Experimental unconfounding of age and maternal responsiveness in rodents: Prenatal cer conditioning to neonatal ultrasounds

Abstract

Prior to mating, virgin female Long-Evans Rutins norvegicus received 30 classical CER trials with shock as the UCS and either taped neonatal ultrasounds or a belltone as the CS. Additional animals were placed in groups controlling for exposure to shock, the ultrasounds, the belltone, and placement in the conditioning apparatus. Following mating and parturition mother-infant observations revealed that those mothers previously conditioned to neonatal ultrasounds spent more time in the lactation posture than did mothers from the other groups. The results suggest that naive mothers can be “primed” to exhibit greater maternal responsiveness than is characteristic of primiparous mothers.