Auditory temporal grouping in newborn infants.

Adults normally perceive auditory scenes in terms of sound patterns emitted by concurrently active sources. Thus pattern formation is an important process of auditory object perception. The aim of the present study was to determine whether neonates group sounds by repeating pitch patterns. Standard ("S"; p=80%) and deviant tones ("D", p=20%) differing only in pitch were delivered either in a randomized order (random condition) or in a repeating SSSSD pattern (grouped condition). Both event-related brain potentials and gamma-band activity differed between the S and D tones in the random condition but not in the grouped condition. These results suggest that in the grouped condition, the S and D tones were processed as part of the same higher order regularity by the neonate auditory system. Also, for the first time, we observed oscillatory gamma-band activity in neonates, which was sensitive to infrequent pitch changes.