Please enable JavaScript.
Coggle requires JavaScript to display documents.
Functional techniques (EEG (non-invasive
oldest fMRI technique, record…
Functional techniques
EEG
non-invasive
oldest fMRI technique
record brain activity - electrical activity on scalp surface
signal picked up by electrodes in multiple locations
Trf mathematically (inverse prob)
Adv:
cheap
somewhat portable
measure brain act at millisec scale
Disadv:
measured only at scalp surface in rel few locations
X provide accurate localisation of brain function
- Lowest spatial res
- Highest Temp res
- lowest tolerance level
- real time measurements
- records activity perp to brain
- pyramidal cells in cortical gyri
fNIRS
-
BOLD effect. blood oxygenation level depedent
differential need for red absorption spectra of oxy and de-oxy haemoglobin
indirectly measure changes in blood flow, blood oxygenation levels + blood volume
both refract +reflect light differently
limitation:1. doesn't penetrate deep into skull
- relatively small no. of sensors
adv: masure infant skull (thin and small)
low spatial res (higher than EEG)
high temporal res (not as high as EEG and MEG), > PET&fMRI
low level of tolerance
MEG
tiny magnetic fields on scalp
complementary with EEG
position head under a helmet-shaped dewar
- vacuum-filled: contains 100s of magnetometers
vat of liquid helium cool down the ultra-sensitive detectors
- highest temp res
- lowest spatial res
- medium tolerance
fMRI
magnetic properties of oxy and deoxy-haemoglobin
oxy: diamagnetic, barely magnetic
deoxy: paramagnetic, interacts more strongly with magnetic field
- indirectly measure brain activity for regional changes in magnetism
- study wide range of psychiatric and neurological disorders
- investigate healthy brain processes
highest spatial res
low temporal res: measures brain activity every few secs
(much slower than EEG & MEG)
medium level of tolerance
-
PET
high spatial (whole brain on mm scale)
lowest temporal res: 10/20 sec scales
highest tolerance, most invasive
tissue tracer conc & location - detect gamma rays emitted as byproduct of decay of the injected radioactive tracer
FDG (glucose metabolism)
F-DOPA: dist of dopamine, Parkinson's
tracers have short half-life - decay quickly - produced onsite by cyclotron - expensive
Functional Techniques
Functions
-
Det where+when neural activity in brain is associated with ability to perform a particular cognitive task
Difs in brain activation bet task variants -> isolate brain structures that are implicated in hypothesized cognitive processes
-
-