygen
4-haemoglobin repels magnetic field-follows field when deoxygenated-uses these changes to build up an image
5-inside MRI magnet-all of body’s water molecules(previously arranged)now line up so facing either north or south
how is oxygen carried through the body?
haemoglobin in red blood cells
what are STRENGTHS of fMRI scans?
- easily repeatable
- objective/scientific-measures brain activity directly in the brain
what are WEAKNESSES of fMRI scans?
- -lacks ecological validity
- people with pacemakers may not be able to take part-magnetic
what are CAT scans?
involve focused x-ray beam being beamed into the brain
