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

?“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.