Little is known how the brain of the newborn infant responds to the postnatal nutrition and care. No systematic studies exist in which the effects of nutritional and non-nutritional sucking on the brain activity of the infant were compared. We recorded the EEG activity of 40 infants at the ages of 0,6,12 and 24 weeks in four successive behavioral stages: while the infants were hungry and waiting for sucking, during non-nutritional and nutritional sucking, and during satiation after completed feeding. Quantitative EEG analysis was performed using occipital, parietal and central EEG channels. In the newborn infants, a significant reduction in the EEG power was found after nutritional sucking in the all EEG frequency bands studied (1-10Hz), which was paralleled by a significant behavioral alertness decline. This response decayed during the subsequent neonatal period and was completely absent at the age of 12 weeks. In 24-week-old infants, nutritional sucking was accompanied with an increase in rhythmic theta activity during which no significant alertness change took place. Non-nutritional sucking was connected with minor and non-significant effects on the EEG. We conclude that in newborn infants nutritional sucking has a direct effect on the EEG, which has a soothing character and is connected with an alertness decline. In 24-week-old infants the response to nutritional sucking is of a different type and consists of an organized, rhythmical theta activity in the EEG not directly linked with alertness change. Our findings suggest a developmental relationship between nursing and infant brain function with plausible affective and cognitive implications.
Keywords: Alertness regulation; Developmental effects; Infant EEG; Non-nutritive sucking; Nutritive sucking; Theta activity.
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