Abstract: Abstract: Both methodology and experimental researches of event-related oscillations (ERO) are reviewed. Phenomena of frequency, amplitude and phase modulations at the meso- and macroscale were observed from ERO. ERO affects both average firing rate and timing pattern of neurons (microscale). As well as neuronal spike, ERO may involve in various aspects of neural information processing including coding, representation, communication and control. Combined with brain theory of dynamical cell assembly that hypotheses cognitive functions result from synchronization and/or desynchronization of oscillatory neural ensembles, investigations on ERO of cross-frequency, cross-region and cross-scale may further disclose the working principles of brain

Key words: event-related oscillations, cell assemblies, synchronization