Sleep and Dreams

Question 1

What four characteristics help to define sleep?

Answer 1

The four characteristics that help to define sleep are:

1. Diminished motor ability
2. Reduced responses to external stimuli
3. Generalized posture
4. Readily reversible state

These characteristics distinguish sleep from both coma and hibernation.

Question 2

Define:

an EEG

Answer 2

An EEG (electroencephalogram) is a test that measures and records the electrical activity of the brain.

During an EEG electrodes are attached to the scalp and a computer records lines that correspond to the brain’s electrical waves.

EEGs are commonly used in sleep studies and for many other brain-related diagnostic tests.

Question 3

List the four types of EEG waves in order of decreasing frequency.

Answer 3

In order of decreasing frequency, the four types of EEG waves are:

1. Beta waves (13-60 Hz)
2. Alpha waves (8-12 Hz)
3. Theta waves (3-8 Hz)
4. Delta waves (0.5-3 Hz)

At the same time, as frequency of the waves decreases, amplitude increases.

Question 4

Define:

Non-REM sleep

Answer 4

Non-REM sleep first occurs right after falling asleep and is characterized by a progressive decrease in brain activity; the person gradually falls into a deeper sleep.

Non-REM is comprised of four stages of varying brain waves; all of which are considered slow, high altitude oscillations.

Question 5

Which component of the body’s nervous system is activated during non-REM sleep?

Answer 5

During non-REM sleep, the parasympathetic nervous system is most predominant.

During this time, general metabolism slows, leading to a decrease in body temperature, heart rate, respiratory rate, energy consumption, and kidney function.

Question 6

Describe:

stage 1 of non-REM sleep

Answer 6

Stage 1 of non-REM sleep is the very start of the sleep cycle, when the sleeper first lies down, closes his eyes, and begins to relax.

Stage 1 begins with rapid beta waves, moves towards slower alpha waves, and ends with the emergence of theta waves.

Waking a person from sleep is easiest during stage 1, despite a markedly diminished reaction to stimuli.

Question 7

How long does stage 1 of non-REM sleep typically last?

Answer 7

Stage 1 lasts between 3 and 12 minutes.

Stage 1 accounts for only 5% of a young adult’s total sleep cycle.

Question 8

Describe:

stage 2 of non-REM sleep

Answer 8

Stage 2 of non-REM sleep is the stage of light sleep marked by an even greater decline in external stimuli response.

The theta waves associated with stage 2 continue to decrease in speed and are often interrupted with high frequency waves, called sleep spindles, and high altitude waves, called K-complexes.

Question 9

How long does stage 2 of non-REM sleep typically last?

Answer 9

Stage 2 lasts between 10 and 20 minutes.

Stage 2 accounts for more than 50% of a young adult’s total sleep cycle.

Question 10

Describe:

stage 3 of non-REM sleep

Answer 10

Stage 3 of non-REM sleep marks the passage into deep sleep in which the sleeper shows very little response to external stimuli.

During stage 3, the slow delta waves appear on EEG, while the presence of sleep spindles and K-complexes diminish.

Question 11

How long does stage 3 of non-REM sleep typically last?

Answer 11

Stage 3 lasts approximately 10 minutes in the first sleep cycle, but decreases in subsequent cycles.

Stage 3 accounts for approximately 7% of a young adult’s total sleep cycle.

Question 12

Describe:

stage 4 of non-REM sleep

Answer 12

Stage 4 of non-REM sleep is the deepest stage of sleep, in which neuronal activity is at its highest. Stage 4 experiences the highest respiratory rate, breathing rate, heart rate, and blood pressure.

Delta waves dominate the EEG in this stage of sleep.

Question 13

How long does stage 4 of non-REM sleep typically last?

Answer 13

Stage 4 lasts approximately 35-40 minutes during the first sleep cycle.

Stage 4 accounts for 15-20% of a young adult’s total sleep cycle.

Question 14

Define:

REM sleep

Answer 14

REM is characterized by high energy brainwaves, similar to those found in the wake cycle, and rapid eye movement, from which REM sleep gets its name.

The first cycle of REM sleep occurs after the first complete cycle of non-REM sleep.

Question 15

What are five characteristics of REM sleep?

Answer 15

Five characteristics of REM sleep are:

1. Low amplitude, high frequency wave lengths
2. Vivid, internally produced sensations
3. Motor activity of extremities is non-existent
4. Frequent and rapid movement of the eyes (REM)
5. Repetitive and illogical thoughts

Question 16

How long does REM sleep typically last?

Answer 16

REM sleep lasts about 10-15 minutes.

REM sleep comprises approximately 20-25% of an adult’s sleep cycle.

Question 17

On average, how many hours does an adult sleep per night?

Answer 17

Adults get an average of 7-8 hours of sleep per night.

The amount of sleep people receive is influenced by genetic make-up, lifestyle, and age.

Typically, as humans age, sleep becomes more frequent and fragmented.

Question 18

Describe:

the basic order of stages of the sleep cycle

Answer 18

The sleep cycle begins with stage 1 of non-REM and progresses through stages 2-4 before REM sleep is reached. After REM, sleep progresses back through non-REM beginning with stage 4 and ending with stage 1. The cycle continues to repeat throughout the night.

Question 19

How long does each sleep cycle last?

Answer 19

Depending on the individual, each sleep cycle lasts anywhere from 1.5 to 2 hours.

Question 20

How many complete sleep cycles are typical of a full night’s sleep?

Answer 20

In a full night’s sleep, the sleep cycle is typically completed 4 to 6 times.

Question 21

What stage of sleep consumes the largest proportion of the sleep cycle?

Answer 21

Stage 2 of non-REM consumes the largest proportion of the sleep cycle at 50-60%.

Question 22

During which stage of the sleep cycle does dreaming occur?

Answer 22

Dreaming can occur during both REM and non-REM sleep.

Non-REM dreams are often short, with concrete and logical structure. On the other hand, REM sleep dreams are vivid, emotional, and often illogical.

Question 23

Define:

the psychoanalytic theory, as it relates to dreams

Answer 23

The psychoanalytic theory of dreams holds that dreams are a window into the unconscious, whereby repressed desires, feelings, and emotions are revealed.

The psychologist Sigmund Freud is considered to be the father of the psychoanalytic theory.

Question 24

Define:

the activation-synthesis model, as it relates to dreams

Answer 24

The activation-synthesis model holds that dreams are the result of the sleeping brain’s attempt to assign meaning to and extract coherent images from the random nerve impulses sent through the sleeping brain.

Question 25

Define:

the active unlearning theory, as it relates to dreams

Answer 25

The active unlearning theory holds that dreams are the result of the brain examining the stimuli it has received throughout the day and discarding the information that has no meaning.

The active unlearning theory may explain why dreams are so difficult to remember, as it is information we are supposed to forget anyway.

Question 26

What are some symptoms of sleep deprivation syndrome?

Answer 26

Some symptoms of sleep deprivation syndrome include:

1. Decreased alertness and ability to think and concentrate
2. Slowed reflexes
3. Issues with remembering
4. Muscle fatigue
5. Mood swings
6. Hallucinations

Question 27

Define:

insomnia

Answer 27

Insomnia is the inability to get the quantity or quality of sleep needed to avoid the symptoms of sleep deprivation and to function on a daily basis.

There are two types of insomnia; transitory insomnia and chronic insomnia.

Question 28

Define:

transitory insomnia

Answer 28

Transitory insomnia is a type of insomnia that is short-term, lasting at most a few weeks, and typically results from high levels of stress or caffeine, or even jet lag.

Question 29

Define:

chronic insomnia

Answer 29

Chronic insomnia is a long-lasting form of insomnia that typically lasts for longer than a month and can be caused by a multitude of external or internal issues.

External issues include factors such as excessive heat, cold, or noise.

Internal issues include factors such as chronic pain, coughing, or difficulty breathing, as well as psychological illnesses such as depression.

Question 30

Define:

sleep apnea

Answer 30

Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing rate.

Question 31

Define:

hypersomnia

Answer 31

Hypersomnia is a type of sleep disorder characterized by excessive daytime sleepiness that is not a result of lack of sleep during the night, but rather a malfunction of the neurons responsible for sleeping and waking.

Example: narcolepsy

Question 32

Define:

parasomnia

Answer 32

Parasomnia represents the type of sleep disorder marked by anything abnormal that occurs during sleep.

Examples: nightmares, night terrors, sleepwalking, sleeptalking, and tooth grinding.

Question 33

Define:

a nightmare

Answer 33

A nightmare is a dream that has frightening visual images and negative emotions strong enough to cause the dreamer to awaken feeling scared and anxious.

Nightmares, typical of dreams, can be recalled in the morning.

Question 34

Define:

a night terror

Answer 34

A night terror is an episode in which the sleeper experiences frightening visual images, typically screams and cries, has their eyes open, says incoherrent words, and forms gestures. Upon waking, the sleeper often has elevated blood pressure, heart rate, breathing rate, and profuse sweating.

Night terrors are not recalled in the morning and the sleeper normally wakes up feeling very confused.

While night terrors are common in young children, they tend to disappear by adolescence.

Question 35

What are the differences between night terrors and nightmares?

Answer 35

The differences between night terrors and nightmares are:

1. Nightmares are often recalled in the morning, while sufferers of night terrors have no recollection of the event.
2. Nightmares occur more during REM sleep, while night terrors occur during stage 3 and 4 of non-REM.

Question 36

What are the five major neurotransmitters involved with inducing a state of wakefulness?

Answer 36

The five major neurotransmitters involved with inducing a state of wakefulness are:

1. Serotonin
2. Histamine
3. Norepinephrine
4. Acetylcholine
5. Glutamate