The bursts of brain activity known as sleep spindles play a vital role in strengthening new memories. Scientists have long known that sleep spindles play an important role in the formation and retention of new memories. Sleep spindles are half-second to two-second explosions of brain activity that occur during deep sleep and can be visualized and measured on an electroencephalogram.

Every day, we have four or seven long dreams, even though it may seem incredible, that is the reality, all human beings dream several times during the same night; however, we forget practically 90% of those dreams a few minutes after waking up.

In the film Oblivion: "The Time of Forgetting" (2013), the main character Tom Cruise, playing Jack Harper, lives in a story similar to the one told in this novel. He doesn't remember the past very well, he believes he lives between dream and reality until he finally discovers that there are copies of it, with its essence.