Infant Cortisol Reactivity and its Relationship to Learning and Memory

描述（由申请人提供）：本研究将通过研究不同因素如何影响幼儿在学习情境中肾上腺皮质反应的方向和程度，为婴儿认知发展这一研究尚不充分的课题做出贡献。皮质醇是一种肾上腺类固醇激素，在身体和情绪压力下分泌，也与高觉醒状态有关。我们之前的研究表明，那些在母亲分离/学习事件中表现出皮质醇下降的婴儿对目标刺激表现出学习和记忆能力。考虑到情绪和认知过程的控制都位于共同的大脑区域，皮质醇反应性下降和更好的学习/记忆之间的联系是预期的结果。然而，我们之前的结果与其他一些关于肾上腺皮质与婴儿认知功能之间关系的研究不一致。本实验的主要目的是通过探索几个可能影响学习事件中皮质醇反应方向的因素，包括生理活动、社会情绪困扰和母亲协助婴儿情绪调节的努力，来确定不同研究之间差异结果的本质。计划进行两项短期纵向研究。将收集这些婴儿年龄（2个月、3个月和6个月）的母婴配对数据。将从婴儿和母亲身上采集唾液皮质醇样本，以评估皮质醇对分离/学习事件反应的方向和程度。婴儿将参加四个实验，旨在评估婴儿对语言和声音刺激的学习和记忆的各个方面。在第二组实验中，母亲将接受训练，表现出旨在帮助婴儿调节肾上腺皮质反应模式的行为。据预测，这种母亲敏感性训练将促进婴儿更好的学习和记忆。行为同步性将通过观察母亲和婴儿在短互动期间的特定行为来测量，每隔10秒观察一次。我们将继续在相关文献中未被充分代表的人群中调查这些关系。这项研究将为研究婴幼儿认知加工、母婴肾上腺皮质功能和照顾者对婴儿的敏感性之间的关系的文献提供有价值的数据。

DESCRIPTION (provided by applicant): This study will make contributions to a very under-researched topic of infant cognitive development by examining how various factors affect the direction and degree of adrenocortical response in young infants in learning situations. Cortisol, an adrenal steroid hormone, is secreted in response to physical and emotional stress and is also associated with high states of arousal. Our previous research showed that those infants who exhibited declining cortisol during a maternal separation/learning event showed learning and memory for the target stimuli. A link between declining cortisol reactivity and better learning/memory was the expected outcome given the argument that the control of both emotion and cognitive processes resides in common brain areas. However, our previous results were inconsistent with some other investigations of the relationship between adrenocortical and infant cognitive functioning. The primary aim of the proposed experiments is to ascertain the nature of the differential results across studies by exploring several factors hypothesized to affect the direction of cortisol reactivity during learning events, including physiological activity, socioemotional distress, and maternal efforts to assist infant emotional regulation. Two short longitudinal studies are planned. Data will be collected on mother-infant pairs at these infant ages: 2 months, 3 months, and 6 months. Salivary cortisol samples will be taken from the infant and the mother to assess the direction and degree of cortisol reactivity to a separation/learning event. Infants will participate in four experiments, designed to assess various aspects of infant learning and memory for language and voice stimuli. In a second set of experiments, mothers will be trained to exhibit behaviors intended to assist their infants in regulating their adrenocortical response patterns. It is predicted that this maternal sensitivity training will promote better learning and memory in infants. Behavioral synchrony will be measured by observing specific behaviors of the mother and infant in 10-sec intervals across a short interaction period. We will continue to investigate these relationships in a population that is underrepresented in the related literature. The research will add valuable data to the literature on the relationship between cognitive processing in infancy, adrenocortical functioning in mothers and infants, and sensitivity of the caregiver to the infant.