Studies have shown that after having about 90% of their dentate gyrus cells destroyed, rats had extreme difficulty in maneuvering through a maze they had previously negotiated. When being tested a number of times to see whether they could learn a maze, the results showed that the rats did not improve at all, indicating that their working memories were severely impaired. Rats had trouble with place strategies because they could not consolidate learned information about a maze into their working memory, and, thus, could not remember it when maneuvering through the same maze in a later trial.