Social aversive stimuli presented to the mother produce the precocious expression of fear in rat pups

Abstract

During the stress hypo-responsive period, rat pups do not display fear responses toward adult males, yet they exhibit distress behavior in isolation. Since the mother modulates her offspring's affective development, we hypothesized that by altering the mother's behavior, a prolonged stressful situation would modify the ontogeny of the fear responses and distress behaviors in pups. Therefore, we repeatedly exposed the mother-litter dyad to different socially stressful stimuli and subsequently evaluated in 8-day-old pups their fear responses toward an anesthetized male, as well as their distress behavior in isolation. Our results show that repeated exposure to unfamiliar males and females, which altered maternal behavior by eliciting aggression in the mother, was associated with the precocious fear responses in pups, though without altering their distress behavior in isolation. We propose that the mother, as the principal mediator of environmental influences, provokes the precocious expression of fear in pups through alterations in her maternal behavior.

Environmental Intervention as a Therapy for Adverse Programming by Ancestral Stress

“…The indication that ancestral stress enhances the vulnerability to hyperactive and anxiety-like behaviours agrees with findings made in prenatally stressed animals45464748. Our results also validate those of other studies that found precocious development of fear-related behaviours in rat pups after maternal stress49 and CORT exposure50. A possible mechanism is that stress-induced hormonal imbalance prior to pubescence may accelerate testicular development, thus increasing the brain’s exposure to androgens during development followed by a decline in testosterone during adulthood51.…”

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

“…Rodent work indicates that infant offspring can acquire fear to a conditioned stimulus vicariously through their mother (Chang & Debiec, ; Debiec & Sullivan, ). Furthermore, exposing mothers to a socially aversive stimulus (i.e., adult male intruder) in the presence of their infant offspring leads to the precocious expression of fear to that stimulus in the offspring (Zuluaga, Agrati, Uriarte, & Ferreira, ). Given that offspring of previously stressed mothers exhibit atypical affective development (i.e., precocious fear behavior; Kan et al, ), it is possible that displays of heightened fear in mothers following maternal‐separation may play a role in those findings.…”

Affective changes during the postpartum period: Influences of genetic and experiential factors

“…For most mammals, especially during the neonatal period, the mother is the main source of stimulation. As such, different amounts or types of maternal care received modify many aspects of the neurobehavioral development (Kaffman and Meaney, 2007;Ladd et al, 2000;Loman and Gunnar, 2010;Zuluaga et al, 2014).…”