Consciousness, Sleep, & Dreams

Today’s Goal Explain the sleep cycle and why sleep is important.

What is Consciousness?• Awareness of ourselves and our environments

• Preconscious – what is not immediately in your awareness, but can easily be brought to your awareness

• Unconscious – info we are unaware of and would be difficult to become aware of (deep, hidden mind)

Dual Processing• We process information at all levels of

consciousness simultaneously= Two-track mind

Biological Rhythms

= Physiological fluctuations Circadian – 24 hour cycle (i.e. sleep-wake) Ultradian – more than 2x daily (stages of

sleep) Infradian – occur once/month or once/season

(hibernation)

Sleep DebtEffects of Sleep Debt

• Lower hormone levels– Less growth hormone

• More accidents• Hypertension & stress• Poor concentration• Irritability• Suppressed immune

system• Weight gain• Premature aging

Can I make up for sleep debt?

• Takes awhile to make up for sleep debt (not just one big sleep)

• Genetics influence how much sleep we need

So Why Do We Sleep?

• Melatonin makes us feel sleepy• Sleep protects us from harm (ecological niche)• Sleep restores the body–Muscles & tissues– Neurological repair– Growth & cognitive

development

How do we study sleep?• Electroencephalogram (EEG) detects brain wave

patterns

• Electrooculogram (EOG) detects eye movements during dreams

• Electromyogram (EMG) detects muscle tension

EEG

EMG

EOG

Awake REM Deep NREM Sleep

Two Main Types of Sleep

• 90 min. cycle• NREM (non-rapid-eye-movement)– Stages 1-4– 75% of sleep– Restores the body

• REM (rapid-eye-movement)– 25% of sleep– Restores brain– Vivid dreams– Body immobile

Stages of Wake/Sleep • Awake & alert – Beta

waves– Faster, irregular waves

• Awake but relaxed – Alpha waves– Lower frequency,

higher amplitude, more regular

NREM Stage 1• Theta waves• Transition from

wakefulness to sleep

• Frequency slows, amplitude increases

• Hypnic jerks (body shutting down)

NREM Stage 2• Theta waves• Sleep spindles – brief bursts in wave frequency• K Complexes – brief bursts in wave amplitude

Stages 3 & 4: Slow-wave Sleep

• Delta waves• Blood pressure drops• Slowed breathing

REM Sleep

• Paradoxical sleep• Brain is active but

body is immobile• Vivid dreams• Cortisol (stress

hormone) drops• Helps immune

system

• Stage 2 & REM get longer as sleep cycle repeats

Insomnia• Difficulty falling asleep & staying asleep • Oral medications, alcohol worsen the problem

Narcolepsy• Sudden sleep attack when nervous

system is aroused • Fall into immediate REM sleep• Rare (1 in 2000)

Sleep Apnea• Repeated sleep interruptions due to blockage

of air passage (inability to breathe) • Usually do not know this is happening, but

may get full night’s sleep and still feel exhausted

Somnambulism (Sleepwalking)

• Not dangerous to awaken sleepwalker, but difficult (they are in stage 4 of sleep)

Night Terrors

• High arousal and fear response during stage 4 sleep (in children)

• Child rarely has memory of episode• Do not occur in REM (different from

nightmares)

Theories of Dreaming• Activation-synthesis

Random neural firing, our brains create meaning

– PhysiologicalBrain stimulation develops &

preserves neural pathways

• Cognitive developmentReflect person’s cognitive dev. & understanding

Theories of Dreaming• Info-processing

Sort out day’s events & experiences, make memories

• Freud’s wish-fulfillmentManifest content storyline of dreamLatent content underlying meaning, reveals the unconscious