I'm analyzing data in SPM5 and would like to use parametric modulation to
covary out RT effects between experimental conditions. In this experimental
design there are a total of 6 experimental conditions, with RTs modeled as
From what I've gathered off of the comments posted on this matter, defining
RT's for parametric modulation at the level of each condition is
insufficient because this will only covary out trial-specific effects (i.e.
RT differences across trials WITHIN the specified condition). My question
is, in SPM5, how does one with multiple experimental conditions go about
running parametric modulation to covary out RT effects BETWEEN experimental
Additionally, opinions on whether parametric modulation is the best method
to do this, and/or suggestions regarding other options in SPM5 that may be
better, would be greatly appreciated.
Thanks in advance,
Siobhán M. Hoscheidt, M.A.
CNS Doctoral Program
Cognition & Neuroimaging Lab/ Anxiety Research Lab
University of Arizona