Where as dementia and stroke affect only fraction of the population, there is a type of brain dysfunction that will affect all of us-if we live long enough: normal aging. As we age, the anatomical and functional integrity of our brain declines, and so do our cognitive abilities. Even if relatively mild, this decline affects a large number of people, and hence, it has a great impact at the population level. The development of any rational remedial approach depends on a clear understanding of the effects of healthy aging on the neural basis of cognition. Moreover, this knowledge is critical for research on the devastating effects of Alzheimer's disease. The proposed research will contribute to this knowledge by directly linking age-related deficits in memory abilities to age-related deficits in brain anatomy and function. The approach integrates 3 methodological approaches that have been seldom combined in the past. First, we will use functional MRI (fMRI) to measure changes in brain activity as a function of aging. We expect to find not only age-related decreases in activity signaling cognitive deficits, but also age- related increases in activity signaling compensatory mechanisms in the aging brain. Second, we will use diffusion tensor imaging (DTI) to measure the effects of aging on white-matter integrity, as there is evidence that aging impairs not only individual brain regions but also the connections between them. Finally, we will use a comprehensive batter of standardized tests to identify individual differences in neuropsychological status within the aging population. One of the cognitive functions most affected by healthy (and pathological) aging is episodic memory, which refers to memory for personally experienced past events. We propose several fMRI studies to investigate the effects of aging on brain activity associated with recovery of episodic information (episodic retrieval). We will investigate activity in a number of brain regions (prefrontal regions, medial temporal regions, etc) and the interactions among these regions, while young and older participants retrieve new episodic information in the scanner. In particular, we will identify age effects on specific episodic retrieval processes, including generation, familiarity, recollection, and monitoring. In sum, the results of the proposed studies will clarify the neural correlates of age-related deficits in episodic retrieval, and will have important implications for the promotion of health. They will help develop cognitive training methods and will provide an essential baseline for research on Alzheimer's disease.
As we age, our brain declines as do our cognitive abilities. The development of any rational remedial approach depends on a clear understanding of how aging affects the neural basis of cognition. This project investigates age effects on the neural mechanisms of the form of memory most affected by aging: episodic memory.
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