Body odors of newborns activate neuronal regions associated with reward in women
Résumé
Olfactory signals are prime mediators of mother-infant bonding in. mammals, and they have been shown to be linked with maternal. attitudes and behavior in our own species as well. Human mothers. are indeed highly attentive to their infants odor cues, but although. we have good understanding of the neuronal network supporting. mother-infant olfactory recognition in various mammals, to date. no such information exists for humans. The present study is a first attempt at delineating the neural. network underlying the processing of infant odor properties by. women. Using functional magnetic resonance imaging (fMRI),. we measured the pattern of cerebral activation of first-time mothers. and nulliparous women while smelling the body odor of unfamiliar. 2 day-old newborn infants. Both groups of participants did. perceive infants body odor as equally pleasant, intense, and familiar. Smelling an infant’s body odor provoked significant activity in. neostriatal areas, the hippocampus, and the insular cortex. The. cerebral activation of mothers and nulliparous women differed,. however, within these areas. Mothers demonstrated higher activity. bilaterally within the caudate nuclei compared to nulliparous. women. This study reveals that body odors from 2 day-old newborns produce. activation in reward-related cerebral areas in women, regardless. of their maternal status. Recent mothers show, however,. stronger infant odor-elicited activation in the caudate nucleus, suggesting. that they may be more sensitive than nulliparous women to. the reinforcing value of their offspring odor qualities. This suggests. that body odors might act as a catalyst for reward learning mechanisms. involved in the development of bonding.