In this letter we discuss use of Granger causality to the analyze systems of
coupled circular variables, by modifying a recently proposed method for
multivariate analysis of causality. We show the application of the proposed
approach on several Kuramoto systems, in particular one living on networks
built by preferential attachment and a model for the transition from deeply to
lightly anaesthetized states. Granger causalities describe the flow of
information among variables.Comment: 4 pages, 5 figure