Behavioral Epigenetics and Socioemotional Development in Infancy Open Access

Murphy, Jordan (Spring 2020)

Permanent URL: https://etd.library.emory.edu/concern/etds/kd17ct94m?locale=en
Published

Abstract

Background:Self-regulation emerges in infancy within a co-regulatory environment and helps to manage the stress and novelty of social experiences. Infants can, for example, look toward or away from stimuli to moderate arousal and facilitate social engagement. Maternal mood is also strongly related to infant self-regulation and may influence epigenetic processes such as DNA methylation. Additional research is needed to explore these relationships more closely.

Purpose: To examine DNA methylation of the oxytocin gene (OXT) and oxytocin receptor gene (OXTR), and salivary oxytocin in infants, and maternal oxytocin and report of depression, anxiety, and perceived stress symptoms as predictors of infant gaze self-regulation.

Methods: Forty-two mother-infant dyads were recruited from an ongoing study. DNA methylation of OXT and OXTR was measured from infant buccal cells. Maternal and infant oxytocin was collected from saliva pre- and post- mother-infant interaction in a social environment. Questionnaires ascertained maternal symptoms of depression, anxiety, or perceived stress. Infant gaze was micro-coded using a 1-second time frame for three minutes. A multilevel-time series analysis first assessed group and individual trajectories in gaze, prior to creating a level-1 model of infant gaze self-regulation using a 4-second time window of prior gaze behavior predicting current gaze behavior. Demographic, oxytocinergic, and maternal mood predictors were tested at level-2 of the multilevel model. 

Results: Significant group and individual trajectories in gaze were observed. At level-1, gaze self-regulation was dynamic at 1 (OR= 16.07, CI= 12.76 -20.29), 2 (OR= 1.14, CI= 0.87-1.51), and 3 (OR= 1.33, CI= 1.03-1.71) seconds. At level-2, an interaction between OXT and OXTR predicted infant gaze self-regulation (OR= 1.16, CI= 1.02-1.32). Maternal symptoms of depression, anxiety, perceived stress, and mother and infant salivary oxytocin did not predict infant gaze self-regulation.

Conclusions: Infant prior gaze behavior and DNA methylation of the OXT and OXTR genes are potential biobehavioral markers that inform infant gaze self-regulation. Further research is needed to confirm the novel findings of this dissertation and to understand how biobehavioral markers of social engagement relate to self-regulation and socioemotional development. Translational research with pediatric clinicians will help expand knowledge within the field of behavioral epigenetics. 

Table of Contents

Chapter 1 –     Introduction and Review of the Literature                             

Synopsis of the Dissertation Approach 1

Regulation Theory 5

Behavioral Epigenetics 8

Biological Domain of Socioemotional Development 12

Behavioral Domain of Socioemotional Development 21

Emotional Homeostasis 27

Expanded Approach of the Dissertation 30

References 40

Chapter 2 – Emotional Self-regulation: Visual Attention Shifting and Methylation of OXT and OXTR in Infancy

Abstract 69

Background 71

Materials and Methods 78

Results 84

Discussion 87

Limitations 93

Conclusions 94

Figure 1: Consort Diagram of Participant Eligibility and Inclusion in Data Analysis. 96                           

Table 1: Demographic and clinical characteristics of mothers and their infants at 6-months of age 97

Table 2: The effect of time on infant current gaze behavior modeled as a fixed and random slope 98

Figure 2: Predicted Probabilities of Infant Gaze Utilizing a Fixed and Random Slope. 99

Table 3: Level-1 model of infant gaze self-regulation 100

Table 4: Descriptive characteristics of oxytocinergic predictors 101

Table 5: Level-1 model of infant gaze self-regulation with level-2 oxytocinergic predictors 102

Figure 3: Predicted Probabilities of Infant Gaze Utilizing Oxytocinergic Predictors. 102

References 103

Chapter 3 – Emotional Self-regulation: Maternal Mood and Infant Visual Attention in a Social Environment

Abstract 114

Background 116

Materials and Methods 121

Results 126

Discussion 129

Limitations 130

Conclusions 131

Figure 1: Consort Diagram of Participant Eligibility and Inclusion in Data Analysis. 132

Table 1: Demographic and clinical characteristics of mothers and their infants at 6-months of age 133

Table 2: The effect of time on infant current gaze behavior modeled as a fixed and random slope 134

Figure 2: Predicted Probabilities of Infant Gaze Utilizing a Fixed and Random Slope. 135

Table 3: Level-1 model of infant gaze self-regulation 136

Table 4: Descriptive characteristics of maternal mood and oxytocin hormone 137

Table 5: Level-1 model of infant gaze self-regulation with level-2 EDS and oxytocin predictors 137

Table 6: Level-1 model of infant gaze self-regulation with level-2 STAI and oxytocin predictors 138

Table 7: Level-1 model of infant gaze self-regulation with level-2 PSS and oxytocin predictors 138

References 139

Chapter 4 – Translational Research for Preventative Models of Healthcare: Behavioral Epigenetics and the Pediatric Well Visit

Abstract 150

Background 152

Discussion 164

Conclusions 168

References 169

Chapter 5 – Emotional Homeostasis and the Mother-Infant Relational Environment 

Emotional Homeostasis and the Mother-Infant Relational Environment 183

References 188

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