EEG synchronization characteristics of functional connectivity and complex network properties of memory maintenance in the delta and theta frequency bands.

Task-dependent changes of nonlinear-linear synchronization features and graph theoretical properties of the delta and theta frequencies were analyzed in the present EEG study that were related to episodic memory maintenance processes. Synchronization was found to increase with respect to both the delta and theta bands within the frontal and parietal areas and also between these regions. Results of graph theoretical analysis indicated a task-related shift towards small-world network topology in the theta band.