CAT, PET, FMRI Scans

Question 1

Describe PET scans

so give the instructions on how’s its carried out, how it produces the images and how is it used in research by psychologist (do it in this order)

Answer 1

1. patients are injected with radioactive tracer. once in brain cell the tracer decays, it emits positrons this is done by the uptake of oxygen in the water or glucose
2. scanner detects the metabolism level of the injects substance. (e.g. glucose) mildly radioactive = reveals which parts of the brains are most active (amount of energy used) over period of minutes.
3. (goal = identify damage/ tumours) this is done by showing malfunction via the levels of activity: blue (low)= low red (medium) = red (high)
4. used in research by injecting patient with tracer and given a task to stimulate the part of the brain that needs to be checked up on
5. by emitting abnormal levels of activity = helps see where the problems exist + predict the issues that can occur in the future therefore can proceed with early prevention

Question 2

Give an example of PET scancs

Answer 2

Raine et al (1997): - investigated differences between the brains of murderers and non-murderers.

• mapped abnormal brain activity in the murderers’ group in areas of the brain associated with impulsivity and risk-taking behaviour
• therefore can explain increase aggression

Question 3

Strengths of PET scans

Answer 3

• data is objective (Quantitative data): measure the volume of activity down to the pixels.
• shows clear cause and effect = pinpoint location
• detailed standardised procedure = easily replicable and test its reliability
• application to real life as able to see potential issues early and have introduce early prevention.

Question 4

Weakness of PET scans

*invasive is basically when something stimulates the body such as radzs and electricity, is it able to do that in different location. (afterwards the client tells if they can feel the sensation or not)

Answer 4

• More invasive than other techniques (involve injections and radioactive) – ethical concern
• Can’t pinpoint locations of the cause of the area, only an estimate location
• process is able to influence the activity of participants brain - lessen validity (increase participant variable)
• Radioactive treatment = can cause long term effects (risky)

Question 5

Describe FMRI scans

so give the instructions on how’s its carried out, how it produces the images and how is it used in research by psychologist (do it in this order)

Answer 5

1. shows images of brain activity but doesn’t uses radiation. Patients are given a task whilst in the scanner (has procedures of choice)
2. the technique is that brain activity is associated with blood flow in the brain and this activity is used to gather info by scanner to produce a still image (like an X-ray + many slices of the brain )
3. its inside a larger scanner and passes a strong magnetic field through the head. shows metabolic activity second by second without injected tracers
4. to shows which is active a neutral activity increase the amount of energy the brain needs hence blood flow increase in the active areas to keep up with constant demand of oxygen (gives the coloured parts of the scan)
5. image also shows the damage of tumours and if need treatment. while task is being completed the scanner sends info to PC, maps any signs of activation to show changing levels of neutral activity in diff parts of the brain

Question 6

Give an example of FMRI scancs

Answer 6

Matthies et al. (2012):

• measured volume of amygdala in 21 female volunteer
• found significant correlation when testing for relationship
• amygdala houses aggression in the brain but the results shows that a smaller amygdala = higher aggression
• suggest MRI scans can be helpful in finding where aggression might be in the brain

Question 7

Strengths of FMRI scans

Answer 7

• Can show pinpoint location hence more likely to show you cause and effect.
• Reliable = have standardised procedure and Is really controlled hence able to be replicable and test said reliability
• Ethically acceptable as the equipment utilise magnets not radiation therefore can do multiple check on the same patient

Question 8

Weakness of FMRI scans

Answer 8

• Practically its shit as the patients need to stay still for almost 2 hours because if they move the image will be blurred and ruin the data.
• no generalisability: people that are old, has plates in the body and pregnant women cant take the scan = creates a narrow sample

Question 9

Describe CAT scans

so give the instructions on how’s its carried out, how it produces the images and how is it used in research by psychologist (do it in this order)

Answer 9

1. any part of the body is suitable, quick and gives accurate detail of brain structure (helps guide clinicians in decision making regarding treatment or surgery)
2. passes through an X-ray into the head (multiple beams and angles into the head = gather more info)
3. beams are interpreted by PC and then detailed image of the brain can be seen. useful to detect area of brain damage following an accident or the positioning of tumours in the brain.
4. use of X-rays = exposure to radz. only approved of proceeding if benefits heavily outweighs the potential risk
5. can help surgeons plana procedure before surgery as it contains an accurate layout of the brain’s structure

Question 10

Give an example of CAT scans

Answer 10

Lusins et al., (1980): Alcoholism and cerebral atrophy:
- A study of 50 alcoholic patients was carried out with CAT scans of their brains.

• alcohol and drug free, and without neurologic or psychiatric disorders at the time of the examinations.
• Fifty-eight percent of the patients had cerebral atrophy.
• Atrophy can be generalized, which means that all of the brain has shrunk; or focal, so basically decrease the level of control that effects the limited area
• cerebral hemispheres are effected = conscious thought & voluntary processes may be impaired

Question 11

Strengths of CAT scans

Answer 11

• Quick scanning technique = able to make quick decisions in medical procedures
• Really objective (anyone can identify what the problem is) and procedure is scientific as data is quantitative and follows a standardised procedure
• more available options as its utilize invasive techniques

Question 12

Weakness of CAT scans

Answer 12

• practically is also shit = unable to move during the duration of scanning hence the image will be blurred and become useless
• Cant use the same participant as it involves a radiation risk from the X-rays = limited use
• Investigate only the structure hence doesn’t investigate cause and effect