Andrea Gonzalez

Mothering begets mothering: The transmission of behavior and its neurobiology across generations

Early experiences exert their effects on adult parental behavior in part by altering the development of neurobiological mechanisms that initiate or support the initiation and sustenance of adult parental behavior. The effects of parental behavior on sensory, perceptual and emotional mechanisms in offspring constitute an experientially based mechanism by which neurobiological factors regulating behavior can be transferred from generation to generation somewhat independently of genetic endowment.

The relation between early life adversity, cortisol awakening response and diurnal salivary cortisol levels in postpartum women

Early life adversity has been associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction in both children and adults. However, in adulthood, most studies have focused on the effects of early adversity on HPA axis stress reactivity rather than the cortisol awakening response or diurnal cortisol profiles. The goal of this study was to examine the cumulative effects of early life adversity on the cortisol awakening response (CAR) and diurnal cortisol profiles in a sample of postpartum women. Ninety women between 2 and 6 months postpartum completed two retrospective reports assessing adverse early life experiences (maltreatment and consistency of care). Eighteen women reported having experienced both parental loss and some form of childhood maltreatment and 36 women reported having experienced one type of early life adversity, either parental loss or maltreatment. HPA axis function was assessed through salivary cortisol collections over two consecutive days for measurement of the cortisol awakening response (n=61) and diurnal cortisol rhythm (n=90). Women who reported experiencing adverse early life experiences exhibited a tendency towards higher levels of awakening cortisol compared to women who reported no adverse early life experiences (p=.07). These higher awakening cortisol levels were sustained throughout the morning in the groups who experienced early adversity, with all groups exhibiting the typical diurnal decline in the afternoon and evening (p<.05). Women reporting early adversity exhibited more heterogeneity in their diurnal cortisol levels across the two collection days (p<.01). Our findings suggest that in a community sample of postpartum women, early adversity is associated with current HPA axis function. These findings may have implications for the nature of mother-infant interactions.

Maternal affect and quality of parenting experiences are related to amygdala response to infant faces

We examined how individual differences in mood and anxiety in the early postpartum period are related to brain response to infant stimuli during fMRI, with particular focus on regions implicated in both maternal behavior and mood/anxiety, that is, the subgenual anterior cingulate cortex (sgACC) and the amygdala. At approximately 3 months postpartum, 22 mothers completed an affect-rating task (ART) during fMRI, where their affective response to infant stimuli was explicitly probed. Mothers viewed/rated four infant face conditions: own positive (OP), own negative (ON), unfamiliar positive (UP), and unfamiliar negative (UN). Mood and anxiety were measured by the Edinburgh Postnatal Depression Scale (EDPS) and the State-Trait Anxiety Inventory-Trait Version (STAI-T); maternal factors related to parental stress and attachment were also assessed. Brain-imaging data underwent a random-effects analysis, and cluster-based statistical thresholding was applied to the following contrasts: OP–UP, ON–UN, OP–ON, and UP–UN. Our main finding was that poorer quality of maternal experience was significantly related to reduced amygdala response to OP compared to UP infant faces. Our results suggest that, in human mothers, infant-related amygdala function may be an important factor in maternal anxiety/mood, in quality of mothering, and in individual differences in the motivation to mother. We are very grateful to the staff at the Imaging Research Center of the Brain-Body Institute for their contributions to this project. This work was supported by an Ontario Mental Health Foundation operating grant awarded to Alison Fleming and a postdoctoral fellowship awarded to Jennifer Barrett.

Parenting stress mediates between maternal maltreatment history and maternal sensitivity in a community sample.

OBJECTIVE Maternal maltreatment history and current parenting stress are associated with parenting difficulties. However, researchers have not investigated the mechanism by which these variables are interlinked. We hypothesized that parenting stress mediates the relation between history of maltreatment and parenting behavior. METHODS We assessed a community sample of 291 mothers as they interacted with their 16-month old infants in the home. Maternal history of maltreatment and parenting stress were assessed via self-report inventory; maternal sensitivity toward the infant was assessed with 2h of direct behavioral observation. RESULTS Mothers who reported more maltreatment in childhood were less sensitive with their infants; mothers who reported more current parenting stress were also less sensitive. Parenting stress mediated between maternal maltreatment history and current parental behavior. CONCLUSIONS Findings are consistent with an interpretation of parenting stress as a pathway through which maternal history of maltreatment may be linked to decreased maternal sensitivity.

New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile

Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.

Maternal Early Life Experiences and Parenting: The Mediating Role of Cortisol and Executive Function

OBJECTIVE Research suggests that early life adversity may affect subsequent parenting. Animal studies investigating mechanisms of transmission have focused on biological factors; whereas research in humans has emphasized cognitive and psychosocial factors. We hypothesized that neuropsychological and physiological factors would act as mediators between maternal retrospective reports of early life experiences (ELE) and current parenting. METHOD We recruited a community sample of 89 mothers and their infants (2-6 months of age). Maternal ELE consisted of self-reports of consistency of care and childhood maltreatment. Diurnal salivary cortisol samples were collected as the measure of hypothalamic-pituitary-adrenal (HPA) function. Executive function measures included attentional set-shifting and spatial working memory. Maternal sensitivity was assessed through videotapes of mothers interacting with their infants. RESULTS A series of path analyses indicated that maternal ELE was indirectly related to maternal sensitivity via two pathways: one through HPA function, and the other through HPA function and spatial working memory. There was no direct path between maternal ELE and parenting. CONCLUSION These findings provide support for the notion that mediators linking early life experiences to parenting in humans may be similar to physiological mechanisms found in animal models. As maternal care is associated with numerous infant outcomes, our findings may have broad relevance to understanding the risk associated with parenting and adverse outcomes in infants. A greater understanding of mechanism is important to informing interventions targeted at disrupting maladaptive trajectories of parenting.

Artificial rearing causes changes in maternal behavior and c-fos expression in juvenile female rats.

This study investigated the effects of early-rearing experiences on responsiveness to pups and on the pattern of c-fos activation in the brain of juvenile female rats. From Days 4 to 20, littermate females were reared with their mothers (MR) or artificially (AR). AR rats received minimal licking-like tactile stimulation (AR-min) or maximal stimulation (AR-max). On Day 20, rats were exposed to pups for 4 or 8 days, exposed to a playmate for 4 or 8 days, or left in isolation for 4 or 8 days. Compared with MR rats, pup-exposed AR rats engaged in less pup licking, and all AR rats showed significant reductions in c-fos immunoreactivity in the medial preoptic area and the parietal and piriform cortices. The AR-min group showed the greatest difference in Fos-lir compared with the MR groups. Possible mechanisms that mediate the effects of rearing on the development of neural circuits underlying maternal behavior are discussed.

Maternal sensitivity and infant and mother adrenocortical function across challenges

Findings regarding associations between maternal sensitivity and infant and mother adrenocortical function have been inconsistent. Nor have studies addressed the issue of intra-individual, between-challenge cortisol variability in the context of maternal sensitivity. In this study, we combine several design features aimed at sensitizing analyses to these issues. Cortisol secretion of 297 infants and their mothers was assessed in response to different challenges at 16 and 17 months. Extensive, structured observations of maternal sensitivity were conducted at infant age 16 months. Data were analyzed with multilevel modeling using an actor-partner interdependence model. We found that maternal sensitivity was related to infant, but not maternal, cortisol levels and also to infant-mother cortisol attunement. Infants of more sensitive mothers, as compared to infants of less sensitive mothers, showed greater cortisol variability across challenges, with relatively steep cortisol decreases and increases, depending on challenge. Mother and infant cortisol levels were highly correlated and this attunement was higher among dyads with more sensitive mothers than among dyads with less sensitive mothers. The results show nuanced attunement in a low-risk sample, with the infants of higher sensitivity mothers showing greater intra-individual variability across challenges. High cortisol response variability across challenges may simultaneously permit adaptation to threat and protect the infant from overexposure to corticosteroids.

Childhood and family influences on depression, chronic physical conditions, and their comorbidity: Findings from the Ontario Child Health Study

BACKGROUND Previous research has shown that various childhood risk factors are related to depression and chronic physical conditions (CPCs) later in life. However, little is known about risk factors associated with comorbidity for these conditions. The purpose of this study was to examine the association between individual (school performance, childhood physical and sexual abuse) and family risk variables (socioeconomic status, parental mental health, medical condition, and functional limitation) with depression only, chronic pain conditions (back pain and headaches) or other CPCs (respiratory, cardiovascular and digestive disorders, and diabetes) and the comorbidity of either CPC category with depression assessed in early adulthood. METHODS We used data from the Ontario Child Health Study, a prospective, population-based study of 3294 children (ages 4-16) enrolled in 1983 and meeting inclusion criteria at follow-up in 2001 (N = 1475; ages 21-35 years). RESULTS Using multinomial logistic regression models, controlling for sex and age, childhood history of physical abuse was associated with most outcomes (OR = 1.86, 95% confidence interval [CI] 1.16-2.97 to 4.36, 95% CI, 1.74-10.97). Parental mental health, childhood functional limitation, childhood history of sexual abuse and family functioning were all related to comorbid depression and chronic pain conditions. Parental mental health was also related to increased risk of other CPCs (ORs = 1.66; 95% CI, 1.08-2.55). CONCLUSION We found that the greatest disease risk (comorbid depression and chronic pain conditions) was related to the greatest number of childhood risk factors. Although there was some evidence of specificity, there was overlap in childhood physical abuse predicting almost all outcomes. Efforts targeting the prevention and treatment of childhood maltreatment are critical in order to prevent the long lasting impact of childhood adversity on mental and physical outcomes in early adulthood.

Preventing child maltreatment: an evidence-based update.

Child maltreatment is a significant public health problem associated with a broad range of negative outcomes in children and adolescents that can extend into adulthood. This review summarizes information about programs aimed at the prevention of child maltreatment evaluated by controlled trials, with a focus on home visitation programs. It does not include programs aimed at prevention of child sexual abuse, the subject of a separate review in this series. We discuss those programs that include one or more measures of child maltreatment and related outcomes (reports of abuse and neglect, injuries, hospitalizations and emergency room visits). Most programs targeting at-risk families have not shown evidence of effectiveness in preventing abuse or neglect. An important exception is the Nurse Family Partnership (NFP), a program provided by nurses to first-time socially disadvantaged mothers beginning prenatally that has undergone rigorous evaluation in three randomized controlled trials. It has shown consistent effects in reducing reports of maltreatment and associated outcomes as well as additional benefits in maternal and child health in high-risk families. A second exception is the promising Early Start program provided by nurses and social workers to at-risk families beginning postnatally. One randomized controlled trial of the program has shown reduced rates of parental reports of severe abuse and hospital attendance for injuries and poisonings, based on records. The characteristics of the NFP and Early Start programs are discussed with special emphasis on ways in which they differ from other home visitation programs.