Ghosts of mother's past: Previous maternal stress leads to altered maternal behavior following a subsequent pregnancy in rats

Abstract

A rodent model was used to explore whether mothers that experienced a postnatal stressor in the past (i.e., daily separations from her previous litter) exhibited altered maternal behavior during a typical, subsequent rearing experience. Stress-naïve female rats were bred and then separated from their pups (maternal separation) or remained with their pups (standard-rearing). After those pups were weaned, mothers were bred again with all pups from the subsequent litter being standard-reared. In the first week of life, various maternal behaviors directed towards these subsequent offspring were observed, including levels of nursing and pup retrieval. After weaning, mothers were tested for anxiety-like behavior, as well as memory on the object-recognition and object-placement tasks. The results show that previously stressed mothers retrieve their offspring significantly faster compared to mothers with no stress history, which may reflect a more "overprotective" mothering style. No other differences on maternal care were observed. Also, while previously stressed mothers were no more anxious than control mothers, they had impaired spatial memory on the object-placement task. This was not due to a general memory impairment as mothers performed equally on the object-recognition task, suggesting that previous maternal stress has specific effects on hippocampal-dependent tasks. That is, stress exerts lasting effects on types of behavior that are proposed to be beneficial to mothers and their offspring (i.e., efficient foraging and navigation abilities). Taken together, these results provide evidence that stress has specific and persistent effects on caregivers.

Maternal care, infant fear memory retention, and the moderating role of variations in separation‐induced ultrasonic vocalizations

“…However, as discussed in Section 1, this method has previously been validated and maternal licking was the only behavior that predicted mark fading (Cavigelli et al., 2010). In addition, when dams are observed to score differences in maternal care, often only five periods that are roughly 1‐h long are selected for scoring each day (e.g., Champagne et al., 2003; Champagne & Meaney, 2006; Kan & Richardson, 2018), so the observational approach may miss variations in maternal care that occur outside of the designated scoring hours. In contrast, mark fading should indicate an average of all of the licks a pup received across the previous 24 h. Arguably, mark fading may actually be a more sensitive measure of maternal licking.…”

Maternal Experience Does Not Predict Fear Extinction and Anxiety-Like Behaviour in Primiparous Rats Post-weaning

“…The pup retrieval test occurred between 0900 h and 1300 h. The pup retrieval test was adapted from previous research (36,40). On PND8, pups were removed from the home cage and placed in a holding box for 5 min, while the mother remained in the home cage.…”

Prolonged febrile seizures induce inheritable memory deficits in rats through DNA methylation

“…In order to exclude the influence of maternal behavior on the memory performance of their offspring, 24 we next used cross-fostering. As shown in Figure S2, control pups adopted by control mothers or FSs mothers displayed similar ability of memory in Morris water maze, F I G U R E 3 DNMT mRNA activity is reasonable for the transgenerationally memory deficits after prolonged FSs.…”