Perspectives on Detecting the Effective Brain Connectivity — The AR Approach
How brain areas communicate during different mental tasks or under specific conditions has not yet been clarified. This study contributes to the understanding of communication between brain areas by analyzing the methods that reveal cerebral interactions and brain influences using data from Event-Related Potentials (ERP), Functional Magnetic Resonance Imaging (fMRI), electroencephalogram (EEG), and Cerebral Blood Flow (CBF). To investigate effective connectivity in the brain, the autoregressive time variant (tvAR) models are used. The investigation of the effective connectivity included the analyses by means of time variant Granger Causality Index, of time variant Partial Directed Coherence, and of partial correlation. The second objective of the study was the application of the methods to composed physiological data. The methods are applied to examine change in the physiological control system, by extracting the directed connections between the heart rate, blood pressure, and respiratory signal.
Keywords: Time variant autroregressive models, EEG, Granger causality, signal processing, partial directed coherence, partial correlation.