Tom dreams of Jerry

Research on memory formation and dreaming in rats

source: Alison Motluk
New Scientist February 3 2001 p19

Matthew Wilson and Kenway Louie from Massachusetts Institute of Technology have carried out research on rats' neuronal activity while performing a task, and while asleep. 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. The rats were also monitored when they were asleep, and their brain activity during REM sleep was found to resemble their activity while on the track on 50 per cent of the recording sessions. The memories were replayed at the same speed as the original experiences. Wilson argues that his work shows that animals can re-evaluate experiences while asleep, and he believes that mamories may be laid down in REM sleep through animals reactivating experiences. Dreams may allow animals to bring together related experiences occurring at different times. This work was reported in 'Neuron', vol 29 p145.