Premature infants spend critical periods of early development in neonatal intensive care. The stress and pain experienced as part of early medical care can lead to the disorganization of infant behaviour or physiologic states, which may reflect risk for adverse neurodevelopment. Research links early stress to changes in brain stress circuits and heart rate regulation and follow-up studies show that high-risk premature infants have a high incidence of attention related deficits. Julianne Petrie-Thomas is examining the complex relationships between behavioural and physiological regulation of attention by studying focused attention and patterns of heart rate in premature infants at 8-months compared with term-born controls. As the infant’s interactions with its mother play an essential role in the regulation of behavioural as well as internal physiological systems, she is also studying the effects of maternal-infant interaction on infants’ behaviour and physiology. The findings could fill major gaps in understanding of how attention problems develop in premature infants and lead to interventions that significantly improve the developmental outcomes of these vulnerable babies.