Revealing changes in directed interstructural couplings at limbic seizures, induced by injection of CB1 receptor antagonist using nonlinear Granger causality method

Epileptic seizures are considered to result from abnormal interactions between brain structures. Temporal lobe epilepsy, the most frequent and pharmacoresistant form of epilepsy, is associated with pronounced changes in brain connectivity. In the present study we successfully used nonlinear adapted time varying Granger causality to reveal changes in connectivity (increase and decrease) between hippocampus, thalamus, midbrain and frontal cortex, accompanying limbic seizures developed due to chronic treatment with CB1 receptor antagonist SLV326. In addition, two stages of the seizure were detected with time-frequency analysis, with the high (15-20 Hz) frequency being dominant during the first stage and the low (2 Hz) frequency being dominant during the second stage, with this division being partly in agreement with results of coupling analysis.