Massachusetts Institute of Technology professor, Matthew Wilson, and Kenway Louie, a graduate student, trained rats to run round a track. They measured that rats' brain activity while they performed the task, and also while the rats were asleep. Some half the rats exhibited the same type of brain patterns while they were asleep as while they were awake. The researchers could even guess what the rats were dreaming about, such as their location and whether they were standing or running. The brain activity was found to be concentrated in the hippocampus, which is linked to memory formation.
Sleep appears to play a role in the way that memories are formed.
Memory formation takes place in two stages, while animals are undergoing experiences, and then through consolidation, which is important for forming long term memories. Other research on the way animals dream backs up these findings on rats. They used four male rats with microelectrodes implanted into their hippocampi. The rats had learnt to run along a track, with food rewards at checkpoints. Patterns of spikes could be seen that could be linked to the rats' location on the track.