Mismatch negativity and late discriminative negativity in sleeping human newborns.

Event-related potentials were recorded from sleeping newborns to compare amplitudes and latencies of mismatch negativity (MMN) and late discriminative negativity (LDN) in active and quiet sleep stages. MMN and LDN were obtained in response to changes in semi-synthesized vowels from 20 healthy newborn infants. MMN and LDN responses were significant for both active and quiet sleep. The amplitude and latency of MMN or LDN did not differ between the sleep stages. Thus, in contrast to adult studies that show a significant drop in the MMN amplitude and an increase in the MMN latency as the sleep gets deeper, arousal stages do not seem to effect either MMN or LDN characteristics in newborns. These results suggest functional differences between infant and adult sleep.