A recent study conducted on mice suggests that a middle-brain region associated with emotion control could be responsible for prompting females to kill their young. The findings, led by researchers at NYU Grossman School of Medicine, shed light on the brain mechanisms underlying infanticide in female mice and may contribute to a better understanding of similar behaviors in humans.
While infanticide by adult males has been extensively studied, little was known about the brain mechanisms behind this behavior in females. Female mice, prior to giving birth for the first time, have been observed to kill the pups of others, potentially to secure limited food resources for their own offspring.
The research team focused on a region called the principal nucleus of the bed nucleus of stria terminalis (BNSTpr) and discovered that blocking its activity prevented infanticide in almost all cases. Conversely, when the region was artificially stimulated, both mothers and non-mothers exhibited high aggression towards pups. This aggressive behavior was specific to young animals, as adult mice were rarely targeted.
The study also revealed an antagonistic relationship between the BNSTpr and another brain region called the medial preoptic area (MPOA), known for promoting maternal behaviors. Prior to motherhood, mice displayed high BNSTpr activity, which suppressed the MPOA. After giving birth, the MPOA became more active, inhibiting the infanticidal system. Interestingly, new mothers showed a tendency to avoid infanticide, irrespective of whether the pup was their own.
According to Dr. Long Mei, the lead author of the study, this research provides valuable insights into the brain mechanisms underlying infanticide in females. The findings have implications for understanding and potentially addressing child abuse, which is a significant cause of death among preschool children in the United States.
The study, published in the journal Nature, also suggests that the transition to maternal behaviors can be reversed by applying additional pressure to the BNSTpr. However, it is important to note that the extent to which these brain regions perform similar roles in humans remains uncertain.
Moving forward, the research team plans to investigate the BNSTpr and MPOA in male mice and explore non-invasive methods of inhibiting BNSTpr activity. The study was supported by grants from the National Institutes of Health and the Leon Levy Foundation.
In addition to Dr. Mei and Dr. Lin, other investigators from NYU Langone involved in the study were Dr. Rongzhen Yan, Dr. Luping Yin, and Dr. Regina M. Sullivan.