Barcoding of episodic memories in the hippocampus of a food-caching bird

Episodic memory, or memory of experienced events, is a critical function of the hippocampus. It is therefore important to understand how hippocampal activity represents specific events in an animal's life. We addressed this question in chickadees — specialist food-caching birds that hide food at scattered locations and use memory to find their caches later in time. We performed high-density neural recordings in the hippocampus of chickadees as they cached and retrieved seeds in a laboratory arena. We found that each caching event was represented by a burst of firing in a unique set of hippocampal neurons. These 'barcode-like' patterns of activity were sparse (