Stress effects on childhood brain development

描述(申请人提供)：这项研究的目标是调查压力对儿童大脑发育的影响。虽然发育期间的低水平压力可以促进晚年的健康应对，但长期的压力会使人容易出现精神障碍，并损害认知。虽然慢性压力不能在人体内进行实验操作，但可以研究压力暴露中自然发生的变化的影响。童年社会经济状况(SES)是一个由父母教育、职业和收入组成的指数，它与接触压力和对压力的反应程度有关。较低的SES与更多的压力生活事件和更严重的压力生理失调有关。此外，低SES环境与缓冲压力影响的因素较少相关。最近的动物研究提供了证据，表明压力可能会加速重要的成熟过程。这是有问题的，因为人类的研究发现，大脑发育较慢与卓越的认知技能有关。我提议测试一个新的假设，即压力会加速幼儿的大脑发育。此外，我将探讨大脑早期成熟是否是对高压力环境的适应性反应的问题。为了检验这些假设，我将招募来自低SES背景、经历过许多压力生活事件的6岁儿童(高压力组，N=40)和来自高SES背景、经历过很少压力生活事件的儿童(低压力组，N=40)。我将1)描述高应激组和低应激组在感知压力、生理应激标记和认知表现上的差异；2)测试高应激组是否表现出更大的结构性大脑成熟度，其指标是更大的皮质厚度和更多的白质定向扩散性；3)探索结构成熟度的差异是否反映在功能网络中；以及4)调查高应激组的早熟是否与较差或更好的认知能力和心理健康有关。在高压力下 在环境中，加速成熟可能是适应性的，因为它保护了处于部分发达状态的支持认知技能的网络，使它们不太容易受到环境的侮辱。总而言之，这项研究将首次检验压力加速幼儿大脑发育这一创新假设，并探索加速发育是否是对压力的适应性反应。这项研究的结果将有助于填补认知神经科学研究中由于来自低SES背景的儿童代表性不足而形成的主要知识空白。我们的发现将阐明童年压力影响认知并增加精神疾病风险的神经发育机制。从这项工作中获得的知识将为干预措施的目的是加速还是减缓暴露在压力下的儿童的大脑成熟提供洞察力。

DESCRIPTION (provided by applicant): The goal of this research is to investigate the effects of stress on childhood brain development. While low levels of stress during development can promote healthy coping later in life, chronic stress sets up vulnerabilities for psychiatric disorders and impairs cognition. Although chronic stress cannot be experimentally manipulated in humans, it is possible to investigate the effects of naturally occurring variations in stress exposure. Childhood socioeconomic status (SES), an index composed of parental education, occupation, and income, is linked to a gradient in exposure and reactivity to stress. Lower SES is associated with more stressful life events and greater dysregulation of stress physiology. Further, low SES environments are associated with fewer factors that buffer the effects of stress. Recent animal research has provided evidence that stress might accelerate important maturational processes. This is problematic in light of the finding in humans that slower brain development is associated with superior cognitive skills. I propose to test the novel hypothesis that stress accelerates brain development in young children. Further, I will explore the question of whether early brain maturation is an adaptive response to a high-stress environment. To test these hypotheses, I will recruit six-year-old children from low SES backgrounds who have experience many stressful life events (high-stress group, N=40), and children from high SES backgrounds who have experienced few stressful life events (low-stress group, N=40). I will 1) characterize differences in perceived stress, physiological stress markers, and cognitive performance between high- and low-stress groups; 2) test whether the high-stress group exhibits greater structural brain maturity as indexed by greater cortical thickness and more directional diffusivity in white matter; 3) explore whether structural maturation differences are reflected in functional networks; and 4) investigate whether early maturation in the high-stress group is associated with inferior or superior cognitive abilities and mental health. In high-stress environments, accelerated maturation may be adaptive because it protects networks supporting cognitive skills in a partially developed state, rendering them less vulnerable to environmental insult. In sum, this research will be the first to test the innovative hypothesis that stress accelerates brain development in young children, and to explore whether accelerated development is an adaptive response to stress. Results of this study will help fill a major gap in knowledge that has evolved from the underrepresentation of children from low SES backgrounds in cognitive neuroscience research. Our findings will elucidate the neurodevelopmental mechanisms by which childhood stress impacts cognition and increases risk for psychiatric illness. Knowledge gained from this work will provide insight into whether interventions should aim to accelerate or decelerate brain maturation in children exposed to stress.