Newborn infants must rapidly adjust their physiology and behavior to the specific demands of the novel postnatal environment. This adaptation depends, at least in part, on the infant's ability to learn from experiences. We report here that infants exhibit learning even while asleep. Bioelectrical activity from face and scalp electrodes was recorded from neonates during an eye movement conditioning procedure in which a tone was followed by a puff of air to the eye. Sleeping newborns rapidly learned the predictive relationship between the tone and the puff. Additionally, in the latter part of training, these infants exhibited a frontally maximum positive EEG slow wave possibly reflecting memory updating. As newborns spend most of their time sleeping, the ability to learn about external stimuli in the postnatal environment during nonawake states may be crucial for rapid adaptation and infant survival. Furthermore, because eyelid conditioning reflects functional cerebellar circuitry, this method potentially offers a unique approach for early identification of infants at risk for a range of developmental disorders including autism and dyslexia.EEG | eyelid conditioning | neonate D uring the first days of life, awake infants are capable of learning associations between oral motor patterns and altered milk flow (1) and can learn to alter sucking to produce a variety of reinforcers, including milk (2), their mother's voice (3, 4), or a sweet-tasting solution (5). Cross-sensory associative learning also has been demonstrated in awake neonates using paired auditory and visual stimuli (6, 7). Furthermore, awake newborns show Pavlovian conditioning to tactile (8) and taste stimuli (9, 10), as well as eyelid conditioning to paired auditory and tactile stimuli (11). These early adaptations to the postnatal environment have been well documented in awake infants, but as newborns spend the vast majority of their time asleep, the need and capacity to learn may not be confined to states of wakefulness.Even while asleep, neonates are able to process external information actively. Scalp recordings of brain activity in sleeping neonates have demonstrated their capacity to differentiate between two sounds (12-14), indicating that infants are forming representations of specific stimuli and distinguishing between those stimuli during sleep. We report here that sleeping neonates not only process information about individual events, but also learn about relationships between them.To investigate whether neonates can learn during sleep, we attempted to condition an eye movement response in 1-to 2-dayold infants while they slept. All infants were fed immediately before testing to increase the likelihood they would sleep through the entire procedure. Sleep status was confirmed using behavioral observations in conjunction with heart rate variability patterns, respiratory regularity, and video scoring of the infants' faces. Infants were videotaped while exposed to tones and puffs of air directed at the eyelid. In the experimental group, tones w...
