Lucid dreams are dreams in which you realize you are dreaming and are having different levels of control over the dream. Lucid dreams are far more grounded and less bizarre than non-lucid dreams. They are highly vivid and easier to slip back into the unconscious state.
Lucid dreaming is being fully aware that you are inside of a dream, and you are actively participating in your dream experience. In a lucid dream, you get to do things you cannot do in a typical dream, and the dream feels more interactive than in a non-lucid dream.
Lucid dreaming differs from normal dreaming in that with lucid dreaming a person is actually aware that they are dreaming while they are dreaming. In most sleep studies, scientists use electroencephalography (EEG) to record brain activity during sleep. They have determined that “lucid dreams are infrequent – less than 1 percent of dreams in most studies”. Normal dreaming happens quite frequently, most often during REM (rapid eye movement) sleep.
But normal dreaming can also occur during non-REM sleep periods. One theory of dreaming is that the cortex of a person’s brain is almost as active during REM sleep as it when a person is awake and it is this “rhythmic burst” of activity that causes dreaming. Another theory is that lower brain stem activity stimulates or activates the cortex which then causes dreaming.