Day 24_Goldstein Lecture What is Development

However the experiments we report here differ from

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Unformatted text preview: , 1963; Tinklepaugh & Hartman, 1930). However, the experiments we report here differ from previous work in the rat in two important respects. First, we used videographic techniques, which permitted us to monitor the behavior of late-gestation and parturient rat dams across the circadian cycle and to compile extensive behavioral profiles. Secondly, our analysis of dams' behaviors emphasized the offsprings' perspective and highlighted maternal contributions to the perinatal sensory environment. rearing stirring head/body grooming abdominal grooming %5f hindlimb scratching Figure 1. Behavioral activities of females that stimulate offspring in utero: Locomotion (top left), rearin g (to p center), stirring (top right), head and body grooming (bottom left), abdominal grooming (bottom center), and h indlim b scratching (bottom right). Maternal Stimulation The findings of these studies suggest that the behavior of pregnant and parturient dams generate specific tactile, vestibular, and thermal stimuli that provide sensory experience to gestating and newborn rat pups. Figure 9 is an iconographic chronology across the perinatal period of maternally produced stimuli that impinge on the offspring during gestation, parturition, and early postnatal life. As we have seen, dams are active throughout late gestation, engaging in activities similar to those of nonpregnant females. Locomotor behavior, rearing, head and body grooming, and stirring by pregnant dams during quiescent periods provide in utero accelerations. Abdominal grooming and hindlimb scratching may produce in fetuses sensations of pressure and vibration. We have not considered potentially related uterine events, such as provocative stimuli from adjacent fetuses. During parturition, repetitive uterine contractions pitch and compress fetuses at an increasingly rapid rate as delivery approaches. As each pup is born, it is licked, handled, and carried by the dam and thereby exposed to additional cutaneous and vestibular stimuli. Offspring also receive vicarious stimulation of these modalities as the dam steps or sits on pups within the nest or as she suspends or drags delivered pups that remain...
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