OLFACTION AND HUMAN NEONATAL BEHAVIOR - CLINICAL IMPLICATIONS

About 1-2% of the human genome is allocated to production of receptors for the olfactory epithelium-a hint as to the possible importance of this chemical sense, which includes two anatomically distinct systems: the main olfactory system with sensory cells located in the upper par t of the nasal cavity, and the vomeronasal organ with sensory cells on the nasal septum. In adults, individual odours may influence mate pre ferences and a growing body of evidence indicates that naturally occur ring odours play an important role in the mediation of the infant's be haviour. Even foetal olfactory learning seems to occur and breast odou rs from the mother exert a pheromone-like effect at the newborn's firs t attempt to locate the nipple. Newborns are generally responsive to b reast odours produced by lactating women. Olfactory recognition may be implicated in the early stages of the mother-infant attachment proces s, when the newborns learn to recognize the own mother's unique odour signature-a process possibly facilitated by the high norepinephrine re lease and the arousal of the locus coeruleus at birth. New knowledge a bout human odour physiology may have diagnostic and therapeutic implic ations-the initiation and stabilization of breastfeeding and terminati on of apnoeic spells are mentioned as examples.