Infant-caregiver interactions shape brain development and have lifelong consequences for mental health

María Eugenia Pallarés

Laboratorio de Programación Perinatal del Neurodesarrollo, IBCN- Facultad de Medicina, UBA

In mammals, caregivers-offspring interactions are an important developmental cue for the environmental quality that prepares offspring for the conditions of life. Also, these interactions can impact on the individual’s growth and behavior. In humans, adverse caregivers-offspring bond includes neglect, maltreatment, and exposure to toxic stress by at least one of the caregivers. Those adverse early bonds raise the risk for psychiatric disorders throughout the lifespan of the individual. In animals, biparental care is relatively rare and these interactions are primarily through the mother. Several rodent models have been established to manipulate the quality of mother-infant interactions during early postnatal life. Evidence from these studies helped to gain a better understanding of the mechanisms by which these interactions impact neurobehavioral development in the offspring and induce later-life behavioral consequences. In this Symposium we present novel knowledge driven by four renown leaders in the field that have used different research approaches to study the impact of maternal care on brain and behavior development in rodent offspring. Although the approach of each speaker is interestingly different, al succeed in delineating a specific aspect of how early-life experiences driven by caregivers influences the offspring outcome. Taken together, their studies strengthen the idea that the trajectory of the developing brain is influenced by early-life experiences.

Mothers neglect their young when peripartum adaptations of the CRF system fail

Oliver Bosch

University of Regensburg

The peripartum brain undergoes dramatic changes in order for the mother to become fully maternal. This is the result of a concerted balance of “pro-maternal” versus “anti-maternal” neuromodulators, such as the oxytocin and vasopressin systems on one hand versus the corticotropin-releasing factor (CRF) system on the other hand. When these adaptations fail, the outcome can be dramatic, e.g. leading to postpartum mood disorders with all its consequences for mother and offspring. For example, in the biparental prairie voles, a lactating mother that has lost its male partner experiences increased emotionality but shows normal maternal care. However, the offspring miss the paternal investment. Furthermore, in uniparental mouse and rat mothers, increased activity of the CRF system in maternal brain regions like the lateral septum, the bed nucleus of the stria terminalis or the medial preoptic area leads to reduced maternal investment in the young. This might be partly due to the CRF system directly affecting local oxytocin release. In summary, the behavioral effects of increased CRF signaling on the maternal brain are not only brain region- but also receptor subtype-specific. Such findings might help us to advance our understanding of the complex basis of postpartum mood disorders and the implications of the CRF system therein.

Early life stress and the programming of motivated behaviors and cognition

Carla Dalmaz

Universidade Federal do Rio Grande do Sul

Early life experiences program lifelong responses to stress, as well as behavior in adulthood, including those related to motivation and cognition. In this sense, resilience and vulnerability to psychopathologies have been suggested to be affected by early adversities. Here we discuss some of the effects of early life experiences on eating behavior and on some aspects of cognition using animal models. Furthermore, we consider some neurochemical alterations possibly underlying these observations.

A translational approach to investigate mechanisms underlying intergenerational inheritance of depression

Chris Murgatroyd

Manchester Metropolitan University


Stress during early life such as exposure to prenatal and postnatal depression or receiving reduced levels of parental care can produce long-lasting behavioral effects. Such long-term disruptions in stress-related behaviors have been seen in both human and rodent studies in offspring exposed to a variety early-life stressors such as maternal depression. Importantly, offspring exposed to early life stress have increased susceptibility to maternal depression themselves suggesting a mechanism by which stress could be intergenerationally inherited through maternal stress. We have been exploring the possible mechanisms underlying how maternal stress and reduced care is able to increase the risk of developing stress-related behavioral disorders in the offspring. We found a number of generational changes in neuroendocrine and immune factors together with epigenetic and transcriptome changes supporting these as mechanisms in the transmission of maternal stress. We are now using this work to develop targets that are currently being investigating in relevant human studies.

Developmental transitions in brain networks of attachment and fear: Rodent model of human development

Regina Sullivan

Nathan Kline Institute, New York University Langone Medical Center


We have known since the 1950s that the quality of care infants receive from parents has enduring effects on brain circuits controlling emotion and cognition, as well as ubiquitous changes in gene regulation, epigenetics, myriad neurotransmitters/hormone, and brain anatomy throughout the brain. However, mechanisms by which experiences initiate different developmental pathways remain incompletely understood. Here we focus on one variable during mother-infant interactions: how well the mother buffers (attenuates) the offspring’s stress response and aberrant infant behavior. Using a rodent animal model, we have begun to question the neurobiology of social buffering within attachment during typical rearing, as well as within trauma associated interactions with the parent (maltreatment). First, within typical attachment, we present data illustrating how mothers’ social buffering of pups’ stress response can alter the offspring’s amygdala and its network to alter learning about trauma. Next, we present data showing how maltreatment by the mother blunts this neural network processing. Finally, we present within nest neurobehavioral data for ecological significance suggesting the mother is engaged in moment-to-moment regulation of pups’ cortical and amygdala oscillations, which is also disrupted in pups maltreated by the mother. For all examples, maternal regulation of the offspring’s brain decreases as pup approaches independence and is disrupted by adversity (maltreatment).