The Nature and Functions of Sleep and Dreams

The Nature and Functions of Sleep and Dreams There is no right or wrong process for looking at dreams   Experiments and theories have been created, but so far there is no correct method of interpreting and understanding why we dream. At the present, we can take ideas from all of the theories to mold a better understanding of dreaming. Discovery of REM sleep     Up until the 1950s “people thought that sleep was simply a state of reduced activity that occurred by default when activation subsided. Rather, sleep is an actively induced, highly organized brain state.” In the 1950s Nathaniel Kleitman and his graduate students Eugene Aserinsky and William Dement discovered REM (rapid eye movement) sleep. REM led to further discovery of sleep cycles REM sleep discovery changed the public’s view of sleeping and the validity of scientifically studying the nature of sleep Sleep cycles      Throughout the night humans pass through a sleep cycle consisting of 5 stages lasting 90 to 100 minutes. Stage 1: Slow breathing and irregular brain waves. Stage 2: Bursts of rapid, rhythmic brain wave activity Stage 3: Transitional stage Stage 4: Deep sleep REM sleep     REM sleep: associated with most vivid dreaming Brain waves during REM sleep closely resemble that of awake subjects Studies show that when awakened from REM sleep a subject is 75% more likely to remember dreams compared to the 10% who remember dreams when woken during non-REM sleep Dreams during REM sleep are more vivid and life-like compared to simple images of non-REM sleep Why do we sleep?      Sleep has persisted during the evolution of humans suggesting reason for importance Sleep deprivation is followed by rebound sleep Functional impairments following sleep loss also hint at the significance of sleep “All rats chronically deprived of sleep by an automated apparatus died after about 2 to 3 weeks” The importance of sleep is apparent, however there is no common agreement on why it is vital. Freud’s Interpretation      The Interpretation of Dreams, by Sigmund Freud published in 1900, stated that dreams are a key component for comprehending the inner conflicts of humans Manifest content – incorporated segments of daily life Latent content – unconscious wishes and wants hidden deep within an individual According to Freud, unacceptable wishes find release when transformed by the brain into a more acceptable, subconscious form (ex. gun = penis) We don’t have enough research to prove Freud’s claims are entirely true. Different Interpretations    There are many different interpretations of dreams Anthony Shafton found 24 different interpretations of a single dream “Integrating dream interpretation into counseling can promote client development, understanding and selfefficacy.” (Marszalek III & Myers, 2006) Memory     One modern theory: dreaming helps preserve memory During dreaming the brain makes connections with old memories and mixes them with recently experienced material (day residue) Dreams combine different people, places and parts of our lives enabling the dreamer to reinforce short and long term memories The brain regions on rats that buzz during navigation of a maze also buzz during REM sleep Physiological Functions    Dreaming serves as a physiological function because of constant brain activity (2) Stimulating and repeating thoughts and experiences during sleep help to develop and preserve neuronal pathways crucial for learning and motor movements. Infants spend a lot of time in REM sleep, giving researchers reason to believe dreaming and sleep play important roles in development Data from Roffwarg et al., Ontogenetic development of the human sleep-dream cycle, Science, 152:604-619, 1966 Activation-synthesis theory       by Allan Hobson and Robert McCarley in 1977 “Dreams are the brain’s interpretation of its own activity” and “its reaction to random, biological processes that occur during sleep” Dreams are the random events caused by neurons firing randomly during sleep The brain forms a storyline with information taken from memory in an attempt to make sense of what it has experienced (ex. Seeing a cat and dreaming of a lion) The original 1977 theory denied that dreams have meaning or are related to real world environments which eliminates the need to interpret or understand them. In response to criticism Hobson acknowledged that dreams do reflect past memories, fears, hopes, and desires (1988). Conclusion    There is no concrete data significant enough to prove a single function of dreaming. Dreaming is a considerably young field and was not considered academically respectable until 1953 (discovery of REM sleep) Dreaming helps to keep humans functioning, provides opportunities to enhance our neuronal connections, prepares us for waking challenges and informs us of our inner selves. References 1. 2. 3. 4. 5. 6. 7. 8. Rechtschaffen, A., & Siegel, J.M. (2000). Sleep and dreaming. Principles of Neuroscience (4th ed,). 936-947. Myers, D.G. (2004). Psychology (7th ed.). Michigan: Worth. Walker, M.P. (2006) Sleep to remember: the brain needs sleep before and after learning new things, regardless of the type of memory. Naps can help but caffeine isn't an effective substitute. American Scientist, 94.4, 326. Retrieved October 24, 2006, from Expanded Academic ASAP. Shafton, A. (1995). Dream Reader. New York: State University of New York Press. Hartmann, E. (1996). Outline for a theory on the nature and functions of dreaming. Dreaming, 6.2. Retrieved October 31, 2006, from http://www.asdreams.org/journal/articles/62hartmann.htm Louie, K., & Wilson, M.A. (2001). Temporarily structured replay of awake hippocampal ensemble activity during rapid eye movement sleep. Neuron, 29, 145-156. Mendham, T. (2005). The activation-synthesis theory of dreams. Retrieved October 24th, 2006, from http://www.here-be-dreams.com/psychology/activation.html Van de Castle, R.L. (1994). Our Dreaming Mind. New York: Ballantine Books.