If you fall off a bike, you'll probably end up with a cinematic memory of the experience: the wind in your hair, the pebble on the road, then the pain. That's known as an episodic memory. Researchers have identified cells in the human brain that make this sort of memory possible, a team reports in the journal Proceedings of the National Academy of Sciences. The cells are called time cells, and they place a sort of time stamp on memories as they are being formed. That allows us to recall sequences of events or experiences in the right order.