Capacity of fetus for memory and learning

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This study was conducted in order to investigate whether the newborn mice remember the taste/odor stimulus directly injected into the amniotic fluid in their fetal period.The 451 newborn pups from Slc;ICR female mice were used and 8 subject groups was formed as follows: 3 experimental groups (VV, ApAp, and SS), 3 control groups (NV, NAp, and NS), sham operation group (Sham), and intact group (NN). The VV group, ApAp group, and SS group received vanilla, apple juice, and saline in fetal period and was tested the preference to vanilla, apple juice, and saline after birth, respectively. The NV group, NAp group, and NS,group was not received any stimulus in fetal period, but was tested the preference to vanilla, apple juice,,and saline after birth, respectively.On Day 16 of gestation, 0.025ml of taste/odor stimulus (vanilla, apple juice, or saline) was injected into the amniotic sac adjacent to the nose-mouth area of each fetus. On day 2 after birth, nipples of the anesthetized mother were coated with vanilla, apple juice or saline, and the stimulus preference of the newborn pups were tested in the experimental groups and control groups.The most remarkable results were obtained in the NV and VV groups. The NV pups avoided the vanilla coated nipples when their preference to vanilla was tested. It shows that vanilla is an aversive stimulus for the newborn pups. The VV pups, exposed to the vanilla in fetal period, however, did not avoid them. Apple juice and saline had no effect on the preference of pups to them. These results suggest that the fetuses can memorize the taste/odor change (especially in aversive stimulus) in the amniotic fluid, and that the prenatal environment in utero plays a very important role for the development of fetal memory.