Melo Angel I, Lovic Vedran, Gonzalez Andrea, Madden Melissa, Sinopoli Katia, Fleming Alison S
Centro de Investigación en Reproducción Animal, Universidad Autónoma de Tlaxcala, CINVESTAV-Laboratorio Tlaxcala. Apdo. Postal 62 Tlaxcala Tlax. 90000, México.
Dev Psychobiol. 2006 Apr;48(3):209-19. doi: 10.1002/dev.20130.
Maternal and littermate (social) separation, through artificial rearing (AR), disrupts the development of subsequent maternal behavior and social learning in rats. The addition of maternal-licking-like stimulation during AR, partially reverses some of these effects. However, little is know about the role of social stimuli from littermates and nest odors during the preweaning period, in the development of the adult maternal behavior and social learning. The purpose of this study was to examine the effects of peer- and peer-and-odor rearing on the development of maternal behavior and social learning in rats. Female pups were reared with mothers (mother reared-MR) or without mothers (AR) from postnatal day (PND) 3. AR rats received three different treatments: (1) AR-CONTROL group received minimal tactile stimulation, (2) AR-ODOR females received exposure to maternal nest material inside the AR-isolation-cup environment, (3) AR-SOCIAL group was reared in the cup with maternal nest material and a conspecific of the same-age and same-sex and received additional tactile stimulation. MR females were reared by their mothers in the nest and with conspecifics. In adulthood, rats were tested for maternal behavior towards their own pups and in a social learning task. Results confirm our previous report that AR impairs performance of maternal behavior and the development of a social food preference. Furthermore, social cues from a littermate, in combination with tactile stimulation and the nest odor, reversed the negative effects of complete isolation (AR-CONTROL) on some of the above behaviors. Exposure to the odor alone also had effects on some of these olfactory-mediated behaviors. These studies indicate that social stimulation from littermates during the preweaning period, in combination with odor from the nest and tactile stimulation, contributes to the development of affiliative behaviors.
通过人工饲养（AR）使母鼠与同窝仔鼠（社交）分离，会扰乱大鼠后续母性行为和社交学习的发展。在人工饲养期间添加类似母鼠舔舐的刺激，可部分逆转其中一些影响。然而，对于断奶前同窝仔鼠的社交刺激和窝气味在成年母性行为和社交学习发展中的作用，我们知之甚少。本研究的目的是考察同伴饲养以及同伴与气味结合饲养对大鼠母性行为和社交学习发展的影响。雌性幼鼠从出生后第3天起与母鼠一起饲养（母鼠饲养-MR）或不与母鼠一起饲养（人工饲养-AR）。人工饲养的大鼠接受三种不同处理：（1）AR-对照组接受极少的触觉刺激；（2）AR-气味组的雌性大鼠在AR隔离杯环境中接触母巢材料；（3）AR-社交组在杯中与母巢材料以及同年龄、同性别的同种个体一起饲养，并接受额外的触觉刺激。MR组的雌性大鼠在巢中由母鼠和同种个体饲养。成年后，对大鼠针对自己幼崽的母性行为以及在社交学习任务中的表现进行测试。结果证实了我们之前的报告，即人工饲养会损害母性行为的表现以及社交食物偏好的发展。此外，来自同窝仔鼠的社交线索，与触觉刺激和窝气味相结合，逆转了完全隔离（AR-对照组）对上述某些行为的负面影响。仅接触气味也对其中一些嗅觉介导的行为有影响。这些研究表明，断奶前同窝仔鼠的社交刺激，与窝气味和触觉刺激相结合，有助于亲和行为的发展。
