1.5 Sleep, Dreams, and Sleep Disorders

consciousness

awareness of oneself and environment; wakefulness, sleep

sleep

natural, periodic loss of consciousness during which a limited perceptual window exists

circadian rhythm

ancient fundamental adaption to the 24hr solar cycle of light and dark; body processes vary predictably throughout the day (stomach acidity, alertness, BP, body temp, hormone levels)

epinephrine

Which NT peaks in late morning then declines until around midnight?

GABA + melatonin

Which NT surges at night to promote sleep then drop in morning?

disruptions to circadian rhythm

blue light, shift work, jet lag

4: 1, 2, 3, REM

How many stages of sleep are there? What are they?

around 90 minutes

How long does each cycle last?

5-6

How many cycles occur each night?

nREM stages (1-3)

essential part of sleep for the body, shortens as night progresses

stage 3

deepest sleep

hypnagogic sensations

hallucinations, muscle jerks, and sensations of falling while transitioning to sleep

REM (rapid eye movement)

essential part of sleep for mind, increase in HR and BR, eyes move rapidly while asleep, vivid dreams/nightmares and visual/auditory experiences occur

REM rebound

when deprived of REM, the brain will make up for it as soon as possible by shortening nREM cycles and lengthening REM early on during sleep

paradoxical sleep

during REM, physiological measures resemble those during consciousness (brain activity, HR, BP)

movement

active motor cortex-signals blocked by brainstem

paralysis

person appears deeply asleep and incapable of moving (muscles essentially paralyzed)

allows us to conserve + restore energy

Why do we sleep?

7-9 hrs/night

How many hours of sleep should adults get?

8-10 hrs/night

How many hours of sleep should teens get?

around 16 hrs/day

How many hours of sleep should infants get?

limbic system

wildly active during dreaming

occipital + temporal lobes

active during dreaming

frontal lobe

minimal activation during dreaming

consolidation theory

sleep helps us restore and rebuild new memories from the day, especially during REM by converting short- to long-term memories

activation synthesis model

our brains are producing random activity throughout the night; dreams could be the cortex’s attempt to make sense of this random activity by telling a story

lucid dreaming

dreams in which the person is aware they are dreaming and have control over the dream’s content

disrupts hunger signals, slow reaction time, greater risk of accidents, fatigue, impaired concentration, depressed immunity, greater risk of high BP + obesity

What are sleep deprivation symptoms?

insomnia

difficulty falling or staying asleep

sleep apnea

repeated interruptions to breathing during sleep

overweight, smoking, being male, narrow airway

What are sleep apnea causes?

loose weight, CPAP machine, surgery

How do you treat sleep apnea?

narcolepsy

uncontrollable “sleep attacks” (go into REM)

genetics

What are narcolepsy causes?

stimulants, therapy

How do you treat narcolepsy?

somnambulism

20% of kids have it, should help keep the person calm + back to bed, adjust meds, get good sleep, hygiene

night terrors

“sleep panic attack” causing overwhelming panic or dread, occurs during REM and rarely remembered, 3-6% of kids have it, therapy, medications, relaxation exercises

REM sleep behavior disorder

acting out dreams while asleep including vocalizations and violent movements, brainstem doesn’t block signals from motor cortex, associated with neurodegenerative disorders (Parkinson’s, dementia), melatonin, avoid alcohol, injury prevention