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Newborns have a functioning sense of smell at birth, which appears to be highly significant for feeding and bonding. Still, little is known about the cerebral odor processing in this… Click to show full abstract
Newborns have a functioning sense of smell at birth, which appears to be highly significant for feeding and bonding. Still, little is known about the cerebral odor processing in this age group. Studies of olfactory function relied mostly on behavioral, autonomic and facial responses of infants. AIM The aim of the present study was to investigate central odor processing in infants focusing on EEG-derived responses to biologically significant odors, namely a food and a non-food odor. MATERIAL AND METHODS A total of 21 term-born, healthy infants participated (11 boys, 10 girls; age range 2-9 months, mean 5.3±2.2 months). Odor stimuli were presented using a computer controlled olfactometer. Breast milk was used as food odor. Farnesol was presented as a non-food odor. In addition, odorless air was used as a control stimulus. Each stimulus was presented 30 times for 1 second with an inter-stimulus-interval of 20 seconds. EEG was recorded from 9 electrodes and analyzed in the frequency domain. RESULTS EEG amplitudes in the delta frequency band differed significantly after presentation of food (breast milk) odor in comparison to the control condition and the non-food odor (farnesol). These changes were observed at the frontal recording positions. CONCLUSION The present study indicates that central odor processing differs between a food and a non-food odor in infants. Results are interpreted in terms of focused attention towards a physiologically relevant odor (breast milk) suggesting that olfactory stimuli are of specific significance in this age group.