brain scans

Question 1

describe how a CAT scan works

Answer 1

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

Question 2

what is a CAT scan used for?

Answer 2

providing detailed images of soft tissues and vessels
used to diagnose infections and bone fractures
pinpoints tumour location
monitor treatments

Question 3

what a strength of CAT scans (validity)?

Answer 3

detailed images
- 0.27s temporal resolution
- 0.3-0.6mm spatial resolution
makes them good at detecting changes in physical brain structure - identifying tumours early

Question 4

what is the strength of CAT scans (reliability)?

Answer 4

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

Question 5

what is a limitation of CAT scans (ethics)?

Answer 5

uses radiation
same amount in 30 mins as 1-3years normal life
exposure could cause further issues

Question 6

what is a limitation of CAT scans (practicality)?

Answer 6

affected by movement
pregnant people can’t have

Question 7

what is a strength of CAT scans (support study)?

Answer 7

Lusins et al
50 patients with alcoholism
58% had cerebral atrophy which affects the brain with decreased tissue size, loss of neurons
however, the only significant factor was due to the duration of the problem drinking

Question 8

what is a limitation of CAT scans (validity)?

Answer 8

low ecological
correlation

Question 9

describe how PET scans work

Answer 9

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)

Question 10

what are PET scans used for?

Answer 10

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

Question 11

what is a limitation of PET scans (ethics)?

Answer 11

invasive
fluorodeoxyglucose tracer
potential tissue damage - exposure to radiation

Question 12

what is the strength of PET scans (validity)?

Answer 12

high validity
measures what it claims to measure eg speech impairments caused by certain areas of the brain being damaged
however, low eco as an artificial task

Question 13

what is a strength of PET scans (reliability)?

Answer 13

standardised procedure
high is red low is blue
produces same comparable images interpreted same by all researchers

Question 14

what is a strength of PET scans (support study)?

Answer 14

Raine et al
discover if there are brain abnormalities in NGRI murderers
significant differences eg lower glucose metabolism in PFC
however correlational

Question 15

what is a limitation of PET scans (validity)?

Answer 15

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

Question 16

describe how fMRI scans work

Answer 16

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
when neurons become more active, more oxygen is required so blood vessels widen and flow increases which is detected by scanner

Question 17

what are fMRI scans used for?

Answer 17

shows brain activity
identify tumours
look for regions that work when using language or checking memory

Question 18

what is a strength of fMRI scans (ethics)?

Answer 18

no radiation
not invasive

Question 19

what is a limitation of fMRI scans (generalisability)?

Answer 19

no pacemakers
no metal implants

Question 20

what is a strength of fMRI scans (support study)?

Answer 20

Li et al
relationship between chronic heroin use and changes in brain function
significant difference in activation regions associated with reward system
however correlation

Question 21

PET scan resolutions

Answer 21

temporal = 5-10 secs
spatial = 4-5mm

Question 22

fMRI scan resolutions

Answer 22

temporal = 1-4 secs
spatial = 1-2mm

Question 23

what is a strength of fMRI scans (validity)?

Answer 23

developed most recently
modern and advanced technology
most precise - detect smallest changes