Post on 16-Dec-2015
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Consciousness is not all or none
We still have some level of awareness during sleep and even while under anesthesia during surgery
Examples
Electroencephalograph (EEG) –a device that monitors electrical activity of the brain over time◦ Records electrodes attached to surface of scalp
This shows the rhythm of activity of brain (brain waves)
Circadian Rhythm – 24 hour biological cycles found in humans and other species◦ Influential in sleep regulation
These rhythms prime us to fall asleep easily at a certain point in day◦ “ideal” time
What happens when we ignore our biological clocks and sleep at an unusual time?◦ Quality suffers◦ Tired, sluggish, irritable for days, lower cognitive
performance
Equates with “jet lag”
This is especially problematic for workers constantly switching and working odd shifts.◦ What some studies show
Researchers have studied methods to get over this feeling of “jet lag”
Options◦ Certain type of drug (melanonin)◦ Carefully timed exposure to bright light◦ Carefully plan rotation schedules at work
Problem with options
Former thoughts about sleep…
Now realize that much physical and mental activity happens during sleep
How did we form this understanding?◦ Sleep Laboratories
Volunteer patients spend night What happens in these labs?
Video clip
Sleep onset is gradual
Once we fall asleep, humans progress through different stages
Stages 1-4- Commonly referred to as non-REM sleep◦ Respiration, heart rate, and body temperature
decrease with each stage◦ Brain waves increase as we progress
This is the fifth and final sleep stage
REM= Rapid eye movements◦ How are these measured?◦ How were they discovered?
REM is the deepest form of sleep◦ Rapid eye movements◦ High frequency brain waves◦ Dreaming
Sleep cycle (Stages 1-5) repeat during night
Cultures mostly similar in terms of sleep experience and activity◦ Differ on other matters
Co-sleeping- children and parents sleeping together◦ More accepted in other cultures
Examples
Napping◦ Some societies close shops and activities during day
to permit naps for an hour or two examples
Research has focused on sleep restriction – partial sleep deprivation
Seems that much of the U.S. are chronic sufferers◦ Effects our attention, reaction time, decision making
Night time workers fall asleep on job Numerous accidents are result of sleep
deprivation◦ Examples
Selective Deprivation ◦ Many lab studies awake participants whenever they
begin to go into REM◦ Selectively deprived of REM
As nights go by, need to awaken more and more◦ REM begins to happen more spontaneously in these
patients now
Following deprivation: Rebound Effect- patients spend extra time in REM
sleep for one to three nights
Insomnia- chronic problems getting adequate sleep◦ 15-17% of adults suffer from severe insomnia
Narcolepsy- marked by sudden, irresistible onsets of sleep during normal waking periods.◦ Awake directly to REM sleep◦ Very rare
Sleep Apnea- frequent, reflexive gasping for air that awakens person and disrupts sleep◦ Person literally stops breathing for 10 seconds
◦ Clips (if time)