Changes in granger causality for brain connectivity depending on the concentration levels of isoflurane in rat study

Today, the developing signal processing technology leads to the medical discoveries as well as the fast and elaborate communication. Especially, neurological findings on brain connectivity are one of the interesting issues. However, in spite of the effort to study the brain connectivity by the neuroscientists and engineers, a large part of brain functions are unknown. Among them, the consciousness mechanism in the anesthesia is one hot topic in the medical fields. Although the many researchers investigate the mechanism of loss of consciousness (LOC), the feasible cause for that phenomenon is unknown. In order to evaluate the state of unconsciousness by the anesthesia, the analysis of the brain connectivity is needed. The Granger causality (GC) is one of the algorithms for extracting brain connectivity using electroencephalogram (EEG). It indicates the information flows between two different brain regions whether they are connected physically or not. In this paper, we investigate brain connectivity which is based on the GC between the brain regions of rats depending on concentration levels of isoflurane that is widely used for inhalation anesthetic in human medicine.