BIOLOGICAL brain scanning techniques

Question 1

which techniques aer functional and which are structural

Answer 1

structural - CAT/CT
functional - PET and fMRI

Question 2

how is an image obtained when using a CAT/CT scan

Answer 2

X ray images of slices of the brain
used individually or put together to form a 3D image

Question 3

how is an image obtained using a PET scan

Answer 3

• radioactive tracer mixed wiht glucose is injected
• glucose is used up where there’s a lot of activity
• tracer decays and releases positrons

Question 4

how is an image obtained using an fMRI scan

Answer 4

• placed in a scanner wiht strong magnetic field
• causes nuclei in hydrogen molecules to spini
• produces a detailed image of different areas

Question 5

why are CAT/CT used in psychology

Answer 5

• to establish sizes of brain regions
• to identify lesions resulting in loss of neurons

Question 6

why are PET scans used in psychology

Answer 6

• to establish levels of activity
• e.g. prefrontal, amygdala links to aggression

Question 7

why are fMRI used in psychology

Answer 7

• measure emotional resonses in relation to tasks whilts in the scanner

Question 8

what is the difference between normal MRIs and fMRIs

Answer 8

MRIs - look at soft tissue, organ function and blood flow
fMRIs - only the brain

Question 9

2 strengths and 2 weaknesses of CAT/CT scans

Answer 9

• STRENGTH - gives detailed 3D images for different angles of the brain (before this, psychologists were reliant on post-mortem)
• STRENGTH - ordinarily non-invasive and painless, dye could be but only to an extent
• WEAKNESS - only provides a still image, MRIs better for certain issues, CT=skull fractures
• WEAKNESS - radiation from X rays should be kept to a minimum due to ethical issues

Question 10

2 strengths and two weaknesses on PET scans

Answer 10

• STRENGTH - allows us to study neurotransmitters due to high sensetivity of detection (allows us to study aspects of the brain)
• STRENGTH - tested for reliability by repeating scans, found to be reliable
• WEAKNESS - measures brain functioning not at rest, no baseline measure available - cant compare
• WEAKNESS - only locate generalised areas of activity, hard to pinpoint exact areas so hard to link specific areas to behaviours

Question 11

2 strengths and two weaknesses of fMRIs

Answer 11

• STRENGTH - safer than other scans e.g. PET as no invasion, radiation - uses magnetic field instead
• STRENGTH - produces higher resolution and detection of changes in blood flow - very precise
• WEAKNESS - cannot measure the brain at rest, no baseline measurment - can’t pin point actual functioning of specific areas
• WEAKNESS - cannot look at actual receptors of neurotransmitters, but PET scans can