Researchers continue to work on our understanding of the aging brain. From EurekAlert!: "During sleep, the hippocampus, a brain region important in learning and memory, repeatedly 'replays' brain activity from recent awake experiences. This replay process is believed to be important for memory consolidation. [Researchers] found reduced replay activity during sleep in old compared to young rats, and rats with the least replay activity performed the worst in tests of spatial memory. [The researchers] recorded hippocampal activity in 11 young and 11 old rats as they navigated several mazes for food rewards. Later, when the animals were asleep, the researchers recorded their hippocampal activity again. In the young animals, the sequence of neural activity recorded while the animals navigated the mazes was repeated when they slept. However, in most of the old animals, the sequence of neural activity recorded during sleep did not reflect the sequence of brain activity recorded in the maze. ... These findings suggest that some of the memory impairment experienced during aging could involve a reduction in the automatic process of experience replay."