Although brain development continues well into adolescence, the most rapid and impressive improvements in motor, cognitive, and perceptual abilities take place during the first and second years of life. The progress of the neuroimaging techniques provided the neuroanatomical data, showing that the most rapid postnatal neuroanatomical development also occurs in the first two years of age, followed by much more gradual changes. A link between the rapidly emerging psychological and behavioral functions and the underlying neural mechanisms might be provided by the electrical activity generated by neurons within the functioning brain. The electrical signals related to some external or internal event (event- related potentials, ERPs) provide real time indices of neural information processing, and can be followed throughout this crucial period of the most rapid neuroanatomical and functional development. Addressing the issue of ERP maturation during infancy is not just of academic interest, the results of these studies will help to identify potential risk factors early in development when brain is at its highest plasticity to respond to intervention.