Retrieval Processing in Human Memory: ERP and fMRI Investigations

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DESCRIPTION (provided by applicant): The capacity to acquire and retrieve memories of unique events is termed 'episodic memory'. Disabling impairments of episodic memory are prominent in several common neurological conditions, including Alzheimer's disease and Traumatic Brain Injury, and it has been proposed that episodic memory dysfunction plays a role in common psychiatric disorders such as post-traumatic stress disorder and depression. The characterization of episodic memory impairment and dysfunction, and the development of rational remedial measures, require an understanding of the cognitive operations that support episodic memory and their neural underpinnings. The proposed research will contribute to this understanding through a cognitive neuroscience investigation of two aspects of episodic memory retrieval: the processes engaged i) when a cue is employed in an attempt to retrieve episodic information from memory, and ii) when a retrieval attempt is successful. The research will combine behavioral methods with two methods for non-invasive measurement of brain activity, event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI). Together, the methods will be employed to further understanding of cue processing and successful episodic retrieval. With regard to cue processing, issues to be addressed include: the circumstances under which individuals can bias cue processing (adopt a 'retrieval orientation') in service of a specific retrieval goal; the neural correlates of the maintenance of specific retrieval orientations; and the functional significance of differential neural activity elicited by cues employed in service of different retrieval goals. In the case of successful retrieval, issues include: the enerality of previously described neural correlates of episodic retrieval; the sensitivity of these neural correlates to the content and amount of information retrieved; and comparison of existing recognition-based procedures for investigating episodic retrieval to results obtained with a recall procedure.