Hippocampal place cell recordings in a Four-Room navigation task

Hippocampal place cells show location-specific firing and are thought to be an essential component of the brain’s “cognitive map”, supporting flexible memorization of places and possibly of their connectivity. So far, only a few studies investigated whether these cells encode the connectivity between places, either by adding a barrier or removing a wall. We aimed to go one step further and investigated whether place cells can encode pure connectivity, i.e. changes in the “closed” or “open” aspect of an otherwise identical door. We performed extracellular tetrode recordings from the dorsal CA1 hippocampus of 5 male Lister-Hooded rats while they were foraging and navigating in a 4-compartment environment. Pushable doors were used by the rats to transition between compartments. At first, all 4 doors were pushable. In a test condition, either one of the doors was closed, or all of the doors were closed one-way. This data could be analysed further to investigate basic place cell firing properties as well as possible neural correlates of navigation in such an environment.