I've red a lot of documentation and tutorial on-line but I can't understand
very well about fmri plots.
I've a 2x2 factorial event-related fMRI design, canonical hrf and time and
dispersion derivatives. I use spm2.
A) When I set: Plot -> Contrast estimates and 90% C.l. -> Effects of
interest -> attrib -> yLim 0 100, Do I see the percent signal change
relative to the whole brain mean signal for each condition? Is the raw or
filtered signal? And what the height and the sign (+/-) of the canonical hrf
bars tell me? And the height and the sign (+/-) of the time derivative bars?
And the height and the sign (+/-) of the dispersion derivative bars?
B) When I set: Plot -> Fitted responses -> choose an event -> adjusted ->
scan or time, What I see or which is the unit of measurement on the y-axis?
Each red dot rapresents one scan?
C) When I set: Plot -> Evented-related responses -> choose an event ->
fitted response and adjustaed data,What I see or which is the unit of
measurement on the y-axis? What is peristimulus time (I've only a vague
idea)? Canonical hrf and its derivatives are collapsed into one function?
D) When I set: Plot -> Evented-related responses -> choose an event ->
fitted response and 90% C.l., Do I see the sum of each basis function
multiplied by its parameter estimate so canonical hrf and its derivatives
are collapsed? Which is the unit of measurement on the y-axis?
E) When I set: Plot -> Evented-related responses -> choose an event ->
fitted response and PSTH, What means the plot shows the mean response at
each binned time point along with standard error bars? What is each binned
time point? What rapresent the standard error bars? Which is the unit of
measurement on the y-axis? Canonical hrf and its derivatives are collapsed
into one function?
F) When I set: Plot -> Volterra-Kernels -> choose an event, I see 1str order
Volterra Kernel, is this picture useful? What is rapresented? Which is the
unit of measurement on the y-axis?
Thank you.
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