BMI Special Seminar // Tristan Geiller: Functional organization of hippocampal output circuits for learning and memory: focus on the Subiculum

Since the mid-20th century, observations from human patients and the discovery of neural representations such as place cells have placed the hippocampus at the center of investigations into learning and memory. In rodent models, decades of work have revealed an extraordinary richness in hippocampal physiology, from synapses and interneurons to population dynamics. Despite this progress, much of this knowledge has been derived from studies mostly within defined hippocampal subregions, and we still lack a basic understanding of how hippocampal signals propagate beyond the hippocampus itself. In particular, the cellular, synaptic, and circuit mechanisms by which hippocampal activity is integrated, transformed, and routed to downstream structures remain poorly defined. In this talk, I focus on the subiculum, the major output structure of the hippocampus, as a model pathway to address these gaps across synapses, cells, and circuits. I show how this multi-scale approach provides new insights into how hippocampal activity can be filtered, stabilized, and selectively routed to support cognition and complex behavior.