methods of studying brain structure and function Flashcards
phrenology - historical
bulges and dips on the skull correspond to brain areas and specific behaviours
staining techniques
cell body stains - reveals cells in brain tissue
myelin stains - bundles of myelinated nerve fibres
membrane stains - reveals dendrites and there spines
histochemical techniques
locate specific neurons and neurotransmitters
- does not tell living brain
immunocytochemical techniques
take advantange of normal immune reactions
- does not tell living brain
CT/CAT scans
living brain
x-ray passes through head and image is produced
whiter = denser - good for diagnosis on tumours
MRI - magnetic resonance imaging
uses magnet to observe radiation from hydrogen atoms which are present in all cells at diff concerntrations
FMRI - frontal magnetic resonance imaging
adds to MRI as shows function
measures metabolic activity as active brain areas consume more oxygen
PET scan - positron emission tomography
glucose injected into patient and active cells take this up - shows which areas are active and which areas are healthy or in decline
advantages of brain imaging
non-invasive
good spatial resolution
can be used to compare
disadvantages of brain imaging
risk from xrays and radiation
poor temp resolution
noisy, scary, claustrophobic
expensive in time and money
what does measuring electrical activity tell us?
which structures are used for particular functions
measuring brain activity with microelectrodes
implanted in brain to monitor activity of neurons
records very precise activity
but highly invasive
measuring brain activity with macroelectrodes
EEG - attach to scalp in areas of expected activity and neutral areas
see diff between active and neural electrodes measured
EEG waves
beta - actively attending to events and aware
alpha - awake but not processing, relaxed
theta - light sleep
delta - deep sleep
advantages of macroelectrodes (EEG)
non-invasive
can differentiate between different conditions and behavioural states
disadvantages of macroelectrodes (EEG)
time consuming, labour intensive, lots of equipment needed
requires high levels of experience
averaging does not allow to establish activity in specific region or behaviours
experimental brain damage
controlled and localised damage to specific areas
if behaviour changes then damaged area is involved
problems with experimental brain damage
ETHICS
brain is interconnected so damage at one site may effect function of another
artificial damage vs natural damage
using SNS to measure brain activity
HR and blood pressure
using galvanic skin response to measure brain activity
activation of SNS increases sweat levels
using endocrine system to measure brain activity
hormones sampled in saliva and blood and urine etc
