Motherless Rats Show Deficits in Maternal Behavior Towards Fostered Pups

Complete maternal deprivation ill rats, through artificial rearing (AR), produces deficits. ill subsequent maternal behavior of the offspring. These deficits are partially reversed when isolated pups are provided with additional tactile stimulation designed to simulate maternal licking (e.g., Gonzalez et of. [2001] Developmental Psychobiology, 38, 11-32). These findings highlight the importance of the earl maternal environment ill subsequent development. However:,given the possibility, that prenatal environments may, differ between AR mid maternally, reared (MR) offspring, the deficits ill the behavior of AR mothers may be driven by the characteristics of their pups derived from the effects a an altered prenatal environment. Hence differences tit the neonatal pups of AR mothers may produce the alterations ill the AR maternal behavior. To rule out this possibility, we employed a fostering paradigm where AR and MR mothers received cross-fostered mother-reared pups. AR mothers showed the same level of deficits ill maternal behavior towards MR foster pups as they, do with their own pups and these deficits were partially reversed with additional tactile stimulalion. Hence, maternal behavior deficits reported in mothers who had been reared ill isolation are due primarily, to the direct effects of the earlier experience oil mechanisms regulating their maternal behavior and not to the effects on their offspring. (C) 2009 Wiley Periodicals. Inc. Dev Psychobiol 52: 142-148, 2010.