The realm of sleep and dreams has long been associated with strangeness, omens, symbols, unconscious impulses and fears. But this sometimes disturbing world of inner turmoil, fears and desires is grounded in our day-to-day experience. The structure and content of thinking looks very much like the structure and content of dreaming. They may be the product of the same machine. Dreams allow the brain to work through its conscious experiences. During dream, the brain appears to apply the same neurological machinery used during the day to examine the past, the future and other aspects of a person’s inner world at night. Memory is the manifestation of this inner world.
What we remember is the result of dreams rather than the other way around. Vivid dreams often occur during REM sleep, named for the rapid eye movement associated with it, however, non-REM sleep also brings dreams but they are more fragmentary. Dreams help people learn. In a study published in the journal Current Biology in April 2010, the study subjects who entered non-REM sleep and dreamed about a video game maze they had played hours earlier saw their performance increase dramatically more than those who slept but did not report any maze-related dreams. Meanwhile, thinking about the maze while awake did not improve the players’ performance.
Although this work focused on non-REM sleep, incorporation of learning happens in all stages of sleep. In deep sleep, the brain is trying to extract meaning from the experience earlier in the day. Individual neurons in humans’ hippocampus fire in response to spatial location. In the future, science may develop ways to control cognitive functions enhanced by sleep, using sleep and dreams as a tool the way we use learning and teaching while we are conscious.
No one can speak to the value of sleep more than someone deprived of it. Alan Berliner, a filmmaker who explored his own insomnia in his 2006 documentary "Wide Awake" offered this perspective to the discussion. "Every night when I put my head on the pillow, it’s like an adventure,” Berliner says in a clip of the film played during the discussion. He described songs, particularly Leonard Cohen’s "In My Secret Life," looping in his head and his thoughts racing uncontrollably. I started to think the expression human error means sleepiness," he said in the film.