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What is sleep? (2)
-is characterized by the absence of behavior.
-during sleep, there is a higher threshold for arousal by external stimuli
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Who contributed to sleep research?
-NAthaniel Kleitman from U of C
*used his graduate students as testers
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(types of recordings) What is Electroencephalography (EEG) ?
- -averages the activity of hundreds to thousands of individual neurons.
- *similar to recording the activity of individual neurons like we've seen in vision lectures
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(types of recordings) What is Electro-oculography (EOG)?
-recordings of eye movement
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(types of recordings) What is Electromyography (EMG)?
-recordings of muscle tension
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Which two major classes of sleep have been descoverred?
-slow-wave sleep and
-Rapid-eye movement (REM) sleep
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Description of beta activity
- -low amplitude, high frequency activity
- *15-20 HZ
-awake and alert
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Description of alpha acitivty (2)
- -relaxed conditions, with eyes closed
- *also stage 1 and 2
- -activity becomes more synchronized and a distinct rhythm emerges
- *8-12 HZ

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(stages of sleep) Stage 1- 6 characteristics
-"slow-wave sleep"
-alpha rhythm (8-12 hz)
-EEG shows smaller amplitude and irregular frequency
- -occasional sharp waves
- *vertical spikes
-slower heart rate, reduced muscle tension
- -eyes start to roll about slowly
 - *last several minutes before they enter 2nd stage
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(stages of sleep) Stage 2 (3)
- -characterized by the occasional appearences of high frequency EEG
- *sleep spindles
- *k complex
- **alpha rhythm interupted ocassionaly by these two
-alpha rhythm
-when people wake up from stage 1 or 2, they often do not acknowlege that they have been sleeping
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(stages of sleep) Stage 3
- -delta waves start to appear
- *have a frequency of 1 hz
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(progression of stages) during first hour of sleep there is an orderly...
progression through SWS stages
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progression steps through stages
- 1. first stage then goes in numerical order to 4, then back to one
- *once it starts over to one, it shows different EEG patterns than initial stage 1
- **referred to as emergent stage, EEG
2. after the second turn through stages, after first stage, REM stage will appear
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(REM) Characteristics of REM stage
-EEG pattern resembles that of an awake state
-EMG recordings show muscles are completely flaccid (relaxed)
-irregular breathing, and pulse rate
-vivid dreams occur during REM
-rapid eye movements under the eyelids
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(sleep walking) Somnambulism
- -widely believed to occur during REM and dreaming
- *not true
-sleep walking and talking occur most often during state 4SWS
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MOst mammals as well as birds exhibit periods of...
- SWS and REM sleep
- *exceptions are echidna and dolphin
- **REM and SWS developed more than 150 years
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Dol[hins and whales and SWS and REM
-theymust deciede when to come up for air
-they solve this problem by permitting one side of sleep to sleep at a time
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sleep duration is linked to metabolism
animals with high metabolic rates have short sleep cycles abd animals with low metabolic rates have long sleep cycles
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sleep cycles typically last from...
90-110 minutes
*in rats: 10-11
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what age do sleep patterns rise?
until 16 weeks of age
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REm levels rise from...
- infants to elderly

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sleep patterns as we age
-less REM sleep
-more waking episodes
- -dramatic reduction in stage 3 and 4
- *which correlates with reduced cognitive abilities and senile dementia
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How was the role of hypothalamus discovered in sleeping?
-investigating sleep disorder narcolepsy
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NArcolepsy characteristics (4)
-last anywhere between 5 to 30 mins
-can occur anytime during wake hours
-con occur every 90 mins
-1 of every 2000 americans suffer narcolepsy
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hallmarks of narcolepsy
-manifests between ages of 15 and 25
-they enter REM within few minutes of falling asleep
-exhibit normal sleep patterns at night
-accmpanied by cataplex
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whats cataplex?
-sudden loss of muscle tone leading to collapse of body eithout a loss of consciousness
- -can be triggered by strong emotional triggers
- *laughter
- *anger
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HYpocretin and narcolepsy
-mutation in genes might be responsible
ex)mice that lacked hypocretin displayed narcolepsy
ex) normal rats can be made narcoleptic when ejected toxin that attacks hypocretin
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Humans that exhibit narcolepsy have lost..
90% of their hypocretin neurons
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hypocretin is responsible for...
preventing sleep and the transition from wakefulness to REM
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where is hypocretin made and releaseed?
hypothalamus
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(hypothalamus and hypocretin) cell bodies of neurons project to other 3 regions involved in sleep
-basal forebrain
- reticualr formation
-pons
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Sleep paralysis characteritics
- temporarily inaility to move or talk either just beofre falling asleep or just after waking up
- *last few minutes
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what causes sleep paralysis?
-pontine nuclei continuing to impose paralysis when one is awoken from REM
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Insomnia
-inability to fall asleep or remain asleep
-15-30 % of adult population
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sleep onset insomnia
-shift work
-time zone changes
- -environmental conditions
- *sleeping in new place
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sleep-maintenence insomnia
-trouble remaining asleep
-typically go hand in hand with respiratory disorders such as sleep apnea
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Sleep apnea
- person stops breathing several times a night
- *results from tongue and throat blocking airways from atonia
- *could be due to CNS failing to stimulate breathing
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