Sleeping and Dreaming
Circadian Rhythm
• The pattern of fluctuations in bodily processes
that occur regularly each day.
– Includes; sleep-wake cycles, body
temperature, hormonal secretions, blood
pressures and heart rate.
– These patterns are synchronized with the
24 hour cycle of day and night
Suprachiasmatic Nucleus (SCN)
• This part of the hypothalamus known as the
SCN regulates our sleep-wake cycles.
• The SCN regulates the pineal gland which
releases the hormone melatonin.
Melatonin
• Melatonin helps regulate the body’s sleepwake cycle.
• Exposure to darkness during evening hours
activates the production of melatonin, making
us sleepy.
• During light exposure, melatonin production
falls off, which keeps us awake.
Sleep Hours by Age
Age and Condition
Average Amount of Sleep per
Day
Newborn
Up to 18 hours
1-12 months old
14-18 hours
1-3 years old
12-15 hours
3-5 years old
11-13 hours
5-12 years old
9-11 hours
Adolescents
9-10 hours
Adults, including elderly
7-8(+) hours
Pregnant women
8(+) hours
Things that affect our sleep patterns
• Cloudy Days- lack of light increases melatonin
levels, making us sleepy.
• Time changes- People may feel sluggish during
the first few days after time changes (forward
or backward).
• Frequent time shifts- Frequent time shifts can
throw off the circadian rhythm
Jet Lag
• Change in local time conflicts with your
internal body clock
• Fall asleep earlier than usual (traveling from
east to west).
• Associated with irritability, fatigue, difficulty
concentrating, diarrhea, headache, mild
depression.
• Recovery can take one day per time zone
crossed.
Stages of Sleep
Sleep Stage
Alert wakefulness
Relaxed wakefulness
Stage 1 sleep
Stage 2 sleep
Stage 3 sleep
Stage 4 sleep
REM sleep
State of focused attention or
active thought
Stages of Sleep
State of resting quietly w/ eyes
closed
Light sleep from which the
person can be easily awakened
Deeper sleep, but the sleeper is
still readily awakened
Deep sleep from which it is
difficult to arouse sleeper
Deepest level of sleep
Sleep in which the brain becomes
more active but muscle activity is
blocked; stage associated with
dreaming.
Functions of Sleep
• Protective: Keep you out of harm’s way (esp.
animals)
• Conserve Energy: Lower body temp. at night
helps keep body temp. up during the day.
• Restorative: Replenish proteins and help brain
recover from wear and tear of the day.
Functions of Sleep
• Consolidation: Newly formed memories can
be turned into lasting remembrances.
• Fight Disease-causing Agents: More
susceptible to common ailments due to lack of
sleep
Functions of Dreams
• REM sleep is consolidating fresh memories
into lasting ones (Huber et. al.).
• Dreams help us sort through everyday
problems and concerns (Hartmann).
• Activation-synthesis Hypothesis: Dreams
represent an attempt by the cerebral cortex to
make sense of the random discharges of
electrical activity that occur during REM sleep.
Activation-Synthesis Hypothesis
• According to this, the cerebral cortex creates a
story line based on the individual’s store of
knowledge and memories to explain the
random signals and emotions and sensory
experiences they generate.
Parts of Brain
• Areas in the brainstem that involve emotions,
memory and visual processing are activated
during REM sleep.
• Areas of the brain involved in logical thought
show decreased activity during REM sleep.
• This is why dreams may lack order or ordinary
conscious thought.
Freud
• Believed dreams represent a form of wish
fulfillment.
• Dreams contain symbols that represent the
sleeper’s underlying wishes, usually of a
sexual or aggressive nature.
• Called dreams, the “royal road” to the
unconscious mind, but you need a
psychological road map to determine their
true meanings.
Types of Dream Content
• Freud distinguished between 2 types of dream
content.
–Manifest Content: Manifest content
refers to events that occur in the
dream.
Types of Dream Content
– Latent Content: The true, underlying
meaning of the dream, disguised in the
form of dream symbols.
–The disguise conceals the dream’s real
meaning, helping you stay asleep
instead of being awakened by
emotionally threatening material.
Example
• Manifest Content: Having a dream where you
get pulled over by a police officer for speeding
and receive a ticket.
• Latent Content: Driving fast may symbolize an
unacceptable sexual wish. The police officer, a
symbol of authority, might represent your
father punishing you for having the sexual
wish.
More Freud
• Phallic objects like; trees, skyscrapers, snakes,
and guns are symbols of male genitalia.
• Enclosed objects like; boxes, ovens, closets are
symbols of female genitalia
• Sometimes though, “a cigar is just a cigar”…
Lucid Dreaming
• Lucid dreams are dreams in which the person
is aware that they are dreaming.
• Relatively few people report experiencing
lucid dreams regularly.
• Some people claim to be able to control what
they will dream about and direct the action of
their own dream.
Sleep Deprivation
• Most people need between 7-9 hours of sleep
to feel fully rested. (Americans-6.9)
• 1 in 4 people say that sleep problems impair
their ability to function during the day.
• High School students: Only 15% get the 8.5
hours recommended.
Sleep Deprivation
• Lack of sleep can;
– Slow reaction time
– Impair concentration
– Impair memory
– Impair problem-solving ability
– Make it more difficult to retain newly acquired
information
– Impair academic performance
Sleep Deprivation
• Sleep deprivation is among the most common
cause of motor vehicle accidents.
• Loss of REM sleep affects learning ability and
memory.
• Prolonged sleep deprivation can lead to
hypertension, a cardiovascular disease and
potential killer.