All animals possess the ability to form memories. In mammals, the hippocampal memory system is a conglomerate of brain structures that function together to support memory formation. In doing so, this memory system associates, or binds together, people, items, and places into what are known as episodic memories. Episodic memories afford species the ability to remember vital information that increases the likelihood of survival, such as securing long-term food sources. In this example, the animal must remember "what" was stored, "where" it was stored, and "when" it was stored to retrieve the food before it spoils and avoid illness in the process. Within the hippocampal memory system, the predominant role of one structure, called the perirhinal cortex, is to supply a representation of "what" information (e.g., what food item was stored). The perirhinal cortex also appears to be involved in complex stimulus representations outside of its role in episodic memory; however, how and under which circumstances the perirhinal cortex is involved in stimulus representation is currently under debate. This project assesses how the perirhinal cortex functions in a perceptual-specific versus a memory-specific manner in its representation of item information. In addition, the project examines whether the role of the perirhinal cortex in stimulus representation involves connections with structures outside of the hippocampal memory system. Results will furnish significant insight into the contributions of the perirhinal cortex to stimulus representation and how it may differ or complement its well-established role in episodic memory within the hippocampal memory system. All components of the research program provide training opportunities to students at California State University-Sacramento, a minority serving and primarily undergraduate institution. Additionally, outreach events provide students with opportunities to increase STEM-awareness in the community.
Currently, it is debated how the perirhinal cortex may function in stimulus representation, and if this function is independent from its mnemonic role within the hippocampal memory system. This project uses an associative learning paradigm (Pavlovian fear conditioning) in combination with an innovative inactivation method, Designer Receptors Exclusively Activated by Designer Drugs, and cross-lesion techniques to evaluate the functional role of the perirhinal cortex in stimulus representation. Specifically, using the laboratory rat as a model system the project aims to: 1) examine the characteristics of stimuli that require the perirhinal cortex for stimulus representation; 2) determine whether the role of perirhinal cortex in stimulus representation is perceptual, mnemonic or a combination; and 3) determine whether in stimulus representation the perirhinal cortex relies on direct connections with structures outside of the hippocampal memory system. The research project provides extensive training opportunities to students at California State University-Sacramento, which is a minority serving and primarily undergraduate institution. Further, community outreach, which includes events that expose elementary school girls to science, promote university-wide brain awareness and present research findings to the local community, provide students with opportunities to increase STEM-awareness in the broader community.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
