Brain Scanning

Question 1

How do CAT scans work?

Answer 1

• Person lies inside a large donut shaped scanner
• Scanner rotates multiple x-rays around them to produce a cross sectional image of the brain regions
• Images of brain are taken from different angles
• When all the slices are put together this can build up a very detailed picture
• A cat scan is good for detecting changes in physical structure so is valuable when looking to tumours

Question 2

Evaluate a strength of a CAT scan

Answer 2

P- Good at detecting anomalies in the brain
E- Much more detailed than a regular x-ray due to cross-sectioning, generating 3D images
E- Tumours and other mutations can be easily identified

Question 3

Evaluate a weakness of a CAT scan

Answer 3

P- Cannot be used often
E- Patients exposed to radiation
E- Can cause health problems, such as cancer and would not be suitable for some people, such as pregnant women, which limits the scans effectiveness

Question 4

How do PET scans work?

Answer 4

• Patients injected with radioactive glucose tracer = FDG
• Most active brain areas will use more glucose
• Glucose atoms breakdown the absorption, producing gamma rays that are picked up
• Information is sent to a computer
• Most active areas = red
• Least active areas = blue

Question 5

Identify a study that used a PET scan

Answer 5

P- Raine et al
E- Used PET scans to find out if there is a difference between NGRI’s and non- murderers in relation to brain structure. He found that NGRI’s showed less activity in the frontal lobe, especially the pre-frontal cortex which is associated with rational thinking, self-restraint and memory
E- This therefore suggests that brain abnormalities in the NGRI’s might translate into violence, due to higher activity causing the participant l to become more impulsive and emotional. This shows just how helpful that brain scans can be in everyday life as raine managed to get NGRI’s reduced sentences from his research

Question 6

Evaluate a strength of a PET scan

Answer 6

P- Can witness the brain in action
E- E.g. hippocampus active during journey recall
E- Work out function of areas of the brain

Question 7

Evaluate a weakness of a PET scan

Answer 7

P- Low validity
E- Scanners restrict movement so activity can only be studied in passive bodily states
E- Difficult to isolate the different brain areas functioning

Question 8

How do fMRI scans differ from MRI scans?

Answer 8

MRI scans image anatomical structure whereas fMRI image metabolic function

Question 9

How do fMRI scans work?

Answer 9

• Uses magnetic imaging
• Head is placed inside a large, powerful electromagnet
• Required to carry out a task consisting of periods of activity and periods of rest
• Nuclei within hydrogen molecules in water align themselves with the direction of the magnetic field
• As neural activity increases in the brain, blood flow increases in the active areas to keep up with the demand for oxygen
• The scanner sends the information to a computer
• Able to create a map of activation to show changing levels of neural activity in different brain areas as tasks are being completed

Question 10

Evaluate a strength of a fMRI scan

Answer 10

P- Safest method
E- Doesn’t use radiation
E- Not at risk of obtaining health issues, e.g. cancer, so is ethical

Question 11

Evaluate a weakness of a fMRI scan

Answer 11

P- Unsuitable for some patients
E- Have to remain completely still for the duration
E- Difficult for some people, e.g. children, elderly etc