BRAIN SCANNING TECHNIQUES Flashcards
What is a brain scanning technique?
Neuroscientific methods used to view the structure and activity of the brain - helps researchers and doctors to understand functions, damage and abnormalities
Three main brain scanning techniques
- CAT
- PET
- fMRI
What is a CAT scan?
Uses x-rays to take cross-sectional images of brain creating a detailed 3D image of structure
What does a CAT scan show?
- structural abnormalities eg. Tumour, bleeding
- brain injuries
- swelling
Is a CAT scan structural or functional?
Structural - shows physical structure not activity
What are the strengths of a CAT scan?
- quick and non invasive
- Good for diagnosing brain injuries or tumours
- helps doctors plan procedures
- more detailed than standard x-rays
What are the weaknesses of CAT scans?
- uses radiation (x-rays) so not suitable for repeated use
- no info about brain activity
- less detailed than fMRI
What is a PET scan?
Involves injecting radioactive glucose tracer to measure metabolic activity in brain
What does a PET scan show?
- active areas of brain ( more glucose = more activity )
- functional abnormalities linked to disorders like Alzheimer’s or schizophrenia
- used to study neurotransmitter activity
Is a PET scan structural or functional?
Functional - shows how brain is working, not just how it looks
What are the strengths of a PET scan?
- shows real time brain activity
- biological activity can be linked to behaviour
- useful in diagnosing diseases like Parkinson’s, Alzheimer’s
- useful for psychological research into neurotransmitters and metabolism
What are the weaknesses of PET scans?
- invasive!! involves radioactive injection
- expensive
- low resolution compared to fMRI so sometimes results not easy to interpret
- limited usage due to radiation
What are ethical issues linked to PET scans?
- exposure to radiation
- may cause discomfort/anxiety
- requires informed consent , especially in patients with mental illness
What is an fMRI scan?
Measures brain activity by detecting changes in blood oxygenation and flow (more oxygen = more active area)
What does an fMRI show?
- both structure and activity of the brain
- which areas are active during specific tasks or stimuli eg. Emotions, decision making
Is an fMRI structural or functional?
Both - shows high resolution images of brain structure and functional activity
What are strengths of fMRI scans?
- non invasive and no radiation
- high spatial resolution
- shows both structure and real time activity
- suitable for repeated research use
What are the weaknesses of fMRI scans?
- expensive
- requires patients to stay very still ( may be a problem for some people eg. Children so limits use)
- around 5 sec lag between brain activity and image appearing on screen so can cause problems when trying to interpret info
- measures correlation not cause
Which brain scan has the best spatial resolution?
fMRI - provides most detailed images of both structure and function
Which scan is best for detecting brain activity?
fMRI -also PET but fMRI is safer
Which brain scan is best for identifying structural damage?
CAT scan - fast and useful for detecting injuries, tumours , bleeding
Which brain scan in invasive?
PET scan - requires radioactive glucose injection
Which scan is most expensive ?
fMRI - due to powerful magnets and high resolution images
Which brain scan is safest for repeated use?
fMRI - no radiation and non invasive , so ideal for research and long term use
What are real world applications of brain scans in psychology?
- identifying neurological disorders (eg. Alzheimer’s , epilepsy)
- supporting localisation of brain function
- supporting biological explanations (eg. Aggression , schizophrenia)
- used in legal settings to assess damage
How have brain scans supported localisation of function?
fMRI studies show specific brain areas become active during tasks
Eg. Broca’s area for speech supporting localisation theory
How have brain scans supported biological treatments?
PET and fMRI scans help neurotransmitter involvement and track effectiveness of medication eg. Dopamine in schizophrenia
What are ethical issues with brain scanning in research?
- informed consent especially in vulnerable people
- incidental findings of unrelated issue eg. Tumour
- exposure to radiation
What are the limitations of interpretations brain scans?
- activity doesn’t mean cause
- Brain is complex do activity in one area may not explain behaviour
- false positives/negatives are possible
Why are brain scans useful in psychological research?
Provide scientific objective data which helps to
- understand brain-behaviour relationships
- support biological theories
- diagnose and treat mental health conditions
