Hippocampal impact on prefrontal cortex: basic mechanisms of memory consolidation

• Applicants: Professor Dr. Andreas Draguhn; Professor Dr. Martin Korte
• Subject Area: Molecular Biology and Physiology of Neurons and Glial Cells ; Cognitive, Systems and Behavioural Neurobiology
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 272381392

Memory formation is a key function of all higher nervous systems, and research on cellular and molecular mechanism of neuronal plasticity is highly advanced. At the level of networks, our knowledge is still less advanced. One of the best studied model systems is spatial memory formation in the entorhinal-hippocampal system of rodents, where we know much about spatially tuned spike patterns and their organization by different types of network oscillations. On a larger scale, long-term consolidation of memories involves coordinated activity between the hippocampus and neocortical areas, especially the prefrontal cortex. The cellular and network mechanisms of this interaction are, however, unknown. We want to explore information transfer from hippocampal to prefrontal networks, with focus on plasticity. We suggest that signaling from hippocampal to prefrontal networks is strongly state-dependent. We will therefore induce different patterns of hippocampal activity in vitro and in vivo, and measure their impact on prefrontal neurons. We will then proceed to the network level and observe multicellular activity patterns in the prefrontal cortex, asking how these patterns are affected by hippocampal input signals. In order to study hippocampus-induced plasticity, inputs to the prefrontal cortex will be stimulated with LTP/LTD-paradigms. The impact will be measured both at the cellular as well as at the network level. Finally, experiments in living animals shall reveal the state-dependence of coupling between oscillating networks in both regions. For causal analysis, hippocampal afferents will be specifically manipulated using electrical and optogenetic methods. Together, our experiments shall elucidate how hippocampal networks affect prefrontal activity patterns in a state- and activity-dependent manner. They shall, therefore, make an important contribution to present concepts of memory consolidation.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Jurij Brankack