Maturation of the cortical auditory event- related brain potentials in infancy

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, but might also have wide clinical applications. To this end, it is very important to study the normal course of ERP maturation in the same infants in a fine-graded manner, in order to obtain a normative database. The present studies therefore aimed at investigating 1) the age-related obligatory ERP changes during the first 12 months of age; 2) the infantile ERP correlates of stimulus features (pitch, duration); 3) the maturation of the central processing of stimulus change from birth to 12 months of age. The results indicated, first, that all ERP peaks observable at the age of 12 months and later in childhood (the P150, N250, P350, and N450) could be identified as early as at birth. The second major finding was that the infant’s ERP was significantly affected by the duration of auditory stimuli at the latency zone of the N250. The pattern of the duration-