Impact of mothers’ experience and early‐life stress on aggression and cognition in adult male mice

Abstract

Early life is an important period for brain development and behavioral programming. Both reduced maternal care and stress in early life are risk factors for various psychiatric disorders.Here, we hypothesized that females' stressful experience in their early life can lead to a disruption of mother-offspring interactions toward their own progeny. The objective of this study is to assess the effects of mothers' past stressful experience, early-life stress alone or both on behavior in adult male mice. In this study, female mice were allowed to raise their pups either without exposure to stress (normal rearing condition, NC) or with exposure to maternal separation (3h/day, maternal separation, MS) on postnatal days 2-14. Adult F1 female mice who had experienced MS (stressed mothers, SM) or had been reared normally (undisturbed mothers, UM) were used for generating F2 offspring to be or not to be further exposed to early-life stress.We assessed anxiety-like behavior, exploratory activity, locomotor activity, aggression and cognition in four groups of adult F2 males (UM+NC, UM+MS, SM+NC, SM+MS). We found that SM+MS males become more aggressive if agonistic contact is long enough, suggesting a change in their social coping strategy. Moreover, these aggressive males tended to improve longterm spatial memory. Aggressive SM+NC males, in contrast, showed learning impairments. We did not find any significant differences in anxiety-like behavior or exploratory and locomotor activity. Overall, our findings suggest that mothers' early-life experience may have important implications for the adult behavior of their offspring.

Maternal Separation Early in Life Alters the Expression of Genes Npas4 and Nr1d1 in Adult Female Mice: Correlation with Social Behavior

“…Early-life experience can shape the developing brain and encode subsequent behavior of the individuals. Our previous studies have revealed that early-life experience leads to enhanced social behavior of females with a history of brief or prolonged maternal separation [14], and these alterations may affect the next generation too: the level of social behavior was also high (at least among males), and the social coping strategy was different in the descendants that were brought up by the mothers with a history of prolonged maternal separation [15,71]. We can theorize that the upregulation of Npas4 and Nr1d1 in females with a history of early-life stress and the corresponding enhancement of social behavior may be considered an adaptation mechanism reversing the possible aberrations caused by early-life stress.…”

Neonatal procedural pain affects state, but not trait anxiety behavior in adult rats

“…Daily postnatal handling during the first two postnatal weeks also reduced anxiety behavior in adulthood as compared with the UC (Li et al., 2018 ). In addition, differences in rearing conditions between UC and NP animals may also play a role (Reshetnikov et al., 2020 ). In preclinical studies, a second “hit” is often necessary for the long‐term effects of neonatal pain to emerge (Williams & Lascelles, 2020 ).…”

High-resolution MRI data of the brain of C57BL/6J and BTBR mice in three anatomical views

“…Each litter consisted of 5 to 8 animals. Pups in the stress group were subjected to prolonged separation from their mothers (3 h once a day) from PND2 to PND15 as described elsewhere [1 , 2] . Briefly, each pup was placed in an individual plastic box (11 × 7 cm) filled with bedding, whereas the dam stayed in the home cage during the separation procedure.…”