Understanding Coupling and Synchronization in EEG of Epileptic Discharge Using Recurrence Plots with Varying Threshold

The emergence of epileptic seizure is not clearly understood and the phenomenon is characterized by a synchronous discharge of large population of neurons. The property of recurrence of dynamical systems is utilized in understanding the synchronicity of epileptic discharge. The synchronization index is evaluated from the recurrence distribution of phase space. This study presents the variations in the recurrence dynamics by varying the threshold. The results of synchronization index indicate that the enhanced synchronicity is observed during seizure and decreases to near baseline level following seizure. Therefore the recurrence can be used in measuring the state of synchronicity in neuronal ensemble in various traits of brain function.