Sleep and Sleep HistoriesDouglas Moul, M.D., M.P.H.

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“Consciousness is consciousness of an object.”

-- Jean-Paul Sartre

Death = Sleep ?

To be or not to be, that is the question-- whether it is more noble in the mind to suffer the slings and arrows of outrageous fortune, or to take arms against a sea of troubles, and by opposing, end them --

To die..., to sleep..., perchance to dream…

-- Hamlet

Modes of Sentience

• Wakefulness

• Slow Wave Sleep

• Rapid Eye-Movement Sleep

Modes of Insentience

• ComaComa

• DeathDeath

Hallucinations and Dreams

• Both often occur in the absence of a consensually validated stimulus.

• Both are experienced perceptually.

• Both can dominate awareness

• Both can be pleasant or unpleasant

• Both can at times cause overt behavior

Hallucinations vs. Dreams

• Usually during wakefulness

• Auditory > Visual• Not volitionally guided• Interferes with the stream

of thought• Usually not built from

ordinary daily events

• Usually during REM sleep• Visual > Auditory• “Lucid” Dreams can be

thematically guided• When experienced, is the

stream of thought• Often contain “day

residues.”

Myths about Sleep and Dreams

• If a person doesn’t get sleep, he or she will become psychotic.

• Everyone must get 7.5 hours of sleep.

• Psychiatrists are taught how to interpret dreams properly.

• Nightmares and hypnopompic/hypnogogic hallucinations are abnormal.

• Sleep apneas are always abnormal.

A Good Brain Anatomy Site:

http://pegasus.cc.ucf.edu/~Brainmd1/brain.html#table

Stage I Sleep: Going to Sleep

• Usually requires state of lowered autonomic arousal

• Transition from alpha to theta waves on EEG

• Is a light sleep, easily responsive to sounds

• Typically lasts from 1 to 7 minutes

• Hypnic Myoclonus may occur

Stage II Sleep: The Thalamus’ Reticular Nucleus’ Sleep Spindles

• Sleep Spindles and K complexes

• Bodily movements continue

• Lasts usually 10-25 minutes during first cycle

• Constitutes 45-55% of sleep

• Probably initiates 0.5o F temperature reduction through the Hypothalamus

Stages III-IV: Deep Sleep

• High voltage Delta waves now predominate in EEG

• High stimulus thresholds normally for arousal.

• Psychologically probably the stage that tells a person he has slept.

• Skeletal muscles still active!

REM Sleep• Usually is an arousal from Delta sleep

• Desynchrony in the EEG

• PGO waves from Pons to Thalamus to Cortex

• Theta waves in Septum and Hippocampus (related to memory/dream function?)

• Pontine reticular formation activation with skeletal muscle atonia and poikilothermia

• Lowered cardiac and pulmonary rhythms

• Periodic penile and clitoral tumescence

Wakefulness• Greater tendency to arouse from REM (REM

propensity is circadian; SWS propensity is about length-of-wakefulness)

• Septal and Hippocampal Theta waves occur during wakefulness !

• With apneas, brief awake spells can be forgotten

• Sleepiness and Fatigue can be different symptoms.

Breathing During Sleep• Sleep onset resets chemical sensitivity to PO2 and

PCO2

• In moving to new setpoints, apneas may occur, and are fairly normal

• PCO2 usually the critical setpoint for breathing during sleep

• Decreased pharyngeal tone: snoring and obstructive sleep apnea

• Greater irregularity during REM sleep

Prominent Nocturnal Hormone Patterns

• Cortisol starts out decreasing, reaches a daily minimum, then rises to a daily maximum about dawn.

• 80% of Growth Hormone can occur in the first Delta sleep period.

• Melatonin is entrained to the circadian and seasonal rhythms if not directly suppressed by bright light.

Three Physiological Factors regarding Sleep Propensity

• Previous Sleep Debt

• State of Autonomic Arousal

• Circadian Time

Effects of Sleep Deprivation

• Decreased sleep latency• Risk of microsleeps• Lowered intellectual

performance and creativity• Irritability• Decreased vigilance• Danger of switches to Mania in

Bipolar patients

• Temporarily decreased depressive mood in some depressed patients

GoodGoodNot so GoodNot so Good

Factual Pearls concerning Sleep• There is a 90-minute NonREM-REM Cycle of

sleep stages across the night

• Circadian maturity only begins to appear by 6 weeks post-partum, and may take months; Infants have a lot of REM sleep.

• Women as a group have better sleep architecture, but lower sleep quality than men.

• The elderly may not have any Delta sleep and generally have lighter sleep

Effects of Alcohol• Alcohol (affects GABA & other receptors )

induces sleep, decreases pharyngeal muscle tone encouraging obstructive sleep apneas, and initially depresses REM; later in the night REM rebounds, with possible nightmares and/or awakening.

• Sober alcoholics can expect to have poorer sleep architecture and sleep satisfaction for over a year after they have stopped drinking.

Effects of Other Layman Drugs

• Caffeine antagonizes Adenosine, a neuromodulator that decreases secretion of autonomically active chemicals (DA, NE,etc.)

• H1 Antihistamines antagonize Histamine, an activating neurochemical during wakefulness

• Nicotine is a cholinergic stimulant.

• Drugs with Anticholinergic properties may help with sleep, but impair daytime memory

Effects of Common Medications

• Benzodiazepines (e.g. Valium) (affect GABA) tend to suppress SWS

• Antidepressants and MAOIs tend to suppress REM Sleep

• Stimulants usually act on Dopamine or Norepinephrine and suppress all stages.

• Many medications hit multiple receptors, and their effects on sleep can be dose-dependent and somewhat unpredictable.