The central feature of episodic memory is that each item to be remembered is associated with a specific context?a time, place, and circumstance. According to the BIC model of MTL function (Diana, Ranganath, &Yonelinas, 2007), three regions in the medial temporal lobes (MTL)?the perirhinal cortex (PRc), parahippocampal cortex (PHc), and the hippocampus?make qualitatively different contributions to the encoding of item information, context information, and the binding of items to episodic context, respectively. Alternative MTL models exist, however the BIC model is unique in its focus on differentiating the roles of the PRc and PHc. PHc function is the least well understood of the MTL subregions. The BIC model makes predictions both for the role of PHc in memory and the cognitive relationships between item and context information that can affect memory. This project will test the BIC model's predictions about the cognitive and neural bases of episodic memory.
Specific Aims : 1) To examine the dynamics of episodic information, in particular how cognitive representations are changed as a result of unitization of item and context information. 2) To test the neural hypothesis that PHc and PRc activations are differentially involved in retrieval of context representations and item representations, respectively. 3) To identify the nature of context information represented in the PHc, testing the neural hypothesis that PHc encodes the internal, mental context of an event.
Memory for past events is critical to most of our daily activities. Impairments in episodic memory in psychiatric (e.g. schizophrenia and depression) and neurological (e.g. Alzheimer's Disease) disorders have a debilitating effect on quality of life. Research into the cognitive and neural bases of episodic memory processes can lay the foundation for new diagnostic and therapeutic approaches to these conditions.
