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
