1. Waking and Sleeping Rhythms

2. Our awareness of ourselves and our surroundings.
When we are awake we are?
In a state of Consciousness
Our awareness of ourselves and our surroundings.

3. Biological Rhythms– periodic fluctuations of living things
Annual Cycles: seasonal variations (bears hibernation, seasonal affective disorder)
28 day cycles: menstrual cycle.
24 hour cycle: our circadian rhythm
90 minute cycle: sleep cycles.

4. Circadian Rhythm Our 24 hour biological clock.
Our body temperature and awareness changes throughout the day.
It is best to take a test or study during your circadian peaks. (can be different for everyone)

6. Sleep Stages
There are 4 identified stages of sleep (your book says 5 b/c stage 3 and 4 have been combined).
It takes about minutes to pass through all 4 stages.
The brain’s waves will change according to the sleep stage you are in.

7. Stage One
This is experienced as falling to sleep and is a transition stage between wake and sleep.
Unaware when we enter this stage
It usually lasts between 1 and 5 minutes and occupies approximately 2-5 % of a normal night of sleep.
Unless you wake up, you will only go through Stage One once during the night.
eyes begin to roll slightly.
consists mostly of theta waves (high amplitude, low frequency (slow))
brief periods of alpha waves, similar to those present while awake
Hallucinations can occur and feeling of falling /floating .

9. Stage Two This follows Stage 1 sleep and is the "baseline" of sleep.
This stage is part of the 90 minute cycle and occupies approximately 45-60% of sleep.
Theta waves with sleep spindles

11. Stage Three Used to be Stages 3 and 4, now just 3
Stage three is "Delta" sleep or "slow wave" sleep and may last minutes.
It is called "slow wave" sleep because brain activity slows down dramatically from the "theta" rhythm of Stage 2 to a much slower rhythm called "delta" and the height or amplitude of the waves increases dramatically.

12. Stage Three/Four
Contrary to popular belief, it is this stage that is the "deepest" stage of sleep (not REM)
In children, delta sleep can occupy up to 40% of all sleep time and this is what makes children unable to be awakened or "dead asleep" during most of the night.

14. Last stage: REM SLEEP REM: Rapid Eye Movement
This is a very active stage of sleep (mentally)
Composes % of a normal nights sleep.
Paradoxical sleep - Breathing, heart rate and brain wave activity quicken, but body paralyzed.
Vivid Dreams can occur.
From REM, you go back to Stage 2

18. Review Questions How long is one sleep cycle?
What sleep cycle is mostly delta waves?
What is the deepest stage of sleep? What is the lightest stage of sleep?
What stage of sleep consists of alpha and theta waves?
What is the 24 hour internal clock called?
During which stage do the most dreams occur?
What happens to stage three sleep as the night goes on?

19. How much sleep do we need?
We all need different amounts of sleep depending on our age and genetics.(6-9 hours is generally recommended – more for teenagers and kids)
But we all sleep- about 25 years on average.
How do you feel when you don’t get enough sleep?

20. What controls the sleep/wake cycle?
The Brain!
Serotonin and Dopamine – stops mvmnt during REM; can also aid in arousal in reticular formation
Hypothalamus
Suprachiasmatic nucleus – internal clock; sensitive to changes in light; tells pineal gland to secrete melatonin. (not melanin)
As melatonin accumulates, sleepiness increases
As light hits the eyes, the SCN tells the pineal gland to stop secreting melatonin

21. Why do we need sleep? (four theories)
Ecological Niche

22. 2. Sleep helps us recuperate and restores the breakdown of our body.

23. 3. Helps to process memories

24. 4. Plays a role in the growth process
During deep sleep, pituitary releases growth hormone
May explain why adults need less sleep than kids/adolescents

25. Sleep Disorders

26. Insomnia Recurring problems in falling or staying asleep.
Not your once in a while (I have a big test tomorrow) having trouble getting to sleep episodes.
10-15% of adults

27. Narcolepsy Characterized by uncontrollable sleep attacks.
Lapses directly into REM sleep (usually during times of stress or joy).

28. Sleep Apnea
A sleep disorder characterized by temporary cessations of breathing during sleep and consequent momentary reawakening.
Occurs more often in those who are overweight

29. Night Terrors
A sleep disorder characterized by high arousal and an appearance of being terrified.
Occur early in the night during stage 3, not REM like other dreams.
Are not often remembered.

30. Sleepwalking (Somnambulism)
Sleepwalking is a sleep disorder effecting an estimated 10 percent of all humans at least once in their lives.
Sleep walking most often occurs during deep non-REM sleep (Stage 3) early in the night.

31. Why do we dream?

32. Freud’s Theory of Dreams
Dreams are a roadway into our unconscious.
Manifest Content (storyline)
Latent Content (underlying meaning)
Book: The Interpretation of Dreams

33. Information-Processing Theory
REM sleep helps us to remember the day’s events.
We tend to dream more when we are more stressed.
New experiences, thoughts, skills, etc. develop new pathways
REM sleep helps us to develop and preserve neural pathways

34. Activation-Synthesis Theory
Our Cerebral Cortex is trying to interpret random electrical activity sent from the pons.
That is why dreams sometimes make no sense.

35. Activation-information model or AIM
Off-shoot of activation-synthesis theory
The brain uses meaningful bits and pieces from the previous couple of days to help explain the random electrical bursts.