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Published on: June 27, 2014
Repeated cross-fostering affects maternal behavior and olfactory preferences in rat pups
Andrea Dulor Finkler1,2,3, Grace Violeta Espinoza Pardo2,4, Aldo Bolten Lucion1,2
1Graduate Program in Neuroscience, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
Insights
Early disruptions in mother-pup bonding, like those in adoption, can impair attachment. Rodent studies show that repeated cross-fostering (RCF) during sensitive early periods negatively impacts infant attachment and maternal care.
Area of Science:
- Neuroscience
- Developmental Psychology
- Animal Behavior
Background:
- Early mother-infant relationship disturbances impact neonatal development, leading to lifelong vulnerability.
- Institutionalized children exhibit behavioral changes linked to a lack of consistent maternal attachment.
- The effects of human adoption on early mother-infant bonding remain unclear.
Purpose of the Study:
- To investigate how adoption-like processes affect mother-infant attachment formation.
- To explore the impact of timing during sensitive developmental periods on attachment.
Main Methods:
- Utilized a repeated cross-fostering (RCF) rodent model.
- Implemented RCF during two distinct early postnatal periods: days 1-3 (early RCF) and days 9-11 (late RCF).
Main Results:
- Early RCF (postnatal days 1-3) significantly reduced pups' preference for maternal odor.
- Both early and slightly later RCF (postnatal days 9-11) decreased maternal care behaviors, including pup retrieval.
- The RCF protocol created an unstable mother-pup interaction environment.
Conclusions:
- Learned attachment to the mother is sensitive to disruptions during specific developmental periods.
- Early-life disruptions in the mother-infant relationship, particularly during sensitive phases, can have lasting effects on attachment formation.
- The timing of environmental instability is critical in modulating the impact on mother-infant bonding.
Abstract:
Disturbances in early mother-infant relationships are strongly associated with changes in the development of a number of physiological and behavioral systems in the neonate that can create a complex change in patterns of vulnerability throughout life. Institutionalized children, despite receiving adequate care, display important behavioral changes in adult life, and such changes are strongly associated with a lack of selective and consistent attachment to the maternal figure in early life. It is not yet clear how human adoption processes alter the mother-infant relationship early in life. Here, to mimic the situation of human adoption and explore the impact on the formation of attachment between the infant and a caregiver, we use a repeated cross-fostering (RCF) model in rodents in two postnatal periods, postnatal days (PND) 1 to 3 (early RCF) and 9 to 11 (late RCF). Early exposure but not late exposure to RCF reduces the pups' preference for the odor of the mother figure. Moreover, early exposure and slightly later exposure to RCF reduce maternal care and motivation in collecting the pups and bringing them to the nest. The RCF protocol creates an unstable environment for mother-pup interaction, but it seems to affect learned attachment to the mother only when it occurs during the corresponding sensitive period of development.
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