As a visiting Fellow, Edvard Moser enriched the Berlin research community. In cooperation with the laboratory of Prof. Dietmar Schmitz, they investigated neuronal circuits in the hippocampal and para-hippocampal formation. This brain system is central to the two interrelated cognitive domains of spatial navigation and memory. Their main focus was on neuronal circuits in the parasubiculum, a somewhat enigmatic hub in the hippocampal formation.
In addition, their cooperation sesulted in some groundbreaking work on local circuits in the CA3 region of the hippocampus. Their description of connectivity in this region is the quantitative foundation for models of learning and memory in this brain region. In addition, a newly developed disruptive technology developed in the Moserlab, the so called "Mini2P" was succesfully transferred to Berlin. Two-photon (2P) microscopy is the gold standard for intravital dynamic microscopy in the rodent brain. However, a normal 2P microscope has a spatial footprint in the squaremeter range and weighs 10s of kilogramms, which means that it is build around a head-fixed mouse. The Mini2P uses a radically new design principle that shrinks this footprint to several square millimeters and reduces the weight to 2g. This microcope can be mounted on a mousehead, making it for the first time possible to perform 2P imaging in freely moving mice to study navigation under realistic conditions.