Multiple mechanisms for memory replay

Cast your mind back to your childhood. A stream of mental images of events and places appears, like photographs in an album. How do our brains capture and preserve these episodes, and then vividly recall them at will many years later? On page 184 of this issue, O'Neill et al. ( 1 ) show that a region of the brain called the medial entorhinal cortex can replay waking experiences. Their work thus challenges the prevailing view that the hippocampus is the sole initiator of spatial and episodic memory reactivation.