Download 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.