Prospective associations between maternal mind-mindedness, child theory of mind, and brain morphology in school-aged children.

Mentalizing is defined as the ability to attribute mental states to oneself and others. In the context of parental behavior, parents' tendency to comment on their child's mental activities refers to the concept of mind-mindedness (MM). MM has been positively associated with various developmental outcomes in children, notably their own ability to mentalize, known as theory of mind (ToM). Although parental (MM) and child (ToM) mentalizing have important implications during childhood, their associations with children's neural structures are largely unknown. Among 62 mother-child dyads, maternal MM was rated from free-play sequences when children were aged 1 year, child ToM was assessed using a first-order false-belief task at 4 years of age, and structural MRI images were acquired at 10 years of age. Maternal MM was positively associated with gray matter volumes (GMV) in the dorsal prefrontal cortex and the superior temporal pole. Child ToM abilities were positively associated with GMV in the ventromedial prefrontal cortex. Though cortical regions associated with MM and ToM showed no anatomical overlap, many are functionally connected through a neural network highly involved in self-referential strategies for mentalizing. These findings suggest that MM and ToM may contribute to distinct sub-processes that collectively support social cognition development.

Longitudinal associations between mother-child attachment security in toddlerhood and white matter microstructure in late childhood: a preliminary investigation.

Early childhood experiences are considered to influence the strength and effectiveness of neural connections and thus the development of brain connectivity. As one of the most pervasive and potent early relational experiences, parent-child attachment is a prime candidate to account for experience-driven differences in brain development. Yet, knowledge of the effects of parent-child attachment on brain structure in typically developing children is scarce and largely limited to grey matter, whereas caregiving influences on white matter (i.e. neural connections) have seldom been explored. This study examined whether normative variation in mother-child attachment security predicts white matter microstructure in late childhood and explored associations with cognitive-inhibition. Mother-child attachment security was assessed using home observations when children (N = 32, 20 girls) were 15 and 26 months old. White matter microstructure was assessed using diffusion magnetic resonance imaging when children were 10 years old. Child cognitive-inhibition was tested when children were 11 years old. Results revealed a negative association between mother-toddler attachment security and child white matter microstructure organization, which in turn related to better child cognitive-inhibition. While preliminary given the sample size, these findings add to the growing literature that suggests that rich and positive experiences are likely to decelerate brain development.

Disorganized attachment behaviors in infancy as predictors of brain morphology and peer rejection in late childhood.

Studies show robust links between disorganized attachment in infancy and socioemotional maladjustment in childhood. Little is known, however, about the links between disorganized attachment and brain development, and whether attachment-related differences in brain morphology translate into meaningful variations in child socioemotional functioning. This study examined the links between infants' disorganized attachment behaviors toward their mothers, whole-brain regional grey matter volume and thickness, and peer rejection in late childhood. Thirty-three children and their mothers took part in this study. The Strange Situation Procedure was used to assess mother-infant attachment when infants were 18 months old. Magnetic resonance imaging was performed when they were 10 years old to assess cortical thickness and grey matter volumes. Children and teachers reported on peer rejection 1 year later, as an indicator of socioemotional maladjustment. Results indicated that disorganized attachment was not associated with grey matter volumes. However, children who exhibited more disorganized attachment behaviors in infancy had significantly thicker cortices in bilateral middle and superior frontal gyri, and extending to the inferior frontal gyrus, as well as the orbitofrontal and insular cortices in the right hemisphere in late childhood. Moreover, children with thicker cortices in these regions experienced greater peer rejection, as rated by themselves and their teachers. Although preliminary, these results are the first to indicate that disorganized attachment may play a role in cortical thickness development and that changes in cortical thickness are associated with differences in child socioemotional functioning.

Socioeconomic Status in Infancy and the Developing Brain: Functional Connectivity of the Hippocampus and Amygdala.

The development of the hippocampus and amygdala is particularly sensitive to environmental factors, including socioeconomic status (SES). Studies that have investigated associations between SES and brain development markers have rarely focused on connectivity. Accordingly, this longitudinal study examined whether SES in infancy (parental education and income-to-needs ratio) predicts the functional connectivity of the hippocampus and amygdala in late childhood, and in turn whether functional connectivity is associated with child socioemotional adjustment in a middle-class sample. SES indices were measured when children (n = 28) were 7 months old. When children were 10 years of age, they underwent a resting-state functional magnetic resonance imaging exam, and their school teachers completed a questionnaire assessing child socioemotional adjustment. Whole-brain regression analyses, including left and right hippocampi and amygdalae as seeds and SES indices as predictors, revealed that higher parental education predicted stronger functional connectivity between the left and right hippocampi and the right amygdala with the dorsal anterior cingulate cortex, and between the left amygdala and bilateral angular gyrus, after accounting for child age and sex. In turn, the connectivity of these regions was associated with higher child prosocial behavior. These findings contribute to the emerging literature suggesting that SES is associated with variability in the neural substrates of social abilities in children.

Mother-Infant Interaction and Child Brain Morphology: A Multidimensional Approach to Maternal Sensitivity.

Emerging research suggests that normative variation in parenting quality relates to children's brain development. However, although the young brain is presumed to be especially sensitive to environmental influence, to our knowledge only two studies have examined parenting quality with infants as it relates to indicators of brain development, and both were cross-sectional. This longitudinal study investigated whether different components of maternal sensitivity in infancy predicted the volume of two brain structures presumed to be particularly sensitive to early experience, namely the amygdala and the hippocampus. Three dimensions of sensitivity (Cooperation/Attunement, Positivity, Accessibility/Availability) were observed in 33 mother-infant dyads at 1 year of age and children underwent structural magnetic resonance imaging at age 10. Higher maternal Accessibility/Availability during mother-infant interactions was found to be predictive of smaller right amygdala volume, while greater maternal positivity was predictive of smaller bilateral hippocampal volumes. These longitudinal findings extend those of previous cross-sectional studies and suggest that a multidimensional approach to maternal behavior could be a fruitful way to further advance research in this area, given that different facets of parenting might be differentially predictive of distinct aspects of neurodevelopment.

Systematic Review and Inventory of Theory of Mind Measures for Young Children.

Theory of mind (TOM), the ability to infer mental states to self and others, has been a pervasive research theme across many disciplines including developmental, educational, neuro-, and social psychology, social neuroscience and speech therapy. TOM abilities have been consistently linked to markers of social adaptation and have been shown to be affected in a broad range of clinical conditions. Despite the wealth and breadth of research dedicated to TOM, identifying appropriate assessment tools for young children remains challenging. This systematic review presents an inventory of TOM measures for children aged 0-5 years and provides details on their content and characteristics. Electronic databases (1983-2019) and 9 test publisher catalogs were systematically reviewed. In total, 220 measures, identified within 830 studies, were found to assess the understanding of seven categories of mental states and social situations: emotions, desires, intentions, percepts, knowledge, beliefs and mentalistic understanding of non-literal communication, and pertained to 39 types of TOM sub-abilities. Information on the measures' mode of presentation, number of items, scoring options, and target populations were extracted, and psychometric details are listed in summary tables. The results of the systematic review are summarized in a visual framework "Abilities in Theory of Mind Space" (ATOMS) which provides a new taxonomy of TOM sub-domains. This review highlights the remarkable variety of measures that have been created to assess TOM, but also the numerous methodological and psychometric challenges associated with developing and choosing appropriate measures, including issues related to the limited range of sub-abilities targeted, lack of standardization across studies and paucity of psychometric information provided.

Quality of maternal behaviour during infancy predicts functional connectivity between default mode network and salience network 9 years later.

Infants' experiences are considered to determine to a large degree the strength and effectiveness of neural connections and fine tune the development of brain networks. As one of the most pervasive and potent relational experiences of infancy, parent-child relationships appear to be prime candidates to account for experience-driven differences in children's brain development. Yet, studies linking parenting and functional connectivity are surprisingly scarce, and restricted to the connectivity of limbic structures. Accordingly, this longitudinal study explored whether normative variation in the quality of early maternal behaviour predicts the functional connectivity of large-scale brain networks in late childhood. Maternal mind-mindedness and autonomy support were assessed with 28 children when they were 13 and 15 months old respectively. When children were 10 years of age, children underwent a resting-state functional MRI exam. Functional connectivity was assessed between key regions of the default mode network (DMN), salience network (SN), and frontal-parietal central executive network (CEN). Results revealed that higher mind-mindedness and autonomy support predicted stronger negative connectivity between DMN and SN regions. These findings are the first to provide preliminary evidence suggestive of a long-lasting impact of variation within the normative range of early maternal behaviour on functional connectivity between large-scale brain networks.

Attachment Security in Infancy: A Preliminary Study of Prospective Links to Brain Morphometry in Late Childhood.

A large body of longitudinal research provides compelling evidence for the critical role of early attachment relationships in children's social, emotional, and cognitive development. It is expected that parent-child attachment relationships may also impact children's brain development, however, studies linking normative caregiving experiences and brain structure are scarce. To our knowledge, no study has yet examined the associations between the quality of parent-infant attachment relationships and brain morphology during childhood. The aim of this preliminary study was to investigate the prospective links between mother-infant attachment security and whole-brain gray matter (GM) volume and thickness in late childhood. Attachment security toward the mother was assessed in 33 children when they were 15 months old. These children were then invited to undergo structural magnetic resonance imaging at 10-11 years of age. Results indicated that children more securely attached to their mother in infancy had larger GM volumes in the superior temporal sulcus and gyrus, temporo-parietal junction, and precentral gyrus in late childhood. No associations between attachment security and cortical thickness were found. If replicated, these results would suggest that a secure attachment relationship and its main features (e.g., adequate dyadic emotion regulation, competent exploration) may influence GM volume in brain regions involved in social, cognitive, and emotional functioning through experience-dependent processes.

Maternal Psychosocial Maladjustment and Child Internalizing Symptoms: Investigating the Modulating Role of Maternal Sensitivity.

In light of evidence suggesting that maternal adaptation may impact early child emotional development, this study investigated the interactive effects of maternal psychosocial maladjustment and maternal sensitivity on child internalizing symptoms, with the aim of investigating the potentially protective function of maternal sensitivity. Families (N = 71 to 106 across measures, with gender spread almost evenly: number of boys = 31 to 51 across measures) took part in four assessments between child ages 1 and 3 years. Mothers completed measures of parental stress, psychological distress, and marital satisfaction when their children were between 12 and 15 months. A composite score of maternal psychosocial maladjustment was derived from these measures. Maternal sensitivity was rated by trained observers at 12 months following a home visit. Child internalizing symptoms were assessed by both parents when the child was 2 and 3 years old. Hierarchical regressions revealed that increased maternal psychosocial maladjustment was related to more internalizing symptoms in children, however only among children of less sensitive mothers. In contrast, children of more sensitive mothers appeared to be protected. This was observed with maternal reports at 2 years, and both maternal and paternal reports at 3 years. These results suggest that young children may be differentially affected by their parents' emotional adjustment, while highlighting the pivotal protective role of maternal sensitivity in this process.