Shared and unique properties of place cells in anterior cingulate cortex and hippocampus

In the brain, spatial information is represented by neurons that fire when an animal is at specific locations, including place cells in hippocampus and grid cells in entorhinal cortex. But how this information is processed in downstream brain regions still remains elusive. Using chronic Ca2+ imaging, we examined the activity of neurons in anterior cingulate cortex (ACC), a brain region implicated in memory consolidation, and found neurons that fire in a manner consistent with the properties of place cells. While the ACC place cells showed stability, location and context specificity similar to the hippocampal counterparts, they also have unique properties. Unlike hippocampal place cells that immediately formed upon exposure to a novel environment, ACC place cells increased over days. Also, ACC place cells tend to have additional place fields whereas typical hippocampal place cells have only one. Hippocampal activity is required for the formation of ACC place cells, but once they are established, hippocampal inactivation did not have any impact on ACC place cell firing. We thus identified features of ACC place cells that carry spatial information in a unique fashion.