COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
PHYSIOLOGY AND PSYCHOLOGY OF SLEEP:
PREPARATION BY:
TWANA A RAHIM; FIBMSPSYCH, MBCHB
A. PROFESSOR OF PSYCHIATRY
DEPARTMENT OF PSYCHIATRY, COLLEGE OF MEDICINE, HMU.
LECTURE OUTLINE:
- AIMS OF THE LECTURE.
- WHAT IS BIOLOGICAL CLOCK?
- WHAT IS CIRCADIAN RHYTHM?
- SLEEP.
- DREAM.
- HYPNOSIS.
AIMS OF THE LECTURE:
This TWO hours lecture has been involved at the fourth year psychology syllabus because SLEEPING is
considered as a one of the most cardinal physiological function of the brain. Sleep helps human being,
throughout the history of evolution in protecting against dangers, preservation of energy, as well as a crucial
period for the relaxation of both the body and mind.
At the end of the lecture, candidates are expected to understand the meaning of the terms, brain mechanisms
behind the processes of sleeping and wakefulness, stages of sleep, and the concept of dreaming.
WHAT IS BIOLOGICAL CLOCK?
A tendency of an organism to have regular periodic changes or rhythms in physiological and behavioral
functions at approximately the same time each day, each month, or once a year, etc…
E.g. Circadian rhythm, menstrual cycle, seasonal patterns of activities.
Biological clock determined by chemical agents (neurotransmitters, hormones, etc….), process of learning
(evolution) and environmental stimuli.
WHAT IS CIRCADIAN RHYTHM?
Circadian Rhythm: (circa dies = about a day) (Latin word)
Is a biological activity that follows cycles which repeat itself over around 24 hours.
e.g. Normal sleep-wake cycle
Volume of urine excreted /24 hours
Body temperature changes / 24 hours
Food and Drink intakes / 24 hours
EEG activities changes /24 hours, etc…
SLEEP: (Somnus) (Hypnos-God of Sleep)
Is an altered state of consciousness in which the brain for a time gives up some of its functions.
Why we sleep? Functions of sleep:
1- Sleep is a time of rest to both the body and the mind.
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PHYSIOLOGY AND PSYCHOLOGY OF SLEEP
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
2- Sleep comes about in evolution to preserve energy and protect individual during the 24 hours.
3- Bulk of growth hormone secretions occur during sleep, sleep deprivation leads to growth impairment.
4- During sleep, the mind consolidates newly learned data (consolidation of memory).
Stages of Sleep:

Non REM sleep
Stage 1
Stage 2
Stage 3 (Slow Wave Sleep)(Deep Sleep)(Orthodox)( Non Dream)(Synchronized)(Passive)
Stage 4(Slow Wave Sleep)(Deep Sleep)(Orthodox)( Non Dream)(Synchronized)(Passive)
 REM sleep (Paradox)(Dream)(De-Synchronized)(Active)
Note: REM = Rapid Eye Movement
Sleep
% of total
normal adult
sleep
Non REM Sleep
Stage1
Stage 2
Stage 3(Slow Wave Sleep)(Deep Sleep)
Stage 4(Slow Wave Sleep)(Deep Sleep)
5%
45%
12%
13%
REM Sleep
25%
EEG Pattern
Theta Waves,4-7c/s, (small, regular, slow)
12-14c/s, (Sleep Spindle and K-Complex)
Delta Waves, up to 4c/s,(large, slow,
irregular)
Delta Waves, up to 4c/s,(large, slow,
irregular)
Beta Waves,14-25c/s, (small, rapid,
irregular)
Comparison between Non REM sleep and REM sleep:
Non-REM
REM
Eye movement
Absent
Very rapid 10-20/s
HR, RR, BP
Decreased
Increased
Muscles
Increased relaxation
Almost completely paralyzed
(except heart, diaphragm,
smooth muscles and eyes
muscles)
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PHYSIOLOGY AND PSYCHOLOGY OF SLEEP
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
Metabolic rate of brain
Decreased to 25-30% of
wakefulness
Comparable with wakefulness
Dreams
Only 25% of times record
dreams and are not vivid, more
like normal thinking and more
related to what is happened in
the awakened day
No
Almost always recorded if
awakened at it, and are vivid,
surrealist
Night terror, enuresis,
walking
Yes
No
Penile/Clitoral erection
No
Yes
Stages and EEG recordsI-
Stage 1: 5% of total sleep,
theta waves (4-7 htz).
Stage 2: 45% of total sleep,
spindles and K-complex ( 12-14
htz).
Stage 3 and 4 (slow wave
sleep) 25% of total sleep, delta
waves, (0.5- 4 htz).
Is characterized by an idle
brain in a very relaxed body.
REM Sleep: 25% of total
sleep, Beta waves (14- 25
htz)
Night mares
II-
III-
Summary
Yes
Is characterized by a wide
awake brain in a paralyzed
body.
Sleep Pattern and Age:
-
Infants: about half of the sleep time is REM sleep.
5 years old: about 25% of the sleep time is REM sleep.
Old age: less than 18% of the sleep time is REM sleep.
Also both stage III and stage IV decrease with aging.
Sleep Time:
-
Normal adult sleeps about 6-9 hours /24 hours.
Infant spend more than 15 hours in sleep.
Sleep time decreased with age.
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PHYSIOLOGY AND PSYCHOLOGY OF SLEEP
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
Sleep Cycle:
-
It takes about 90 minutes ( S I, S II, S III, S IV, S III, S II, REM).
4-5 cycles occur per regular and normal night sleep.
REM sleep occurs 4-5 times per an 8 hours night sleep
Non REM sleep tends to disappear in the second half of sleep and REM predominates near morning.
Brain Mechanisms Controlling Sleep:
-
1-
Sleep and wakefulness controlled by a complex network including Reticular Formation, Cortex,
Hypothalamus, Pineal Gland, and several Neurotransmitters and Hormones:
Circadian Rhythm is controlled by suprachiasmatic nucleus in Hypothalamus.
Pineal Gland secretes melatonin hormone. Melatonin secretion increased at night and decreased at day.
However, Melatonin is neither essential for sleepiness nor for circadian rhythm!.
Control of slow wave sleep (SWS) is by raphe nuclei located in Medulla and Pons which secret Serotonin all
over, whereby cortical activities decreased and it prevents stimuli to reach cortex from spinal cord.
Shifting of SWS to REM sleep done by 2 sets of neurons in Pons: one increase the brain activity through Nor
adrenalin, and the second calm down the motor neurons (body paralysis) through activation of
parasympathetic nervous system (Acetyl Choline)( the same reason behind erection of genitalia that occurs
during REM sleep). However, eye movement, heart and diaphragm muscles keep working through
Noradrenalin.
Wakefulness: maintained by:
Acetylcholine: awaken the individual
Nor adrenalin and Adrenalin
Dopamine
Glutamate: is important in wakefulness and alertness, its reduction result in impaired concentration and
attention.
Histamine: is important for wakefulness and alertness; if reduced it result in sedation.
Glucocorticoids
2-
Non REM sleep: maintained by:
GABA: is an inhibitory substance, GABA agents , induce sleep and increase sleep duration.
Serotonin
Adenosine: blockade by xanthenes (Caffeine) promote wakefulness.
Cholecystokinin (which produces satiety) and bombesin (postprandial sleep)(heavy meal sleep): after having
meal, these 2 substances secreted from the gut. They act either directly on the periventricular regions of the
brain, or indirectly through vagal afferents to the brain stem causing drowsiness.
- Muramyl Peptide, produced by bacteria in the gut and is also inducing sleep, either by its own or through
Interleukin 1.
- Endogenous Opiates: initiate and maintain sleep.
3- REM sleep: maintained by:
- Serotonin, nor adrenalin, Dopamine, and Acetyl choline are involved in dreaming and maintaining of REM
sleep.
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PHYSIOLOGY AND PSYCHOLOGY OF SLEEP
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
DREAMING:
Dream is an altered state of consciousness in which remembered images and fantasies are
temporarily confused with external reality. Till now, nobody knows why we dream at all, but it could be
viewed as a side effect of the highly activated brain during REM sleep, or as it has been proposed by Freud,
as the Royal Road To Unconsciousness!
Does everybody dream? Yes, all of us dream, if somebody says {I never dreamed}, it means that {I can’t
recall my dreams}.
How long does dream lasts? Dream time is equal to REM sleep time, and incidents in dreams commonly
last about as long as they would in real life.
Can people control the content of their own dreams? Is possible sometimes by suggestion, or in posthypnotic suggestion.
How many types of dream we have? Two types:
1- True Dream (Vivid Dream): Is the dream that experienced as if it was a real life event rather than something
merely imagined or thought about. It occurs in REM sleep. Dreams fleet out from memory quickly and it
recalled best if the person awakened during REM sleep or while the person is dreaming.
2- Sleep thought: Is some sort of mental activities just before awakening from SWS sleep which lacks the
vivid sensory and motor hallucinations of true dreams, and is more similar to day time thinking and is
concerning with some problems immediately before sleep.
HYPNOSIS: (Hypnos= God of Sleep) (Greek Mythology)
1234-
Is a state of sleep induced by suggestion with or without medications for:
Relaxation as a sort of Psychotherapy.
As analysis of the unconscious conflicts and stresses by Freudian Psychoanalysts.
Sleep studies purposes.
In the past for the prediction of future which revealed unreliability later on.
Hypnosis done first by Anton Mesmer (1734-1815) in Viennese, later on by many physicians including James
Braid, Charcot, Jean Martin, Sigmund Freud and many others.
Nowadays, Hypnosis is regarded as a matter of historical interest.
END
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PHYSIOLOGY AND PSYCHOLOGY OF SLEEP