The objective of the study is to explore interactions between cortical and autonomic functions in the first weeks of postnatal life. We investigated the behaviour of one-channel electroencephalogram (EEG) patterns and heart rate (HR) dynamics in preterm infants. In a group of 15 healthy preterm infants with a mean conceptional age (CA) of 36 weeks and a mean postnatal age of 17.5 days simultaneous registration of amplitude integrated EEG (aEEG) and HR pattern was performed during interfeeding intervals. Periods with a discontinuous EEG activity and a low heart-rate variability (HRV) were selected for further processing and averaging. It was found that spontaneous activity transients (SATs) or slow wave EEG bursts during "Trace alternant" (TA) can be accompanied by an HR acceleration of 1-2% (mean: 1.9, range: 0.6-3.5 beats/min) lasting approximately 5s (mean, range: 3.6-7.1s). The aim of the study is to give evidence of a coherent behaviour of EEG bursts and HR in the developing nervous system of preterm infants.