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54 Cards in this Set
- Front
- Back
What are the two kinds of endogenous cycles?
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Circannual cycles- endogenous annual cycle in preparation for annual events such as migration, hibernation.
Circadian- daily cycles like sleep/wakefulness, many hormomones such as corticosterone (peaks at |
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Free running daily acitivity cycles
-span how long? -show what? -how are they synchronized? |
about 25 hours
humans naturally have app 25 hour daily cycles when not regulated by environement environmental cues (mainly light). |
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What happened in hamsters whose DARK SHIFT were changed to 8 hours earlier? what about those who ran for seven hours?
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They slowly changed their sleep time to fit the dark changes but the process took 10 days.
Thier cycle was fixed after one day. |
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Tips to resetting your biological clock?
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- exposure to light
- adhere to new cycle - take melatonin before sleep - take melatonin in morning - EASIER TO GO WEST! |
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What brain structure is responsible for resetting clocks, generating rhythms for body temp and sleep?
-where is it found -when is it active/inactive? - inputs - outputs |
Suprachiasmatic nucleus
anterior to the optic chiasm (from vision chapter) active= day inactive= night inputs- retinohypothalamus outputs- pineal gland |
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What role does the pineal play in restting the clocks?
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It recieves information from the suprachiasmatic nucleus.
It is responsible for releasing melatonin to induce sleep (humans @ night; rats during day). |
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Melatonin
-synthesized from - what supreses its secretion - secretion increases when - peak @ - melatonin causes responsible for what else |
Serotonin
Low frequency E fields, and LIGHT. Just after nightfall 3 AM breeding cycles (as light changes due to seasons). |
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Ingested melatonin
-for what? - reports say? - dosages |
to promote sleep
Safe but ineffective (10% ineffective 10% report nightmares) vary (.3 to 5 mg) |
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Repair and restoration theory
-what does it suggest? -sleep deprivation - results? - |
Sleep allows the body and brain to rest and rejuvenate
deprivation causes hallucinations, irratibility, dizziness, tremors, impaired cognition Results suggest NOT TRUE. No long sleep is necessary for functioning. |
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What is the evolutionary argument for sleep? How is it not supported?
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Evolution suggests that early humans had enough ti,e to accomplish everything and slept to avoid predation. In fact foragers sleep at night, while, predators sleep during day.
However, some animals for whom sleep is NOT advantageous still do. Also sleep deprivation causes impairments. |
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What is the modern theory of Why we sleep?
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Evolutionary arguments (to conserve energy and to avoid predation) are paired with restorative functions (brain needs to rejuvenate) to determine our need for sleep.
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EEG
- records what - shows peaks when |
Electric potential in a particular part of the brain.
Neurons fire in synchrony. |
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WAVES
Alpha (freq, state, describe) Beta Theta Delta |
Alpha
- regular jagged (8-12 Hz)indicate relaxation Betta - smallest waves (13-30 Hz) indicate active arousal. Theta - Larger waves, irregular waves, 5-8 Hz, slow-wave and REM sleep Delta - largest waves, 1-4 Hz, deep slow-wave sleep. |
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When a person is awake what waves would one expect to see on their EEG? Asleep?
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Awake: Alpha and Betta waves
Sleep: Theta and Betta (dreams) |
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Synchrony vs Desynchrony
-frequency - voltage -speed of neural firing - wave size - state of arousal |
Synchrony
- low frequency, high voltage, large waves, slowly firing together, deep sleep or coma Desynchrony higher frequency, lower voltage, smaller waves, faster not togeter, awake |
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Stage 1 sleep
-characterized by ____ waves - purpose? - lasts how long? - dreaming? |
Theta
Transfer from wake to sleep 10 minutes NONE; random thoughts |
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Sleep 2 cycle
-sleep characterized by what waves? -purpose? - time? |
theta
decreases sensory input and keeps person asleep. 15 minutes |
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Another important part of stage 2 sleep. what is it? what is it believed to do?
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K complex; thought to promote deep sleep.
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Stage 3 sleep
- what waves? - time? - what kind of sleep? |
25-50% delta, very slow and synchronous.
30-45 minutes Deep sleep |
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Stage 4 sleep
- waves? - time? - purpose? - |
Similar to stage 3 except more than 50% waves= delta
30-45 minutes Lowers heartrate, breathing and makes slower and larger waves on EEG. |
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REM Sleep
- onset after stage 1? - what is different in REM than in the other cycles? - what happens to EEG activity? |
60-90 minutes after the start of stage 1 sleep.
Dreaming; also muscles are flaccid. EEG activity is more alert- desynchronous smaller waves. |
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What is the nightly progression of sleep?
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First 60-90 minutes= stages 1-4
Next 60-90 minutes= REM sleep Sequence repeats with stages 3 and 4 dominating early sleep while stage 2 and REM dominating later in the night. |
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Cervou isole preparation
-transection where? - results in what EEG activity? - interupted by? |
midcollicular transection
slow-wave synchronous activity (sleep-like). Olfactory and visual stimuli |
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Passive sensory theory
-what does it say? -TRUE/FALSE |
It suggested that the reason we fall asleep is because of lack of sensation.
NOT TRUE. Even with continuous stimulation the body will still sleep. |
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encephale isole preperation
-teransection where? - results - what does this mean? |
caudal brainstem
does NOT intterupt sleep/wake patterns Therefore that which controls sleep must be somewhere between the two transections. |
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Partial cerveau isole
-transection? -results? |
midcollicular transection
caused slow wave EEG paterns only if transection included reticular formation. |
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What results confirmed the role of the reticular formation in sleep?
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Sleeping cats were awaken by electrical stimulation of the reticular formation.
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the reticular formation
-found between - produces what |
the two previous preparations (cerveau and encephale)
wakefulness-producing area. |
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Reticular formation
- positions and connections - single control? |
The reticular formation is in the perfect position to control sleep it has axons from the frontal cortex to the medulla and from the medulla to the spine.
However, like vision, hearing and movement it is not controlled at one locus. |
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Many brain structures (4) are considered to be involved in arousal (waking up, attention, memory, motivation). What are they?
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Reticular formation
+locus coerruleus +hypothalamus +basal forebrain |
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Raphe nuclei
-Where -What kind of NT neurons -lesions produce - |
midline of caudal reticular formation.
Serotenergic neurons Complete insomnia |
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Basal forebrain nuclei
-lesion causes -stimulation causes |
disrupts sleep
stimulation does NOT produce sleep. IN OTHER WORDS INVOLVED IN MANTAINING SLEEP NOT STARTING IT. |
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REM Sleep
-increases in what areas of brain? -decreases in activity where in brain? |
decreases in the activity of the frontal cortex. (especially Dorsal Lateral prefrontal cortex)
Increases in amydala, pons, medula, thalamus (AMPT) |
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Why it is believed sleep occurs in REM sleep.
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Activity increases in amygdala. Amygdala responsible for emotion and dreams are emotional.
Also inactivation of the dorsal lateral prefrontal cortex causes incoherence in memories and random thought. JUST LIKE THOSE IN DREAMS! |
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What is the role of the pons in sleep?
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Inhibits major muscles during REM sleep. Also originates Pons geiculate occipital waves (PGO waves).
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PGO Waves
- pattern of wave - found where first - found where second |
Large amplitude waves
Pons Lateral geniculate nucleus (Visual) then to the occipital lobe and finally the thalamus and cortex. |
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In patients with REM deprivation, what is found in the activity of PGO waves?
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PGO waves start early before REM stage (stages 2 and 4). Maybe even during wake cycles (hallucinations).
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True/False: external stimulation can be incoorporated in dreams?
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True
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True/False: Dreams last only an instant
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False. Wake a person in REM and they can fairly accurately tell you how long theyve been dreaming.
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True/False: Everybody dreams
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True.
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True/False: penile erection/vaginal secretions suggests dreams had sexual content.
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Not necesarilly.
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True/False: Sleepwalking (somnambulism) occurs during dreaming.
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False. Recall dreams only occur during REM. Recall durng REM muscles are flaccid.
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REM deprivation symptoms:
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-dizziness
-impaired concentration -tremors -hallucinations -irritability -anxiety -INCREASED apetite |
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Non-REM deprivation symptoms
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None
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What else is REM believed to be responsible for?
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Memory- the process of memory.
Research shows that it only aids in skill learning not fact learning. |
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What does the activation synthesis hypothesis suggest is how the brain causes dreams?
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Brain synthesizes random neuronal activity into a story.
Brain is aroused during REM but body is "shutdown" so the brain processes memories. |
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Disorders of sleep
Onset insomnia -difficulty -due to -may also include |
Difficulty getting to sleep
Desynchronation of circadian rhythms. or tolerance to sleeping pills. Periodic leg movement disorder (PLMD): involuntary kicks and thrashing at sleep onset. |
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Sleep disorders
Maintenance insomnia -difficulty -characterized as -often found in ______ individuals -relation to |
difficulty mantaining sleep
prolonged sleep apnea obese relation to SIDS (?) |
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Sleep disorder
Termination insomnia -difficulty -cause |
Difficulty sleeping for long enough periods of time.
Desynchronized circadian rhythms. |
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Sleep disorders
Night terrors -characterized as |
Extreme fear (not nightmare). Extremely anxious during non REM sleep
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Sleep disorder
REM Behavior disorder -characterized as - results from damage to the - |
Very vigorous acting out of dreams
Damage to the pons. |
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Sleep disorders
Sleep walking -occurs when in the night -harmful to wake? |
NOT REM
early in the night during stages 3 and 4 FAMILIAL AND USUALLY IN CHILDREN. NO. |
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Sleep disorders
Narcolepsi/Cataplexy -characterized by -brought on by -genetic disorder? -narcoleptics skip what sleep cycle |
REM-like paralysis
strong emotions yes causing brain dysfunction skip slow-wave sleep. |
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In dogs the cause of cataplexy was found to be...
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Deficiency of hypocreatin secreting neurons.
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