Ch. 5 Sleep and Consciousness

What is Consciousness?

Awareness of oneself and the environment, varying in levels from alertness (consciousness) to sleep.

What factors can influence Consciousness?

External factors (ex. drugs) and internal factors (ex. mental effort).

What is Alertness?

A state of being awake, aware, focused, and able to process and store information.

What is Daydreaming?

A relaxed state with reduced focus, sometimes involving light self

What is Drowsiness?

A transitional state before sleep or after waking, also seen in deep meditation.

What is Sleep?

A state of reduced awareness of self and environment.

What is an EEG (electroencephalogram)?

A tool used to measure brainwave activity.

What are Brain waves (neural rhythms)?

Patterns of neuronal firing that produce measurable brainwave oscillations.

What are the four main types of brainwaves?

Alpha, beta, theta, and delta waves.

What are Beta Waves?

High-frequency (12–30 Hz) waves associated with alertness and concentration

What are Alpha Waves?

Moderate-frequency (8–13 Hz) waves associated with relaxation and daydreaming

What are Theta Waves?

Lower-frequency (4–7 Hz) waves associated with drowsiness and light sleep

What are Delta Waves?

Very low-frequency (0.5–3 Hz) waves associated with deep sleep.

How do brainwaves change during sleep?

Different stages of sleep are characterized by different brainwave patterns.

Are you aware of transitions between sleep stages?

No, transitions are typically not consciously perceived.

Which brainwaves are seen during alertness?

Beta waves.

Which brainwaves are seen during relaxation?

Alpha waves.

Which brainwaves are seen during early sleep?

Theta waves.

Which brainwaves dominate deep sleep?

Delta waves.

What happens with prolonged beta wave activity?

Increased stress and anxiety.

What tool measures brain activity during sleep?

EEG (electroencephalogram)

What are the main Sleep Stages?

N1, N2, N3 (non-REM) and REM sleep

How long is one full sleep cycle of the 4 stages of sleep?

About 90 minutes.

How many sleep cycles occur per night?

Typically 4–5 cycles.

What is the order of sleep stages in a cycle?

N1 → N2 → N3 → N2 → REM.

What are the first three stages of sleep categorized in?

Non-rapid eye movement sleep

What is the shortened version of Non-rapid eye movement sleep?

non-REM

What is N1 sleep?

The lightest stage of sleep, dominated by Theta waves.

What may you experience during N1 sleep?

Hypnagogic Hallucinations, Hypnic Jerks, or “Tetris Effect”

What are Hypnagogic Hallucinations?

Sensory experiences (seeing/hearing things) as you fall asleep.

What is the “Tetris Effect”?

Replaying recent experiences visually during early sleep.

What is an example of the “Tetris Effect”?

Ex. Been on a boat all day, you might still feel like you are on water even when on dry land

What are Hypnic Jerks?

Sudden muscle twitches or feeling of falling during N1 sleep.

What is N2 sleep?

A deeper stage of sleep (harder to wake) with theta waves, sleep spindles, and K-complexes.

What are Sleep Spindles?

Bursts of rapid brain activity that help maintain sleep.

What is the function of Sleep Spindles?

To inhibit external stimuli and help you stay asleep.

What are K-complexes?

Large brain waves that suppress cortical arousal and aid memory consolidation.

What is the function of K-complexes?

To keep you asleep and assist in memory consolidation.

How does K-complexes aid memory consolidation?

Some memories are transferred to long term memory during sleep, particularly declarative/explicit memories

What is N3 sleep?

Deep sleep (slow-wave sleep) dominated by delta waves.

What happens during N3 sleep?

Sleepwalking, sleep talking, and declarative memory consolidation.

Which stage is hardest to wake someone from?

N3 sleep.

What is the last stage of sleep categorized in?

REM sleep

What is REM sleep?

A stage with rapid eye movement, vivid dreaming, muscle paralysis, and memory consolidation (Formation of episodic memories.)

Why are muscles paralyzed during REM sleep?

To prevent acting out dreams.

Why is REM sleep called Paradoxical Sleep?

Because brain activity resembles wakefulness while the body is paralyzed.

When does most dreaming occur?

During REM sleep.

What type of brainwaves are seen in REM sleep?

Mixed waves (alpha, beta, and dyssynchronous waves) similar to beta (high activity).

What happens if you wake up during REM sleep?

You are more likely to remember your dreams.

When is REM sleep most abundant?

Closer to waking.

When is N3 sleep most abundant?

Early in your sleep

What type of memory is consolidated in N3 sleep?

Declarative (explicit) memory.

What type of memory is consolidated in REM sleep?

Procedural and episodic memory.

What is the order within a sleep cycle goes from?

N1 -> N2 -> N3 -> N2 -> REM -> N1.

How long does each stage of sleep last?

It lasts depending on how long you’ve been asleep and your age (babies spend more time in REM sleep)

What are Circadian Rhythms?

Biological cycles that follow a 24-hour period.

What hormone regulates Circadian Rhythms?

Melatonin.

Where is Melatonin produced?

In the Pineal Gland.

What factors influence Circadian Rhythms?

Light exposure (natural and artificial).

How do Circadian Rhythms change with age?

Younger people stay up later; older people sleep earlier.

Why might Circadian Rhythms prevent sleeping in?

They regulate your natural wake/sleep timing.

Which sleep stage has theta waves?

N1 and N2.

Which sleep stage has sleep spindles and K-complexes?

N2

Which sleep stage has delta waves?

N3.

Which stage is associated with dreaming?

REM sleep.

Which stage is associated with muscle paralysis?

REM sleep.

Which stage is associated with sleepwalking?

N3.

Which stage consolidates declarative memory?

N3.

Which stage consolidates procedural memory?

REM.

What controls circadian rhythms?

Melatonin and light exposure.

During which stage of sleep do most dreams occur?

REM sleep.

How can you tell someone is in REM sleep?

Their eyes move rapidly and brain activity resembles wakefulness.

Are REM dreams memorable?

Yes, REM dreams are the most vivid and memorable.

Are dreams in NREM sleep memorable?

No, they are typically less vivid and not easily remembered.

What happens to the prefrontal cortex during REM sleep?

Its activity decreases.

Why do dreams often seem illogical?

Because the prefrontal cortex (logic center) is less active.

What theories explain why dreams occur?

Sigmund Freud, Evolutionary biology (Threat simulation, Problem solving, No purpose), Maintain brain flexibility, consolidate information, and Preserve & developing neural pathways

What is Sigmund Freud’s theory of dreams?

Dreams represent unconscious thoughts and desires.

Does Sigmund Freud’s theory of dreams have strong scientific support?

No, it has limited scientific support.

What is the Evolutionary biology theory of dreaming?

Dreams simulate threats to prepare us for real

How might dreams help with learning and creativity?

By maintaining brain flexibility.

How are dreams related to memory?

They may help consolidate information into long

What evidence supports the role of sleep in memory?

People who sleep after learning retain more information.

Do scientists fully understand the role of REM in memory?

No, its exact role is still unclear.

Why do infants spend more time in REM sleep?

To help develop and preserve neural pathways.

What is the memory consolidation theory of sleep?

Memories are strengthened and stored during sleep, especially deep sleep.

Which brain region is less active during REM sleep?

Prefrontal cortex.

Why are REM dreams bizarre?

Reduced logical processing in the brain.

Which sleep stage is most associated with vivid dreams?

REM sleep.

What is one evolutionary function of dreams?

Simulating threats.

What happens if you wake up during REM sleep?

You are more likely to remember the dream.

What does Sigmund Freud’s theory of dreams say about dreams?

Dreams represent unconscious thoughts, feelings, and urges.

What is the iceberg analogy in Freud’s dream theory?

Most mental content is hidden (unconscious), with only a small portion being conscious.

According to Freud’s dream theory, what would the manifest content in dreams be?

The literal storyline or events of the dream.

According to Freud’s dream theory, what would the latent content in dreams be ?

The hidden psychological meaning of the dream.

What is an example of manifest content in Freud’s dream theory?

Being chased by a monster in a dream.

What is an example of latent content in Freud’s dream theory?

Being chased may represent stress from being pushed out of a job.

What is Freud’s idea about Dream Interpretation?

Dreams can be analyzed to uncover unconscious conflicts.

What is the Activation-Synthesis Hypothesis?

A theory that dreams result from the brain trying to make sense of random neural activity.

What part of the brain is responsible for activation in Activation-Synthesis Hypothesis?

The brainstem