Facing infant cuteness: How nurturing care motivation and oxytocin system gene methylation are associated with responses to baby schema features.

Baby schema features are a specific set of physical features-including chubby cheeks, large, low-set eyes, and a large, round head-that have evolutionary adaptive value in their ability to trigger nurturant care. In this study among nulliparous women (N = 81; M age = 23.60, SD = 0.44), we examined how sensitivity to these baby schema features differs based on individual variations in nurturant care motivation and oxytocin system gene methylation. We integrated subjective ratings with measures of facial expressions and electroencephalography (EEG) in response to infant faces that were manipulated to contain more or less pronounced baby schema features. Linear mixed effects analyses demonstrated that infants with more pronounced baby schema features were rated as cuter and participants indicated greater motivation to take care of them. Furthermore, infants with more pronounced baby schema features elicited stronger smiling responses and enhanced P2 and LPP amplitudes compared to infants with less pronounced baby schema features. Importantly, individual differences significantly predicted baby schema effects. Specifically, women with low OXTR methylation and high nurturance motivation showed enhanced differentiation in automatic neurophysiological responses to infants with high and low levels of baby schema features. These findings highlight the importance of considering individual differences in continued research to further understand the complexities of sensitivity to child cues, including facial features, which will improve our understanding of the intricate neurobiological system that forms the basis of caregiving behavior.

The Long-Term Impact of Early Life Stress on Orbitofrontal Cortical Thickness.

Early adversity has been related to brain structure alterations and to an increased risk of psychiatric disorders. The orbitofrontal cortex (OFC) is a key region for emotional processing, with structural alterations being described in several mental disorders. However, little is known about how its cortical thickness (CT) is affected by the long-term impact of life stress (LS) at different developmental stages. The present study aimed to investigate the effect of LS during infancy, childhood, and adolescence on CT alterations in the OFC and on psychopathology in 190 adults of an ongoing prospective cohort study. Chronic stressful life events were assessed in regular intervals. Participants rated depressive symptoms at the ages of 22 and 23 years. Morphometric data were collected at the participants' age of 25 years. Chronic LS during infancy was associated with reduced CT in the right OFC and increased depressive symptoms. Moreover, the impact of chronic LS during infancy on OFC thickness was partially mediated by depressive symptoms in adulthood, suggesting an interplay of early LS, psychopathology, and CT alterations. Our findings highlight the long-term impact of early LS on an affective core brain structure and psychopathology later in life.

A coordinate-based meta-analysis of human amygdala connectivity alterations related to early life adversities.

By affecting core neurobiological systems early in development, early life adversities (ELAs) might confer latent vulnerability to future psychopathologies. This coordinate-based meta-analysis aims to identify significant convergent alterations in functional connectivity of the amygdala related to ELAs across resting-state and task-based fMRI-studies. Five electronic databases were systematically searched until 22 October 2020, retrieving 49 eligible studies (n = 3162 participants). Convergent alterations in functional connectivity related to ELAs between the amygdala and the anterior cingulate cortex (ACC) and left hippocampus were found. Sub-analyses based on hemisphere and direction showed that connectivity seeded in the right amygdala was affected and, moreover, revealed that connectivity with ACC was decreased. Analyses based on paradigm and age showed that amygdala-ACC coupling was altered during resting state and that amygdala-left hippocampus connectivity was mostly affected during task-based paradigms and in adult participants. While both regions showed altered connectivity during emotion processing and following adverse social postnatal experiences such as maltreatment, amygdala-ACC coupling was mainly affected when ELAs were retrospectively assessed through self-report. We show that ELAs are associated with altered functional connectivity of the amygdala with the ACC and hippocampus. As such, ELAs may embed latent vulnerability to future psychopathologies by systematically affecting important neurocognitive systems.

Candidate diagnostic biomarkers for neurodevelopmental disorders in children and adolescents: a systematic review.

Neurodevelopmental disorders - including attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, communication disorders, intellectual disability, motor disorders, specific learning disorders, and tic disorders - manifest themselves early in development. Valid, reliable and broadly usable biomarkers supporting a timely diagnosis of these disorders would be highly relevant from a clinical and public health standpoint. We conducted the first systematic review of studies on candidate diagnostic biomarkers for these disorders in children and adolescents. We searched Medline and Embase + Embase Classic with terms relating to biomarkers until April 6, 2022, and conducted additional targeted searches for genome-wide association studies (GWAS) and neuroimaging or neurophysiological studies carried out by international consortia. We considered a candidate biomarker as promising if it was reported in at least two independent studies providing evidence of sensitivity and specificity of at least 80%. After screening 10,625 references, we retained 780 studies (374 biochemical, 203 neuroimaging, 133 neurophysiological and 65 neuropsychological studies, and five GWAS), including a total of approximately 120,000 cases and 176,000 controls. While the majority of the studies focused simply on associations, we could not find any biomarker for which there was evidence - from two or more studies from independent research groups, with results going into the same direction - of specificity and sensitivity of at least 80%. Other important metrics to assess the validity of a candidate biomarker, such as positive predictive value and negative predictive value, were infrequently reported. Limitations of the currently available studies include mostly small sample size, heterogeneous approaches and candidate biomarker targets, undue focus on single instead of joint biomarker signatures, and incomplete accounting for potential confounding factors. Future multivariable and multi-level approaches may be best suited to find valid candidate biomarkers, which will then need to be validated in external, independent samples and then, importantly, tested in terms of feasibility and cost-effectiveness, before they can be implemented in daily clinical practice.

Oxytocin system gene methylation is associated with empathic responses towards children.

Empathy is an essential component of sensitive caregiving behavior, which in turn is an important predictor of children's healthy social-emotional development. The oxytocin (OXT) system plays a key role in promoting sensitive parenting and empathy. In this study, we investigated how OXT system gene methylation was associated with empathic processes in nulliparous women (M age = 23.60, SD =0.44)-measuring both physiological facial muscle responses and ratings of compassion and positive affect to affective images depicting children. Linear mixed effects analyses demonstrated that lower methylation levels in the OXT and OXTR genes were related to enhanced empathic responses. The effect of OXT system gene methylation on empathic processes was partly qualified by an interaction with individual variations in women's care motivation. Our findings provide experimental evidence for an association between the methylation of OXT system genes and empathy.

Neurostructural traces of early life adversities: A meta-analysis exploring age- and adversity-specific effects.

Early life adversities (ELAs) are associated with an increased risk of psychopathology, with studies suggesting a relation to structural brain alterations. Given the recently growing evidence of ELA effects on brain structure, an updated summary is highly warranted. Therefore, anatomical likelihood estimation was used to conduct a coordinate-based meta-analysis of gray matter volume (GMV) alterations associated with ELAs, including sub-analyses for different age groups and maltreatment as specific ELA-type. The analyses uncovered a convergence of pooled ELA-effects on GMV in the right hippocampus and amygdala and the left inferior frontal gyrus, age-specific effects for the right amygdala and hippocampus in children and adolescents, and maltreatment-specific effects for the right perigenual anterior cingulate cortex in adults. These results reveal a possible underlying commonality in the impact of adversity and also point to specific age and maltreatment effects. They suggest neural markers of ELAs in regions involved in socio-emotional functioning and stress regulation, with the potential to be used as targets for interventions designed to buffer or reverse harmful ELA-effects.

Methylation of oxytocin related genes and early life trauma together shape the N170 response to human faces.

Childhood trauma fundamentally shapes social cognition and basic processing of social cues, which frequently cascade into adverse behavioral outcomes. Recent studies indicate that epigenetic changes in oxytocin functioning might contribute to these long-term effects, although a deeper understanding of the underlying mechanisms is still lacking. The electroencephalographic N170 response to faces might capture a neural response at the core of these interactive effects of oxytocin gene methylation and childhood adversity, given that this response is considered to reflect fundamental face processing, to be susceptible to oxytocin administration and also to be a biomarker of various psychiatric disorders. We assessed the N170 response to neutral faces in relation to participant's (81, women) recalled childhood trauma, methylation of their oxytocin structural (OXTg) and oxytocin receptor (OXTRg) genes, and endogenous levels of cortisol and testosterone. Additionally, we investigated the interactive effect of OXTg methylation and CTQ across three face sets of varying maturity. Methylation of OXTg relates to a weakened N170 response towards adults, children and infants. Moreover, methylation of both OXTRg and OXTg shaped the directionality of adversity effects, predicting a weakened N170 response in those with high methylation and hyper-vigilance with participants with low methylation. Our results are the first to relate OXT(R)g methylation to the N170 response. They shed light on biological processes linking childhood adversity and epigenetic marks to altered behavior and potentially psychopathologies.

Epigenetic variability in the human oxytocin receptor (OXTR) gene: A possible pathway from early life experiences to psychopathologies.

The human oxytocin (OXT) system is implicated in the regulation of complex social behaviors, as well as in psychopathologies characterized by social deficits. Emerging evidence suggests that variation in epigenetic regulation of the oxytocin receptor gene (OXTR) provides the oxytocin system with flexibility in response to environmental events, especially those occurring during early childhood. Changes in DNA methylation patterns of OXTR associated with these events may reflect biological alterations of social sensitivity. This is often related to an increased risk of developing mental disorders later in life. Here, we systematically reviewed all human studies (n = 30) discussing OXTR methylation in relation to socio-behavioral phenotypes. As such, we provide a complete and up-to-date overview of the literature that will aid future research in the interdisciplinary field of epigenetics and socio-behavioral sciences.

A neuroendocrine account of facial mimicry and its dynamic modulation.

Facial expressions are considered central in conveying information about one's emotional state. During social encounters, facial expressions of another individual are often automatically imitated by the observer, a process referred to as 'facial mimicry'. This process is assumed to facilitate prosocial behaviour and is thought to rely on the mirror neuron system, known for its involvement in both observation and execution of motor actions. However, recent studies have revealed mimicry to be a more dynamic process than previously conceptualized, leaving mere perception-action coupling insufficient to explain its behavioural flexibility. In the current review, we describe the consequences of these findings for the theoretical conceptualization of facial mimicry, and present a novel neuroendocrine model for the dynamic modulation of facial mimicry. Our model can guide research on the communicative function of facial expressions and can provide insight into the position of facial mimicry in theoretical models of empathy and social interaction.