Lucid dreaming is a phenomenon in which dreamers are aware they are dreaming, and may be able to exert some control over dreams. During lucid dreaming, higher levels of activity are detected in the frontal and frontolateral (executive) regions of the brain than during nonlucid REM sleep. Lucid dreamers typically report greater awareness about the unreality of dream objects and characters and greater awareness of their sleeping physical body.
Austrian neurologist Sigmund Freud proposed that dreams are the result of unconscious processes expressing hidden desires, fears, and wishes a person finds threatening or unacceptable while awake. Freud distinguished between a dream's manifest content (its apparent topic or superficial meaning) and latent content (its true underlying meaning). For example, a common dream among college students involves discovering they are naked while giving a presentation in a classroom full of people. The manifest content is being naked in front of a room full of people. The latent content might be fear of exposure, namely fear that people will realize the dreamer is inadequate or a fraud. The problem with Freud's theory is that it is not systematically testable and therefore lacks scientific support. Any dream can be interpreted in several ways, and it is impossible to determine which interpretation is correct.Another dream theory is the activation-synthesis model, which proposes dreams are produced when the brain attempts to make sense of random neural activity. During waking consciousness, the brain receives input from the external world. It uses that information along with stored knowledge to assign meaning to experiences. During dream consciousness, the brain receives information from internal neural activity. That internal neural activity may be totally unrelated to external reality, yet the brain still tries to assign meaning. The side effect of this neural processing is a jumble of dream events that are not logically related.