brain scan cards! Flashcards
Outline of how fMRI scans work
patient performs tasks whilst in scanner eg moving fingers
head placed in powerful electromagnet
magnetic field inside scanner which is formed between the electromagnet and a nuclei of atoms and detects the changes in blood oxygen levels in specific areas of the brain via radio signals to determine neural activity
what are fMRI scans used for?
Shows brain activity, identifies tumours, looks for regions that work when using language or checking mmeory
strengths of fMRI scans?
Non-invasive so ethical, provides exact locations of increased neural activity during tasks
limitations of fMRI scans?
Unable to detect activity of individual neurons, ppts need to remain still, no pacemakers and no metal implants (generalisability)
describe how a CAT scan works?
tunnel machine
inside of machine rotates and takes x rays at various angles
x rays are sent to computer which creates a cross sectional image
30 mins
what is a CAT scan used for?
providing detailed image of soft tissues and vessels, used to diagnose infections and bone fractures
strengths of CAT scans?
detailed images of 0.27 temporal resolution, makes them good at detecting changes in physical brain structure identifying brain tumours easily
what is a strength of CAT scans (reliability)?
standardised procedure
- many x rays taken by rotating machine
- cross sectional image composed of these
- same structure shown every time a scan is done
allow to check for consistency
what is a limitation of CAT scans (ethics)?
uses radiation eg same amount in 30 mins as 1-3 years normal life
exposure could cause further issues + no pregnant people
describe how PET scans work
cylinder tunnel scanner
measures metabolic activity
fluorodeoxyglucose radiotracer injected into arm
45 mins to reach cells and collect in body, needs time to decay
scanner detects radiation
most active areas use more (red) less active use less (blue)
what are PET scans used for?
shows how well parts of the brain are working
investigate response to treatment
measures blood flow & oxygen use
identify brain disorders eg parkinsons or epilepsy
what is a limitation of PET scans (validity)?
- results hard to interpret
- PET scans on people doing same task show diff brain activity in diff people
- hard to draw conclusions about which brain areas link to which behaviours
what is a limitation of PET scans (ethics)?
invasive
fluorodeoxyglucose tracer
potential tissue damage - exposure to radiation
what is a strength of PET scans (validity)?
high validity
measures what it claims to measure eg speech impairments caused by certain areas of the brain being damaged
however, low eco as artificial task
what is a strength of PET scans (reliability)?
standardised procedure
high is red, low is blue
produces same comparable images interpreted same by all researchers