Theoretical physics / Elméleti fizika

Somogyvári Zoltán (Wigner RMI): Determination of temporal structure of causal effects in time series

Europe/Budapest
Tanacsterem

Tanacsterem

Description
Identification of causal relationships between time series is one of the most important question in many branches of science. The core of this question is that how we can distinguish between common cause, unidirectional direct causal effects or the circular causality which can not be assessed by the different forms of correlation. The most widely used and Nobel-price awarded method, the Granger-causality uses linear regression models, assumes weak connections and become ambiguous in case of circular causality. George Sugihara et al. in 2012 introduced a new framework for causality analysis, using the phase-space reconstruction based on the Takens-theorem. It was demonstrated that the new method is be able to distinguish between the correlation and causality even in the circular case however the new method provides information only on the existence of a causal relation. We extended the Sugihara method in order to identify temporal delays in causal effects and made it applicable for electric potential recordings in the brain. In the talk, we present the background of causality analysis and the new method, as well as results on simulated coupled chaotic systems.