SLEEP

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• SLEEP
• Circadian
• Humans spend 1/3
• of life sleeping
• (well over 175,000 hrs)
• typically 8 hours/dayso - 3/day extra 21
  hrs/week ? 10,952 hrs/decade!!!

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• SLEEP
• Amount of sleep changes with age younger ages
  sleep more

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Why DO WE SLEEP?
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Do we need sleep? Repair Rest 1965 Randy
Gardner Science fair projectbreak world record
of No sleep (260 hrs) ? 264 hr 12 min 11
days!!! mind over matter First night 15
hrs Next night 9 hrs too bad randy, Mrs.
Maureen Weston (1977) 18 days!!!! Rocking
chair marathon
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Sleep deprivation (3 to 4 hrs) Humans 1.
Increase in sleepiness 2. Mood test 3. Perform
poorly on test of vigilance (ex tones) 2 to 3
days (continuous sleep deprivation) Microsleeps
(2 to 3 sec long) 1. Eye lids droop 2. Less
responsive to stimuli 3. Still standing Performan
ce on complex cognitive tasks????? Performance in
motor tests???????
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• Animals.different story.Death
• Stop grooming
• Loss ability to regulate temperature
• Metabolic rate increaseseatbut never enough
• loss weight

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- Is sleep a passive? NO! Many changes in our
body during sleep Sleep is a Behavior! How do
we measure this? 1. EEG (electrical
activity) 2. Biochemically (NT) 3.
Neuroanatomically (brain structures)
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1929, a German psychiatrist Hans Berger, Found
the it was possible to record the feeble
electric currents generated on the brain,
without opening the skull, and to depict them
graphically onto a strip of paper. Berger
named this new form of recording as the
electroencephalogram (EEG, for short)
First EEG recorded by Hans Berger, circa 1928.
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• EEG (electroencephalograph)
• records electrical activity of
• the brain via electrodes
• attached to the scalp
• Gross measurement of neuronal activity
• takes an average of the whole population
• of cells in the area under the electrode
• Output of the electrodes are amplified
• and recorded
• EEGs tell you whether a person is asleep,
• awake or excited

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EEG lingo Measurement of Brain Waves
Amplitude index of voltage larger the
voltage the higher the amplitude (Height)
Frequency index of waves across time, cycles
per second (hertz, Hz) (how often they
occur)
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2 Basic EEG Patterns 1. Desynchronized neurons
in the brain firing at many different times ?
produces EEG patterns of low amplitude
high frequency (wakefulness)
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2 Basic EEG Patterns 2. Synchronized neurons
are firing at the same time produces well
defined waves of low frequency high amplitude
(characteristic of deep sleep)
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EMG Electromyogram - Leg EOG Electroculogram
- Eye muscle
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• There are two divisions of sleep
• 1. non-rapid eye movement (NREM)
• 2. rapid eye movement (REM)
• Non-Rapid Eye Movement SleepAbout 80 of adult
  sleep is NREM sleep. NREM sleep is divided into
  four stages
• Stage 1the drowsy transition from waking to
  sleeping
• Stage 2intermediate sleep, when arousal is more
  difficult
• Stage 3the beginning of "deep," or slow-wave,
  sleep
• Stage 4the deepest sleep, when there is little
  contact with external sensations

During NREM breathing, heart rates, body
temperature, blood pressure decrease.
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Resting quietly Eyes closed
Arousal awake
Transition btw wakefulness sleep
Sleeping soundly but report Not asleep at all!
Only here pre to delta
Short burst of waves 2 to 5 tx a min 1-4 (aging)
Saw Tooth
REM sleep resembles stage 1
Note that as sleep progresses from awake to
sleep, brain activity becomes more synchronized
(low frequency hi amplitude)
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90 minutes to our first bout of REM average of
5 cycles REM lasts 10-20 min then we fall back
to stage 2 and so on
somnambolism
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• REM SLEEP
• PGO spiking Pontine-Geniculate-Occipital
• Triggers the onset of REM
• 1. Waves of neural activity first in the pons
• 2. Then in the lateral geniculate
• 3. Then in the occipital cortex
• - Wave is synchronized with eye movement
• - At this time Pons is also sending inhibitory
• messages to the spinal cord ? motor
  neurons
• Neurochemistry Pons releases ACh stimulate LGN
• (inject carbacholAch agonistREM)

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Locus Coeruleus Noradrenergic neurons destroy
this area you get NO REM but SWS (stage 3 4)
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Raphe Nucleus Serontonergic neurons destroy
this area you get NO SLEEP insomniaagonistinc
rease in SWS
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Narcolepsy (hypersomnia) - sleeping disorder
(1 of 2000) characterized by periods of
irresistible sleepiness - "sleep attacks" happen
without warning and can occur even after a good
night's rest - normally last about 20 minutes -
after waking up, the person feels refreshed, only
to feel sleepy again a few hours later - There is
no known cause of this chronic sleep disorder
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Sleep apnea (Muscle atonia)
Apnea is a Greek word meaning "want of
breath disorder characterized by periods of
time when the sleeper stops breathing (apnea) or
experiences a sharp reduction in breathing
(hypopnea) These periods normally last between
10 and 30 seconds, but can last longer ? males,
overweight elderly (SIDs) The person wakes up
shortly and falls back asleep, usually not
knowing there had been any interruption in sleep
at all. These "apneic events" can occur as many
as 20 or 30 times an hour.