bio 16

-is characterized by the absence of behavior.

-during sleep, there is a higher threshold for arousal by external stimuli

-NAthaniel Kleitman from U of C

*used his graduate students as testers

• -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

-recordings of eye movement

-recordings of muscle tension

-slow-wave sleep and

-Rapid-eye movement (REM) sleep

• -low amplitude, high frequency activity
• *15-20 HZ

-awake and alert

• -relaxed conditions, with eyes closed
• *also stage 1 and 2

• -activity becomes more synchronized and a distinct rhythm emerges
• *8-12 HZ
• 

-"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

• -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

• -delta waves start to appear
• *have a frequency of 1 hz

-summary of each stage

progression through SWS 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

-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

• -widely believed to occur during REM and dreaming
• *not true

-sleep walking and talking occur most often during state 4SWS

• SWS and REM sleep
• *exceptions are echidna and dolphin
• **REM and SWS developed more than 150 years

-theymust deciede when to come up for air

-they solve this problem by permitting one side of sleep to sleep at a time

animals with high metabolic rates have short sleep cycles abd animals with low metabolic rates have long sleep cycles

90-110 minutes

*in rats: 10-11

until 16 weeks of age

• infants to elderly
• 

-less REM sleep

-more waking episodes

• -dramatic reduction in stage 3 and 4
• *which correlates with reduced cognitive abilities and senile dementia

-investigating sleep disorder narcolepsy

-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

-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

-sudden loss of muscle tone leading to collapse of body eithout a loss of consciousness

• -can be triggered by strong emotional triggers
• *laughter
• *anger

-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

90% of their hypocretin neurons

preventing sleep and the transition from wakefulness to REM

hypothalamus

-basal forebrain

- reticualr formation

-pons

• temporarily inaility to move or talk either just beofre falling asleep or just after waking up
• *last few minutes

-pontine nuclei continuing to impose paralysis when one is awoken from REM

-inability to fall asleep or remain asleep

-15-30 % of adult population

-shift work

-time zone changes

• -environmental conditions
• *sleeping in new place

-trouble remaining asleep

-typically go hand in hand with respiratory disorders such as 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

jgb