brain scanning techniques

Question 1

what are CAT scans

Answer 1

computerised axial tomography

structural images
x rays
cross sectional
donut shaped scanner rotated around the body
10 - 20 min

Question 2

evaluate CAT scans

Answer 2

+ detect areas of brain dange following acident
+ quick
+ good quality images
+ non invasive and painless
- c rays should be used spairingly, not ideal for research, could incrase risk of cancer
- dont show function like PET or fMRI

Question 3

what is a PET scan

Answer 3

position emission tomography

activity based on colour, more active = red, less active = blue
3d images
compare well functioning brains wil malfunctioning
diagnose conditions that affect normal workings
performance tasks
radioactive tracter injected into blood, wait 1 hour
scan takes 30 min

Question 4

evaluate PET scans

Answer 4

+ shocw brain in action, useful for psychological research, Nora Volkow et al looked at the corelation of number of dopamine transporters ocupied by cocaine and ppts subject ecperience to drug, biological activity linked to behaviour
+ show specific areas involved in experience
+ reliable, replicated
+ valid as they meaure what they claim
+ movement doesnt ruin scan
+ maguire found different brain areas activated in taxi drivers recalling familiar routes then recall of familiar film sequence
- ethical issues with radioactive glucose, cause damage to tissues, mutations in DNA, limits use in psychological research
- slightly invasive
- not easy to interpret
- difficult to isolate brain functioning, less valid

Question 5

what is fMRI scan

Answer 5

functional magnetic resonance imaging

magnetic fields and radio waves
shows which parts of the brain are activated when certain task caried out
bllod oxygen level meausred
blood is directed to active area
haemoglobin carries oxygen and repels magnetic field

Question 6

evaluate fMRI scans

Answer 6

+ shows which areas of the brain are being used at one time, cognitive tasks carried out
+ more ethical, doesnt use radiation
+ scientific, reliable and relicable
- lack ecological validity, artificail setting
- brain is never at rest, not totaly sure which parts active
- tiny movement can ruin scan, limits use as research method