"Semantic Memory and Multi-Trial Learning" by Dr. Lisa Genzel (Radboud University)

On behalf of the 'The Memory Tapestry: Weaving Insights Across Different Systems and Levels' Group, Dr. Lisa Genzel will give a talk titled "Semantic Memory and Multi-Trial Learning" as part of the 2026 Student/Postdoc-Run Speaker Series (SPRSS).

Abstract: Adapting to environmental changes is critical for our survival. The brain’s ability to build up knowledge about the world that enables us to benefit from our previous experience has been a long-standing, central topic in psychology and neuroscience. However, research into the neurobiology underlying knowledge build-up and updating is now just beginning. In my lab we develop new rodent tasks (e.g. Object Space Task and the HexMaze) to tap into how animals’ build-up knowledge from experiences. We also use one session learning tasks (e.g. watermaze) for translation applications in humans and rodents. We combine these tasks with electrophysiology, pharmacology, functional MRI and immediate early gene expression analysis to investigate how memories become long lasting and which role location specific plasticity and sleep has in the process. This approach has revealed surprising results. The hippocampus optimizes but is not necessary for multi-trial memory and the cortex is an independent, fast but adaptive learner. In our semi-naturalistic memory task setting, the 9x5m HexMaze, spatial memory and navigation persist without the hippocampus – only necessary for one-session learning and computations like sophisticated path optimization. These optimizations occur during sharp-wave ripple oscillations, when hippocampal and cortical circuits engage in a bidirectional exchange.