Brain scanning techniques (sakshi)

EEG (electroencephalogram)
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Terms in this set (13)
EEG (electroencephalogram)
Shows brain's electrical activity by positioning electrodes over the scalp
Advantage of EEG
Safe and painless, so good to study sleep disorders
Disadvantage of EEG
Lacks precision, able to show that a person is thinking but not whet they're thinking about
CAT scans (computerised axial tomography)
Generates cross-sectional images of the brain using a series of X-ray pictures taken from different angles. Dye injected into patient as contrast material
Advantages of CAT scans
Useful to reveal abnormal brain structures e.g. rumours, quality of images produced better than X-ray quality
Disadvantages of CAT scans
Need more radiation than X-rays so can only be used a limited number of times because dangers of too much radiation, invasive because injection so ethical issues, only provides structural info
MRI Scans (magnetic resonance imaging)
Patient exposed to powerful magnetic field that causes atoms in the brain to change their alignment. Different atoms resonate to different magnetic frequencies so structure of the brain can be seen
Advantages of MRI scans
Non invasive, shows more detail than CAT scans, no exposure to radiation so can be used repeatedly
Disadvantages of MRI scans
Takes a long time, process can cause distress e.g. claustrophobia
fMRI scans (functional MRI)
Shows structure and activity of the brain
PET scans (positron emission tomography)Radioactive glucose injected into bloodstream, brain requires glucose for active areas so more active means more glucose neededAdvantages of PET scansMeasures the brain in action, reveals chemical info that other scans can't e.g can distinguish between a benign and malignant tumour, can measure the effect of neurotransmitters on mental healthDisadvantages of PET scansCostly, injection so ethical issues, radioactive glucose so limited uses, less accurate than MRI because brain is always active