When mothers do not have the necessary resources to raise their children, this adversity causes a great amount of stress that can hinder caregiving towards offspring and lead to postpartum depression. New in JNeurosci, Millie Rincón-Cortés and colleagues, from the University of Texas at Dallas, used rats to explore how a lack of resources while raising pups alters neural activity. The researchers focused on a neuron population that is triggered by pup interactions and is linked to motivated behavior as well as maternal acts.
The researchers discovered that when mothers had less bedding to create nests for their pups, this led to increased neuron activity before and during harmful behavior towards the pups. When these moms were separated from their pups, they had less activity in this neuron population compared to mother rats with sufficient nesting resources. Says Rincón-Cortés, "We predicted these neurons would be changed when mothers were expressing adequate maternal care towards their pups, but that didn't happen. Opposite to our prediction, there was only increased activity right before and during insensitive behavior—it seems to be a maladaptive brain signature."
Because this neuron population is involved in general motivation, the researchers also explored whether mothers with less nesting resources had altered activity when receiving a food reward. There were no differences in activity compared to mothers with adequate nesting resources, suggesting that changes in activity are specific to the maternal caregiving context. Elaborates Rincón-Cortés, "Stress and adversity are thought to turn down activity in these cells, but this finding suggests it's not that simple. Context matters, how these neurons respond depends on what the mom is doing."
According to the authors, this work reveals how a lack of resources shapes the activity of a neuron population in mother rats to hinder caregiving. The research team has a few planned projects stemming from this work, including using a machine learning approach to identify behaviors that can predict abuse towards pups. They also are interested in exploring whether government-approved treatments can either prevent this maladaptive brain change from occurring in the rats or reverse altered brain activity following resource scarcity.
