UNIT 5- RG 5A

Sleep and Dreams

Goals for today

●Can you…

○Discuss the circadian rhythm, what it is and how it effects us.

○Identify and explain each of the 5 stages of sleep.

■As well as the typical waves of each stage.

○Describe each sleep disorder.

Rhythm of Sleep

Circadian Rhythms occur on a 24-hour cycle and include sleep

and wakefulnessControlled by the hypothalamus,

specifically the suprachiasmatic

nucleus (SCN)

●receives input from the eyes & is

especially sensitive to the light

dark cycles of day and night

● light signals the SCN to tell the

pineal gland to stop release of

melatonin…in darkness SCN no

longer sends messages,

increasing melatonin

levels and sleepiness

Illustration © Cynthia Turner

2003

Under normal circumstances, the pattern undergoes

daily readjustment by our exposure to light and by our

habitual routines

The Basic Sleep Cycle

The first 90-minutes to sleep

Light sleep

Stage 1 – just drifting to sleep, may experience fantastic

images and/or auditory hallucinations

Stage 2 – more relaxed, clearly asleep – sleep spindles

(short bursts of brain activity) occur

Deep sleep (brain activity significantly slowed)

Stage 3 – transitional stage to deeper sleep

Stage 4 – deepest sleep of all, hard to awaken…only

occurs during the first few cycles of the night

Sleep Stages 1-4 --“Quiet Sleep”

REM Sleep – Paradoxical Sleep

After reaching the deepest sleep stage (4) the sleep cycle

starts moving backward towards stage 1. Although still

asleep, the brain engages in low amplitude, fast and

regular beta waves, much like awake-aroused state.

A person in this sleep phase exhibit Rapid Eye Movements (REM)

and reports vivid dreams.

Brain very active, yet major muscles in body relaxed/paralyzed.

90-minute Cycles during Sleep

With each 90-minute cycle, stage 4 sleep decreases and the duration

of REM sleep increases – most people experience 4-6 cycles a night.

How much sleep do we need?

We spend one third of

our life sleeping.

Genetics influence exactly

how much sleep we

need…however most

humans sleep 9-10 hours if

left unhindered.

Adults need a bit less sleep

than teenagers & children

do.

How much sleep do we need?

Our brain keeps track of

the amount of sleep we

get and does not let us

“make up” for lost sleep.

Keeps track for at least

2 weeks…

Sleep Deprivation

1.difficulty focusing

2.diminished productivity

3.greater tendency to make mistakes

4.irritability and fatigue

5.diminished immune system

6.hallucinations (usually after 72

hours)

Sleep deprivation studies have shown us that sleep is a

necessary biological function. If we don’t get enough

sleep, we can experience…

Sleep Deprivation

The National Sleep Foundation found that over ½ of all

American’s are getting less sleep than they need!

Are you sleep deprived?

Naps – Are they normal?

Biologically speaking, we seem to have a major period of

sleep at night and a smaller period of sleep in the

afternoon which begins around 12 hours after the middle

of the main period of sleep.

If Sam slept from 10pm to 8am last

night, 3 am would the middle of this

period…so Sam is now napping at 3pm.

A 45 minute nap improves alertness for

up to 6 hours…naps longer than 45

minutes signal a sleep deficit.

Sleep Theories

1.Sleep Protects: Sleeping in the darkness when

predators loom kept our ancestors out of harms

way.

2.Sleep Recuperates: Sleep helps restore and

repair brain (and body) tissue.

3.Sleep Helps Remembering: Sleep restores and

rebuilds our fading memories.

4.Sleep and Growth: During sleep pituitary gland

releases growth hormone. Older people release

less of this hormone and sleep less.

Sleep Disorders

1.Insomnia: difficulty falling asleep or

staying asleep

2.Narcolepsy: overpowering urge to fall

asleep that may occur while talking or

standing up■Experience sleep attacks that usually last 5 minutes or

less…this can mean lapsing directly into REM sleep for

some people

Sleep Disorders

1.Night terrors: Sudden arousal from sleep and

intense fear accompanied by physiological

reactions (occurs usually during 1st cycle)

■Seems to be related to some fear the child has…but is not the

same as a nightmare (bad dream)…just see images

■ If not awakened, child often not remember in the morning

2.Sleep apnea: Failure to breathe when asleep ■Wake up (100s) of times a night so

begin breathing again

■Treatments include weight loss

and CPAP machine

Sleep Disorders

1.Sleepwalking: blank stare, move about in a

slow/automatic manner and may

try to eat, dress, or go to the

bathroom in the wrong place■occurs in stage 4 sleep

■technical name…somnambulism

2.REM Behavior Disorder (RBD):

muscles not paralyzed in REM, allowing person to

act out their dreams (usually the vivid, violent,

intense dreams)■Seen more often in middle-age/elderly men, sometimes linked with

Parkinson’s disease

Dreams

Usually story-like

unfolding mental

imagery – most

commonly dreams have

some degree of likeness

to daily activities, yet

tend to be more bizarre

and unrealistic

What do we Dream?

What are some common

themes in YOUR

dreams?

Have you ever had a

recurring dream?

Dreams Questionnaire…

●1000 Psychology Today readers

responded…

○95% said they remembered their dreams

○39% said they could control their dreams

○68% said they had a recurring dream

■What do recurring dreams mean?

○28% said they had died in a dream

○45% said they had dreamed about celebrities

Why do we dream?

1.Wish Fulfillment: Sigmund Freud suggested the

dreams provide a safety valve to discharge

unconscious wants & desires.

○The manifest content (remembered story-line) is a

censored version of the dream’s latent content

(underlying meaning of dream)

2.Information Processing: Dreams may help sift,

sort, and fix day’s experiences in our memories.

Why do we dream?

1.Physiological Function:

Dreams provide

sleeping brain with

periodic stimulation to

develop and preserve

neural pathways. Neural

networks of newborn are

fast developing

therefore need more

sleep.

Why do we dream?

1.Activation-Synthesis Theory: Suggests that in

the brain engages in a lot of neural activity that is

random. Dreams make sense of this activity.

■dreams are the

brain’s interpretations

of its own activity

■SO… they mean

NOTHING!!!

Why do we dream?

1.Cognitive Development: Some researchers

argue that we dream as a part of brain

maturation and cognitive development.

All dream researchers believe we need REM sleep.

When deprived of REM sleep, and then allowed to

sleep, we show increased REM sleep called REM

Rebound.

Dream Theories

Summary

Dream interpretation???