This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The hippocampal formation (hippocampus and entorhinal cortex) is essential for making episodic memories in the mammalian brain. The physical substrate of memory resides in the connections among groups of cells (ensembles) and their dynamic activity (electrophysiological) patterns. This project will use a rodent model to address: 1) whether different parts of the hippocampus and entorhinal cortex interact as a single functional group or alternatively work as separate functional groups and 2) the role of specific electrophysiological patterns (theta and gamma rhythms) in defining the activity of a group. Previous studies demonstrated that changes in theta and gamma coherence, a measure of temporal synchrony among neurons, relates to the strength of episodic memory formation and memory retrieval. A key component of the these studies will be how manipulations of the environment (e.g., novelty) alter theta and gamma coherence and whether theta and gamma coherence varies throughout different parts of the hippocampus and entorhinal cortex. This project will provide knowledge about functional interactions between different parts of the hippocampus and entorhinal cortex and how theta and gamma patterns either bring different parts together or segregate them in relation to specific sensory events. This project will also provide; 1) integrative biology training to high school, undergraduate and graduate students interested in psychology, neuroscience and biomedical engineering and 2) a large in vivo electrophysiological database for experimental and computational neuroscientists interested in hippocampal physiology and memory formation.
