Role of the Hippocampus and its Projections in Episodic Memory Development

描述(申请人提供)：情节记忆，或有意识地记住过去事件的能力，是人类经验的核心。在许多精神健康障碍中，这种形式的记忆是认知功能受损最严重的之一。在精神分裂症的情况下，间歇性记忆障碍发生在全面疾病发作之前，并预测长期的功能结果。在典型的发育中的儿童中，情节记忆在童年时期改善很快，然后在青春期改善得较慢。支持这些改进的大脑机制尚不清楚。神经科学研究表明，海马体在情节记忆中起着重要作用，支持将事件的不同方面联系在一起的表征的形成和提取。相比之下，外侧前额叶皮质被认为在情景记忆中发挥支持作用，通过向海马体的远程投射控制相关记忆的策略性编码和提取。长期以来，人们一直认为，依赖海马体的结合机制在儿童早期就已经存在，在儿童中期及以后观察到的情景记忆的巨大变化是由于前额叶皮质的长期发育造成的。这项拟议的研究挑战了这一观点，将调查海马体的变化--以及投射到海马体的特定区域的变化--是否以及如何有助于情节记忆的发展。这项拟议的研究将检查大脑结构和大脑功能的个体内部变化，这些变化是8岁至14岁情景记忆表现变化的基础。为此，180名典型发育儿童的样本将在5年内进行三次测试。与发展认知神经科学中的横断面研究相比，这种纵向研究方法将能够识别大脑结构、脑功能和情景记忆变化的前因和后果。与公共卫生的相关性：拟议的研究将为未来对精神分裂症等精神健康障碍的研究奠定基础，对精神分裂症来说，非典型的海马体发育可能是疾病发病的早期指标。

DESCRIPTION (provided by applicant): Episodic memory, or the ability to consciously remember past events, is central to the human experience. In a number of mental health disorders, this form of memory is among the most severely impaired cognitive functions. In the case of schizophrenia, episodic memory dysfunction precedes the onset of the full-blown disorder and predicts long-term functional outcomes. In typically developing children, episodic memory improves rapidly during childhood, and then improves more slowly during adolescence. The brain mechanisms supporting these improvements are not yet understood. Neuroscientific research has shown that the hippocampus plays a fundamental role in episodic memory, supporting the formation and retrieval of representations that bind the different aspects of an event. By contrast, lateral prefrontal cortex is thought to play a supportive role in episodic memory, controlling the strategic encoding and retrieval of relevant memories through long-range projections to the hippocampus. It has long been assumed that the hippocampus-dependent binding mechanism is already in place by early childhood, and that the large changes in episodic memory observed during middle childhood and beyond result from the protracted development of the prefrontal cortex. Challenging this view, the proposed research will investigate whether and how changes in the hippocampus - as well as changes in specific tracts that project to the hippocampus - contribute to the development of episodic memory. The proposed research will examine the within-individual changes in brain structure and brain function that underlie changes in episodic memory performance from age 8 to 14 years. To this end, a sample of 180 typically-developing children will be tested three times over the course of 5 years. As compared with cross- sectional research, which is the norm in developmental cognitive neuroscience, this longitudinal approach will enable the identification of the antecedents and consequences of changes in brain structure, brain function, and episodic memory. Relevance to Public Health: The proposed research will lay the foundation for future research on such mental health disorders as schizophrenia, for which atypical hippocampal development may be an early indicator of disease onset.