Memory encoding and retrieval: The role of context in recall and recollection

University Of California At Davis, Davis CA

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Abstract

[unreadable] DESCRIPTION (provided by applicant): The ability to remember past events, or episodic memory, is critical to our daily activities. A central feature of episodic memories is that they are associated with a specific context-a time, place, and situation. Indeed, most research in psychology and neuroscience has conceptualized episodic recollection as the retrieval of an association between an item and the context in which the item was encountered. According to a recently proposed model, three regions in the medial temporal lobes (MIL)-the perirhinal cortex (PRc), parahippocampal cortex (PHc), and hippocampus-make qualitatively different contributions to the encoding of item information, context information, and the binding of item information to episodic context, respectively. The specific aims of this proposal are to test two predictions stemming from this model: 1) To test the hypothesis that encoding of context information is dissociable from encoding of item-context associations, both in terms of cognitive performance and electrophysiological activity, and that this context information differentially supports memory retrieval using recognition and recall. 2) To test the hypothesis that the perirhinal cortex (PRc), parahippocampal cortex (PHc), and hippocampus are differentially involved in encoding of item representations, context representations, and representations of item-context bindings Exp. 1 will manipulate contextual uniqueness to determine whether context information can be strengthened independently from item-context associations during encoding. This additional contextual strength should be evident in the ERP subsequent memory effects and is expected to support recall performance but not recollection performance. Exp. 2 will use fMRI scanning during encoding to compare storage of repeated items, repeated contexts, and repeated item-context bindings, allowing dissociation of the areas involved in storage of item information and contextual information. Exp. 3 will also use fMRI scanning during encoding to further investigate the role of parahippocampal cortex in storage of context information, testing encoding of spatial vs. verbal context and task-determined designation of context. Relevance: Impairments in episodic memory in psychiatric (e.g., schizophrenia and depression) and neurological (e.g., Alzheimer's Disease) disorders have a debilitating effect on patients' quality of life. By specifying the neural underpinnings of episodic memory processes, this research can inspire new diagnostic and therapeutic approaches these conditions. [unreadable] [unreadable] [unreadable]