fMRI Flashcards
1
Q
What is the BOLD effect?
A
Blood Oxygen Level Dependent effect
Hb diamagnetic whilst Hb02 paramagnetic
=> T2* reduced by deoxygenated blood
Use T2w GRE w EPI readout
2
Q
Graph of BOLD response vs time
A
Activity => O2 down
-1% over 3 s response time
Vasodilation + increased flow => O2 up
through 0 up to +1% change
3
Q
Three fMRI task paradigms
A
Subtraction IM1-IM2
Parametric aAAAa
Conjugation A+B+C vs D+B+E
4
Q
Three fMRI study designs
A
Block
Event-related
Resting state
5
Q
Three fMRI pre-processing steps, and three processing steps
A
motion correction
signal drift correction
distortion correction
general linear model
p value threshold map
overlay onto anatomical map
