Remembrance of futures past

Much behavioural and physiological evidence suggests that the hippocampus encodes space. Puzzlingly, however, hippocampal damage also disrupts episodic memory. A recent study shows how these two faculties might be related, finding that the spatial firing of hippocampal 'place cells' is sometimes modulated by what the animal has recently done or what it will do next. Thus, the cells encode something resembling a context, or episode, collectively forming a potential substrate for episodic memory.