Differentiation of motor and automatic function control during different sleep states appears early in human ontogeny. Time of first appearance, magnitude of between-state differences and modifications with age depend on which particular parameters are considered. For some parameters, significant between-state differences appear at 31 weeks conceptional age (wk CA). For nearly all parameters, this difference is clear from 35 wk CA onwards. The analysis presented herein is based on studies of body movements, spontaneous skin potential responses, respiratory characteristics, heart rate and heart rate variability, and correlations between different functions. It examines clinically and neurologically normal premature and full-term neonates of 28-41 wk CA.