THE UNSURPASSED temporal resolution and connection to brain function have led to the widespread use of electroencephalography (EEG) in medical practice and scientific research [2]–[5]. The neuronal mechanism underlying EEG and the local field potentials recorded with intracranial EEG (iEEG) using intracranial electrodes (Fig. 2) are largely related to the synchronization of neuronal assemblies and their synaptic currents [6]. There is strong evidence that one of the fundamental neural mechanisms underlying normal and pathological brain activity is the synchronization of neuronal assemblies [7]–[9]. This has led to widespread interest in quantitative measures of EEG synchronization [7]. It has been noted that neuronal assemblies are characterized by the synchronous activity of their constituent neurons, and different EEG frequency components also reveal synchronies relating to different perceptual, motor, or cognitive states [7], [10]–[20].
