This is actually a pretty big question concerning deconvolution and the
GLM. But basically, the analysis knows what the overlap is since you
tell it which stimulus is presented when and what the shape of the HDR
looks like. The analysis then computes the amplitude of the HDR for each
condition, which is what is reported in the roi summary.
Cameron Ellis wrote:
Hi,
I am running an ROI analysis on a set of event-related data obtained
through spmhrf analysis. When I run roisumamry-sess to obtain the values
needed to calculate a percent signal change the number of estimations per
condition is 1, which makes sense since I am looking at the entire time
window. I have three conditions, however, and only three numbers
corresponding to each condition to be used in a total % signal change
calculation are generated. My question is, how are these overall values
for each condition calculated? More specifically, how are the TRs assigned
to a particular condition to calculate a value specifc to a condition when
each condition overlaps within the timewindow? Thanks in advance to anyone
who can help,
Cameron
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