How early maternal separation and juvenile experience with pups affect maternal behavior and emotionality in adult postpartum rats

Abstract

To assess the effects of preweaning and juvenile experiences on adult maternal behavior, two experiments were completed. In Experiment 1, pups were separated for long periods or short periods or were left undisturbed over the 1st week. Following weaning, the rats were exposed to foster pups over a 5-day period or were left undisturbed. There were no effects of early experience on juvenile behavior. In adult postpartum maternal tests, short separations reduced latencies to express maternal behaviors, whereas long separations combined with juvenile exposure to pups increased latencies. In Experiment 2, pups were separated for long periods or were left undisturbed over the 1st week. Following weaning, the rats were exposed to foster pups for 4 days or 8 days or were left undisturbed. Long separation retarded maternal responding in juvenile animals but had no effect on the adults. Four days of juvenile experience had negative effects on adult behavior, whereas 8 days did not have an effect.

Differential Effects of Short- and Long-Term Early Maternal Separation on Subsequent Maternal Behavior in Rats

“…In a more recent study, although lactating females displayed increased pup-directed behavior (e.g., pup-licking) and decreased non-pup-directed behavior (e.g., burrowing) immediately following reunion of isolated (1-hr/day) and handled (5-10 min/day) litters, those females exposed to isolation as neonates did not show this pattern toward their own isolated litters (Kosten & Kehoe, 2010). On the other hand, 3 hr of daily maternal separation had few negative effects on later maternal behavior, and 15 min of daily separation enhanced later maternal behavior in adult rats (Rees & Fleming, 2001). Such differences in maternal responsiveness between studies may be explained, at least in part, by variations in duration of maternal separation, timing of the separation during development, number of separation episodes, isolation conditions, and/or choice of control group (Lehmann & Feldon, 2000).…”

Motherless rats show deficits in maternal behavior towards fostered pups

“…For instance, neonates that are separated from the maternal nest for 3 or 5 h daily show reduced maternal behaviors towards their own pups in adulthood Rees & Fleming, 2001). In our lab we have also employed a complete maternal deprivation paradigm (24 h daily).…”

Effects of early deprivation and maternal separation on pup‐directed behavior and HPA axis measures in the juvenile female rat

“…Conversely, maternal separation as well as artificial rearing decrease maternal licking and crouching behavior in adulthood; however, only artificial rearing has a robust disruptive effect on juvenile maternal behavior (Gonzalez & Fleming, 2002;Gonzalez, Lovic, Ward, Wainwright, & Fleming, 2001;Lovic et al, 2001;Rees and Fleming, 2001). Whether these effects of artificial rearing on maternal behavior are due to changes in the HPA axis remain unclear, although research has shown that artificial rearing does not affect baseline or stress-induced levels of corticosterone (Burton, Chatterjee, Chatterjee-Chakraborty, Lovic, Grella, Steiner, & Fleming, 2007;Ward, Xing, Carnide, Slivchak, & Developmental Psychobiology Wainwright, 2004).…”

“…Maternal separation disrupts adult postpartum maternal behavior (Boccia & Pedersen, 2001;Lovic et al, 2001), but has only subtle effects on juvenile maternal behavior Rees & Fleming, 2001). Whether early deprivation affects maternal behavior has not been investigated, although early deprivation transiently increases maternal behavior during maternal sensitization of the adult virgin rat (Rees & Fleming, unpublished observations) and may have the same effect on juvenile maternal behavior.…”

“…If exposed to pups, female juvenile rats will show maternal behaviors soon after weaning (Bridges, Zarrow, Goldman, & Denenberg, 1974;Brunelli, Shindledecker, & Hofer, 1985;Gray & Chesley, 1984;Oxley & Fleming, 2000;Rees & Fleming, 2001). Juvenile maternal sensitization is unlike the adult virgin sensitization in that juvenile rats show shorter latencies to become maternal (Brunelli et al, 1985;Mayer, Freeman, & Rosenblatt, 1979; which may be a result of a still developing juvenile fear and/or stress system (Numan & Insel, 2003).…”