Sleep is important for the growth and development of infants. There are different states that make up sleep wake cycles including quiet sleep, active sleep, and transitional sleep. The amount of time that infants spend in quiet sleep increases as they mature. There are different tools that can be used to measure sleep state including EEG, behavior, and vital signs. Recent research has looked at ways to improve sleep in infants admitted to the NICU including music and maternal voice. The investigators are interested in studying maternal scent. Maternal scent has been shown to improve infant feeding and to reduce infant crying during painful procedures. Therefore, the investigators are interested in studying how maternal scent might affect sleep wake state in infants admitted to the NICU. The investigators will observe infant behavior and use EEG and vital signs to assess sleep state in infant after they are exposed to maternal scent.