Maternal contributions to sensory experience in the fetal and newborn rat (Rattus norvegicus).

Abstract

Using videographic analyses, we identified and quantified maternal contributions to the sensory environment of the perinatal rat (Rattus norvegicus) by analyzing, from the offspring's perspective, the dam's activities during gestation, labor, and delivery. Our observations indicate that pregnant females remain highly active during the final week of gestation, as compared with nonpregnant control animals. Exploratory movements, feeding, drinking, self-grooming, and other activities of the rat dam pitch, turn, accelerate, and expose fetuses to mechanical pressures. During parturition uterine contractions and maternal licking and handling provide vigorous tactile and vestibular stimuli to pups. Newly born pups are exposed to intense thermal stimulation, cooling rapidly to the temperature of the postnatal environment. Our results suggest that fetal and newborn rats are exposed during development to a broad range of maternally produced stimuli.

Fetal Learning About Ethanol and Later Ethanol Responsiveness: Evidence Against “Safe” Amounts of Prenatal Exposure

“…There is now a general agreement that the fetus is exposed to considerable stimulation in utero and that maternal behavior and physiology contribute significantly to fetal experience (19)(20)(21)(22)(23). Studies to assess maternal activity in the rat during pregnancy have shown that fetuses are exposed to a dynamic series of different stimuli.…”

Effects of labor contractions on catecholamine release and breathing frequency in newborn rats.

“…Following delivery, there ensued a thermal regimen mimicking the natural sequence of postpartum temperature exposures within the nest (Alberts et al, 1991;Ronca et al, 1993), which typically involves evaporative cooling immediately after delivery and rewarming when the dam gathers and begins to brood the pups. Blood was collected at 0, 5, 30, 60, 90, or 120 min postpartum (hereafter referred to as T0, T5, T30, T60, T90, and T120); thus the amount of time pups spent at a given temperature depended on the temporal condition to which they were assigned.…”

“…We also found that simulated labor contractions more than double the likelihood that pups will first attach to the mother's nipple at 2 hr postpartum (Abel, Ronca, & Alberts, 1998) under thermal conditions mimicking the rat's natal environment in the laboratory setting (Alberts, Blumberg, & Ronca, 1991). Using remote video surveillance, we have described in detail the birth process in the rat from the offspring's perspective (Ronca, Lamkin, & Alberts, 1993). Behavioral expressions of labor are present 6 hr prior to the birth of the first pup.…”

“…Our model simulates the mammalian birth process and preserves major ecological aspects of the rat's perinatal environment. In other words, we applied forms and levels of stimulation to which the perinatal rat is typically exposed during parturition and the period of early maternal care (Alberts et al, 1991;Ronca et al, 1993;Ronca & Alberts, 1994).…”

Orbital spaceflight during pregnancy shapes function of mammalian vestibular system.

“…In contrast to Earth-bound controls, we expected the flight dams to turn and rotate their bodies more frequently and in orientations that would be uncommon on Earth. The dams' behavior is biologically meaningful because their body movements create numerous episodes of angular acceleration that can be detected by fetuses and evoke responses from them (Ronca, Lamkin, & Alberts, 1993). We predicted neurovestibular and behavioral changes in offspring secondary to the pregnant dams' behavior in microgravity.…”