Neuroscience Graduate Program, McMaster University, Hamilton, ON, Canada.
Department of Psychology, University of Toronto at Mississauga, Mississauga, ON, Canada.
J Neuroendocrinol. 2019 Sep;31(9):e12790. doi: 10.1111/jne.12790. Epub 2019 Sep 29.
In many mammalian species, new mothers show heightened positive responsiveness to infants and their cues when they give birth. As is evident from non-human and human studies, the amygdala is a brain region implicated in both the maternal and affective neural circuitry, and is involved in processing socioemotionally salient stimuli. In humans, infants are socially salient stimuli to women, and mothers in particular. Neuroimaging studies investigating the maternal response to infant cues have identified infant-related amygdala function as an important factor in maternal anxiety/depression, in the quality of mothering and in individual differences in the motivation to mother. The present study investigated the effects of maternal status and depression on the subjective affective response and amygdala responsiveness to unfamiliar infants using functional magnetic resonance imaging. Smiling infant pictures were used in a 2 × 2 design comparing four groups of women: mothers and non-mothers, with and without depression (total of 101 women: postpartum depression [PPD] = 32, non-PPD = 25, major depression [MDD] = 15, non-MDD = 29). We undertook an anatomically defined region of interest analysis of the amygdala response for a priori defined group comparisons. We found that mothers rated infants more positively than non-mothers and non-mothers rated non-infant stimuli (scenery) more positively than mothers. In the amygdala, we found that depression elevated response to smiling unfamiliar infants in mothers but had no effect in non-mothers. Within the depressed groups, mothers (PPD) showed an elevated amygdala response to unfamiliar smiling infants compared to depressed non-mothers. Hence, our results indicate that women with PPD show an enhanced amygdala response to affectively positive infant pictures but not to affectively positive (but non-salient) pictures of scenery. Women with depression outside of the postpartum period show no change in amygdala responsiveness to either stimulus categories.
在许多哺乳动物物种中，新妈妈在分娩后会对婴儿及其提示表现出更高的积极反应。从非人类和人类研究中可以明显看出，杏仁核是涉及母婴神经回路的大脑区域，并且参与处理社会情感相关的刺激。在人类中，婴儿对女性，尤其是母亲来说是具有社会意义的刺激。研究母亲对婴儿提示的反应的神经影像学研究表明，与婴儿相关的杏仁核功能是母亲焦虑/抑郁、母性质量和母亲动机个体差异的重要因素。本研究使用功能磁共振成像技术，研究了母亲身份和抑郁对陌生婴儿的主观情感反应和杏仁核反应的影响。使用 2×2 设计比较了四组女性：母亲和非母亲，以及有和没有抑郁（共 101 名女性：产后抑郁[PPD]=32 名，非 PPD=25 名，重度抑郁[MDD]=15 名，非 MDD=29 名）的微笑婴儿图片。我们对杏仁核反应进行了预先定义的组间比较的解剖定义感兴趣区分析。我们发现，母亲比非母亲对婴儿的评价更积极，而非母亲对非婴儿刺激（风景）的评价比母亲更积极。在杏仁核中，我们发现抑郁会增加母亲对微笑陌生婴儿的反应，但对非母亲没有影响。在抑郁组中，与抑郁的非母亲相比，母亲（PPD）对陌生微笑婴儿的杏仁核反应增强。因此，我们的结果表明，患有 PPD 的女性对情感积极的婴儿图片表现出增强的杏仁核反应，但对情感积极（但非突出）的风景图片没有反应。产后以外患有抑郁症的女性对两种刺激类别的杏仁核反应均无变化。
