The research was conducted by scientists from the Norwegian University of Science and Technology’s (NTNU) Kavli Institute for Systems Neuroscience and Centre for Neural Computation along with colleagues from the Czech Republic and Italy. The team included NTNU Professor and 2014 Nobel Laureate May-Britt Moser. They tested the ability of rats to remember a number of distinct but similar locations. Their findings are published in the Proceedings of the National Academy of Sciences.
The researchers tested memory in seven laboratory rats by letting them run around in 11 distinct yet similar rooms over the course of two days. The freely running rats wandered around the rooms in pursuit of chocolate crumbs while researchers recorded brain activity in CA3 place cells in the hippocampus. As their name suggests, place cells are neurons that fire in a specific place.
The rooms were very alike, but the rats still managed to create a separate, independent memory, or a map for every environment, the researchers found. These unique representations or firing patterns were stored in the rats’ memories so that when the animal was introduced to one of the rooms a second time, the spatial map from the rat’s first exposure to the room was reactivated.
“We investigated whether these memories overlapped across some rooms, but all of the memories were completely independent,” said the paper’s first author, Charlotte Alme. “This indicates that the brain has an enormous capacity for storage. The ability to create a unique memory or map for every locale explains how we manage to distinguish between very similar memories and how the brain prevents us from mixing up events.”
