The goal of this work is to help clarify the contribution of the hippocampus to memory by testing the implications of a recently-developed theoretical framework for understanding the complementary roles of the hippocampus and neocortex in learning and memory. This framework centers around a set of principles derived from computational neural network models, and we have instantiated it in a specific biologically-based model. Many prominent theories of the hippocampus assume that it contributes to memory by storing conjunctive representations of the features that make up a particular experience. However, this idea is too general because there are a number of reports that animals with severe damage to the hippocampus solve problems that require conjunctive representations. The present model recognizes that the cortical system alone can store stimulus conjunctions. However, it is posited that the hippocampal and cortical systems differ along two important dimensions: (a) learning rate-the hippocampal system rapidly stores conjunctions whereas the cortical system learns more slowly, and (b) the task demands under which the two systems are driven to develop conjunctive representations-the hippocampal system has a natural bias to automatically store conjunctions just as a function of the organism sampling the environment, whereas the cortex is not naturally biased to store conjunctions, and only does so when forced to by the demands of a problem (e.g., reinforcement contingencies). As implemented in the present model, these ideas provide a good account of many phenomena in the literature. By comparing rats with damage to the hippocampus and intact rats, and conducting additional simulations, the goal is to evaluate the proposed theoretical framework by testing its implications for: (a) when the hippocampus will contribute to complex nonlinear discrimination problems, (b) understanding how the hippocampus contributes to contextual fear conditioning, (c) the role of the hippocampus in tasks where conjunctions are automatically learned versus those where they must be learned to satisfy the contingencies of reinforcement, and (d) how the hippocampus mediates what some call logical reasoning (transitive inferences). By pursuing these aims, the proposed research will provide a more complete understanding of the role of the hippocampus in memory.

National Institute of Health (NIH)
National Institute of Mental Health (NIMH)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-IFCN-5 (05))
Program Officer
Anderson, Kathleen C
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Colorado at Boulder
Schools of Arts and Sciences
United States
Zip Code
Biedenkapp, Joseph C; Rudy, Jerry W (2009) Hippocampal and extrahippocampal systems compete for control of contextual fear: role of ventral subiculum and amygdala. Learn Mem 16:38-45
Rudy, Jerry W (2009) Context representations, context functions, and the parahippocampal-hippocampal system. Learn Mem 16:573-85
Rudy, Jerry W; Matus-Amat, Patricia (2009) DHPG activation of group 1 mGluRs in BLA enhances fear conditioning. Learn Mem 16:421-5
Huber, David E; Tian, Xing; Curran, Tim et al. (2008) The dynamics of integration and separation: ERP, MEG, and neural network studies of immediate repetition effects. J Exp Psychol Hum Percept Perform 34:1389-416
Atallah, Hisham E; Rudy, Jerry W; O'Reilly, Randall C (2008) The role of the dorsal striatum and dorsal hippocampus in probabilistic and deterministic odor discrimination tasks. Learn Mem 15:294-8
Serrano, Peter; Friedman, Eugenia L; Kenney, Jana et al. (2008) PKMzeta maintains spatial, instrumental, and classically conditioned long-term memories. PLoS Biol 6:2698-706
Rudy, Jerry W; Sutherland, Robert J (2008) Is it systems or cellular consolidation? Time will tell. An alternative interpretation of the Morris group's recent science paper. Neurobiol Learn Mem 89:366-9
Biedenkapp, Joseph C; Rudy, Jerry W (2007) Context preexposure prevents forgetting of a contextual fear memory: implication for regional changes in brain activation patterns associated with recent and remote memory tests. Learn Mem 14:200-3
Matus-Amat, Patricia; Higgins, Emily A; Sprunger, David et al. (2007) The role of dorsal hippocampus and basolateral amygdala NMDA receptors in the acquisition and retrieval of context and contextual fear memories. Behav Neurosci 121:721-31
Bolding, Kevin; Rudy, Jerry W (2006) Place learning in the Morris water task: making the memory stick. Learn Mem 13:278-86

Showing the most recent 10 out of 23 publications