Dear list,
normally a PPI analysis aims to investigate changes in functional
connectivity between a seed and other brain regions as function of a
psychological variable with discrete levels (like attention: yes/no).
I'm currently working on a data set in which I would like to study
changes in connectivity to a seed region as a function of task
performance measured in each trial. Therefore, I was wondering whether
it is possible to perform a "parametric" PPI, in which the VOI time
course of the seed region (here: right TPJ) is modulated by the trial
performance score?
I attached a figure showing an example of what I mean. It shows the VOI
time course in the right TPJ, the modulator, and the resulting
interaction. Here, the modualor is the mean-centered performance score
in task blocks (60 sec duration). It is set to zero in phases not
belonging to the task blocks.
- Has such an approach ever been used? If so, could you provide me with
some references?
- Would this be a "valid" way of analyzing my data?
- Are there other/better possibilities of performing such an analysis? A
DCM-like approach is not really possible, since I do not have a strong
anatomical hypothesis on a specific target region. Instead, several
target regions seem plausible.
Thanks a lot!
Sebastian
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