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Behavioral Neuroscience- Sleep


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What are the two kinds of endogenous cycles?
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
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).
What happened in hamsters whose DARK SHIFT were changed to 8 hours earlier? what about those who ran for seven hours?
They slowly changed their sleep time to fit the dark changes but the process took 10 days.
Thier cycle was fixed after one day.
Tips to resetting your biological clock?
- exposure to light
- adhere to new cycle
- take melatonin before sleep
- take melatonin in morning
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
Ingested melatonin

-for what?
- reports say?
- dosages
to promote sleep

Safe but ineffective (10% ineffective 10% report nightmares)

vary (.3 to 5 mg)
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.
What is the evolutionary argument for sleep? How is it not supported?
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.
What is the modern theory of Why we sleep?
Evolutionary arguments (to conserve energy and to avoid predation) are paired with restorative functions (brain needs to rejuvenate) to determine our need for sleep.

- records what
- shows peaks when
Electric potential in a particular part of the brain.

Neurons fire in synchrony.

Alpha (freq, state, describe)
- regular jagged (8-12 Hz)indicate relaxation

- smallest waves (13-30 Hz) indicate active arousal.

- Larger waves, irregular waves, 5-8 Hz, slow-wave and REM sleep

- largest waves, 1-4 Hz, deep slow-wave sleep.
When a person is awake what waves would one expect to see on their EEG? Asleep?
Awake: Alpha and Betta waves

Sleep: Theta and Betta (dreams)
Synchrony vs Desynchrony

- voltage
-speed of neural firing
- wave size
- state of arousal

- low frequency, high voltage, large waves, slowly firing together, deep sleep or coma


higher frequency, lower voltage, smaller waves, faster not togeter, awake
Stage 1 sleep

-characterized by ____ waves
- purpose?
- lasts how long?
- dreaming?
Transfer from wake to sleep
10 minutes
NONE; random thoughts
Sleep 2 cycle

-sleep characterized by what waves?
- time?

decreases sensory input and keeps person asleep.

15 minutes
Another important part of stage 2 sleep. what is it? what is it believed to do?
K complex; thought to promote deep sleep.
Stage 3 sleep

- what waves?
- time?
- what kind of sleep?
25-50% delta, very slow and synchronous.

30-45 minutes

Deep sleep
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.
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.
What is the nightly progression of sleep?
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.
Cervou isole preparation

-transection where?
- results in what EEG activity?
- interupted by?
midcollicular transection

slow-wave synchronous activity (sleep-like).

Olfactory and visual stimuli
Passive sensory theory

-what does it say?
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.
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.
Partial cerveau isole

midcollicular transection

caused slow wave EEG paterns only if transection included reticular formation.
What results confirmed the role of the reticular formation in sleep?
Sleeping cats were awaken by electrical stimulation of the reticular formation.
the reticular formation

-found between
- produces what
the two previous preparations (cerveau and encephale)

wakefulness-producing area.
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.
Many brain structures (4) are considered to be involved in arousal (waking up, attention, memory, motivation). What are they?
Reticular formation

+locus coerruleus
+basal forebrain
Raphe nuclei

-What kind of NT neurons
-lesions produce
midline of caudal reticular formation.

Serotenergic neurons

Complete insomnia
Basal forebrain nuclei

-lesion causes
-stimulation causes
disrupts sleep

stimulation does NOT produce sleep.

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)
Why it is believed sleep occurs in REM sleep.
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!
What is the role of the pons in sleep?
Inhibits major muscles during REM sleep. Also originates Pons geiculate occipital waves (PGO waves).
PGO Waves

- pattern of wave
- found where first
- found where second
Large amplitude waves


Lateral geniculate nucleus (Visual) then to the occipital lobe and finally the thalamus and cortex.
In patients with REM deprivation, what is found in the activity of PGO waves?
PGO waves start early before REM stage (stages 2 and 4). Maybe even during wake cycles (hallucinations).
True/False: external stimulation can be incoorporated in dreams?
True/False: Dreams last only an instant
False. Wake a person in REM and they can fairly accurately tell you how long theyve been dreaming.
True/False: Everybody dreams
True/False: penile erection/vaginal secretions suggests dreams had sexual content.
Not necesarilly.
True/False: Sleepwalking (somnambulism) occurs during dreaming.
False. Recall dreams only occur during REM. Recall durng REM muscles are flaccid.
REM deprivation symptoms:
-impaired concentration
-INCREASED apetite
Non-REM deprivation symptoms
What else is REM believed to be responsible for?
Memory- the process of memory.

Research shows that it only aids in skill learning not fact learning.
What does the activation synthesis hypothesis suggest is how the brain causes dreams?
Brain synthesizes random neuronal activity into a story.

Brain is aroused during REM but body is "shutdown" so the brain processes memories.
Disorders of sleep

Onset insomnia
-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.
Sleep disorders

Maintenance insomnia

-characterized as
-often found in ______ individuals
-relation to
difficulty mantaining sleep

prolonged sleep apnea


relation to SIDS (?)
Sleep disorder

Termination insomnia
Difficulty sleeping for long enough periods of time.

Desynchronized circadian rhythms.
Sleep disorders

Night terrors

-characterized as
Extreme fear (not nightmare). Extremely anxious during non REM sleep
Sleep disorder

REM Behavior disorder

-characterized as
- results from damage to the
Very vigorous acting out of dreams

Damage to the pons.
Sleep disorders

Sleep walking
-occurs when in the night
-harmful to wake?
early in the night during stages 3 and 4


Sleep disorders


-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.
In dogs the cause of cataplexy was found to be...
Deficiency of hypocreatin secreting neurons.

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