Maternal Odor Reduces the Neural Response to Fearful Faces in Human Infants

Maternal odor is known to play an important role in mother-infant-interaction in many altricial species such as rodents. However, we only know very little about its role in early human development. The present study therefore investigated the impact of maternal odor on infant brain responses to emotional expression. We recorded the electroencephalographic (EEG) signal of seven-month-old infants watching happy and fearful faces. Infants in two control groups exposed to no specific odor (control 1) or the odor of a different infant’s mother (control 2) showed the expected EEG fear response. Crucially, this response was markedly absent in the experimental group exposed to their mother’s odor. Thus, infants respond differently to fear signals in the presence of maternal odor. Our data therefore suggest that maternal odor can be a strong modulator of social perception in human infants.

Developing a neurobehavioral animal model of poverty: Drawing cross-species connections between environments of scarcity-adversity, parenting quality, and infant outcome

Children reared in impoverished environments are at risk for enduring psychological and physical health problems. Mechanisms by which poverty affects development, however, remain unclear. To explore one potential mechanism of poverty's impact on social–emotional and cognitive development, an experimental examination of a rodent model of scarcity-adversity was conducted and compared to results from a longitudinal study of human infants and families followed from birth (N = 1,292) who faced high levels of poverty-related scarcity-adversity. Cross-species results supported the hypothesis that altered caregiving is one pathway by which poverty adversely impacts development. Rodent mothers assigned to the scarcity-adversity condition exhibited decreased sensitive parenting and increased negative parenting relative to mothers assigned to the control condition. Furthermore, scarcity-adversity reared pups exhibited decreased developmental competence as indicated by disrupted nipple attachment, distress vocalization when in physical contact with an anesthetized mother, and reduced preference for maternal odor with corresponding changes in brain activation. Human results indicated that scarcity-adversity was inversely correlated with sensitive parenting and positively correlated with negative parenting, and that parenting fully mediated the association of poverty-related risk with infant indicators of developmental competence. Findings are discussed from the perspective of the usefulness of bidirectional–translational research to inform interventions for at-risk families.

A new model as an early life manipulation: Fake mother

IntroductionEarly life stressful events cause long-term neural changes that are associated with psychiatric disorders.ObjectiveEarly life manipulations focus on commonly the impact of remaining separate from the mother in a specific period of time. The maternal odor is required for pups to approach the mother for nursing. What happens when there is a mother that smell like a real mother but does not take care her own pups?AimTo investigate the fake mother effects on adult rat's behavioral changes, NMDR2B protein level changes in prefrontal cortex and hippocampus.MethodsWistar rats were used. Fake mother (n:13), early handling (n:12), maternal separation (n:14) and control (n:12) were the study groups. A fake mother is an object that smells like a real dam. When the real mother is separated from own pups fake mother stays with the pups for an hour. Manipulations were made during the postnatal first 14 days. Behavioral tests (social interaction test, elevated plus maze, novel object recognition test) were made between postnatal 62 and 78 days. NMDAR2B protein levels in prefrontal cortex and hippocampus were evaluated by using ELISA at postnatal 78 days.ResultsIn social interaction test, fake mother group exhibited less social behavior and more aggressive behavior than the other groups. Their long-term memory functions were the lowest. NMDAR2B protein levels in the hippocampus increased in rats that exposed to early stressful life events.ConclusionThese results support that being raised by fake mother increases aggressive behavior and decrease social behavior in adulthood.Disclosure of interestThe authors have not supplied their declaration of competing interest.