Techniques Flashcards
x ray
not very useful except to confirm location of foreign objects
contrast x ray
use a contrast agent
MRI - Magnetic resonance imaging
radiofrequency is absorbed and emitted in a way that gives info about the tissue
fMRI- Functional magnetic resonance imaging
tune the scanner to be sensitive to blood- haemoglobin (iron)
- when haemoglobin is carrying oxygen it hides the iron so actually it picks up on the oxygenation of blood in tissue.
PET- positron emission tomography
inject radioactive tracer, use a computer to work out where it ends up.
EEG - electroenecephalogram
good temporal resolution, poor spatial resolution, good for detecting epilepsy
- event related potentials
MEG - magnetoencephalography
electrical currents in cells and white mattr induces an electrical field which can be detected
less interference from scalp but expensive
Stimulating the brain
TMS,
induces weak electrical currents in the brain
can be used to turn off parts of the brain so that their function can be assessed.
Stimulating the brain: TDCS
pass mild current through the brain
can excite or inhibit underlying brain tissue
what other things can be measured?
Brain function can be inferred from the CNS
- skin conductance.
- heart rate
- pupil dilation
- blood pressure
- heart rate
what are the rules of invasive methods (animal models)
- replacement - if another method can be used
- refinement - can it be done a better way
- reduction- smallest number of animals
Invasive methods
direct measurements
determine connectivity between structures- lesion pathways
anterograde tracer:
tracer travels forward along axon towards synapses
retrograde tracer:
travels backwards along axon
psychopharmacology
the effect of drugs on thoughts and behavioour
