Role of the Hippocampus and its Projections in Episodic Memory Development

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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.