Stressful events are inherently emotional. As a result, the ability to regulate emotions is critical in responding effectively to stressors. Differential abilities in the management of stress appear very early in life, compelling a need to better understand factors that may shape the capacity for emotion regulation (ER). Variations in both biologic and behavioural characteristics are thought to influence individual differences in ER development. We sought to determine the differential contributions of temperament and heart rate variability (HRV; an indicator of autonomic nervous system function) to infant resting state emotionality and emotional reactivity in response to a stressor at 6 months of age. Participants included 108 mother-infant dyads. Mothers completed a measure of infant temperament at 6 months postnatal. Mother and infant also participated in a standardized stressor (the Repeated Still Face Paradigm) at that time. Electrocardiographic data were acquired from the infant during a baseline resting state and throughout the stressor. Fast Fourier Transformation was used to analyse the high frequency (HF) domain of HRV, a measure of parasympathetic nervous system activity. Infant ER was measured via standardized coding of emotional distress behaviours from video-records at baseline and throughout the stressor. Severity of mothers' depressive symptoms was included as a covariate in analyses. Results of linear regression indicate that neither temperament nor HRV were associated significantly with an infant's emotional resting state, although a small effect size was found for the relationship between infant negative affectivity and greater emotional distress (β = 0.23, p = 0.08) prior to the stressor. Higher HF-HRV (suggesting parasympathetic dominance) was related to greater emotional distress in response to the stressor (β = 0.34, p = 0.009). This greater emotional reactivity may reflect a more robust capacity to mount an emotional response to the stressor when infants encounter it from a bedrock of parasympathetic activation. Findings may inform eventual markers for assessment of ER in infancy and areas for intervention to enhance infant management of emotions, especially during stressful events.

中文翻译：

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压力背景下的婴儿情绪调节：心率变异性和气质的影响

压力事件本质上是情绪化的。因此，调节情绪的能力对于有效应对压力源至关重要。压力管理的差异能力在生命的早期就出现了，因此迫切需要更好地了解可能影响情绪调节（ER）能力的因素。生物学和行为特征的变化被认为会影响内质网发育的个体差异。我们试图确定气质和心率变异性（HRV；自主神经系统功能的指标）对 6 个月大的婴儿静息状态情绪和对压力源的情绪反应的不同贡献。参与者包括 108 名母婴。母亲们在产后 6 个月时完成了婴儿气质测量。当时，母亲和婴儿还参与了标准化压力源（重复静止面孔范式）。心电图数据是从婴儿在基线静息状态和整个应激源期间获取的。快速傅立叶变换用于分析 HRV 的高频 (HF) 域，HRV 是副交感神经系统活动的量度。婴儿 ER 是通过基线和整个压力源视频记录中情绪困扰行为的标准化编码来测量的。母亲抑郁症状的严重程度被作为协变量纳入分析。线性回归的结果表明，气质和 HRV 都与婴儿的情绪静息状态没有显着相关，尽管在婴儿消极情绪和更大的情绪困扰之间的关系中发现了较小的影响（β  = 0.23，p  = 0.08）。压力源。较高的 HF-HRV（表明副交感神经占主导地位）与对压力源的反应较大的情绪困扰相关（β  = 0.34，p  = 0.009）。这种更大的情绪反应可能反映了当婴儿从副交感神经激活的基础上遇到压力源时，对压力源产生情绪反应的能力更强。研究结果可能会为婴儿期 ER 评估的最终标记以及加强婴儿情绪管理的干预领域提供信息，尤其是在应激事件期间。