Granger causality in brain
connectivity studies using functional Magnetic
Resonance Imaging (fMRI) data
Alard
Roebroeck and Rainer Goebel, Faculty of Psychology and
Neuroscience, Maastricht University
This talk will discuss the application of Granger causality to fMRI
data in
the form of Granger causality mapping (GCM), which is used to explore
directed influences between neuronal populations (effective
connectivity) in
fMRI data. The method does not rely on a priori specification of a
model
that contains pre-selected regions and connections between them. This
distinguishes it from other fMRI effective connectivity approaches that
aim
at testing or contrasting specific hypotheses about neuronal
interactions.
Instead, GCM relies on the Granger causality concept to define the
existence
and direction of influence from temporal information in the data. The
problems of limited temporal resolution in fMRI, and the hemodynamic
source
of the signal that makes direct interpretation of fMRI Granger
causality as
neuronal influence difficult, will be discussed.
[
NIPS 2009 Causality and Time Series
Mini-Symposium]