Sleep-ARS Flashcards by Brandon edlund

What are the basic EEG rhythms or patterns, and the changes that occur during a seizure?

Absence seizure - spike-wave

Complex partial - (focus where it starts) very small crazy amplitudes

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What is an EEG?

Electroencephalography

Non invasive measurement of brain activity

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What are the stages of sleep?

Awake

Drowsy

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What are the patterns of sleep and the EEG that patterns that characterize them?

Awake - alpha waves
Stage I (drowsy) - beta waves
Stage II - sleep spindles (higher amp and freq, onset of coherence, driven by Thalamiccortical oscillations)
Stage III - theta?
Stage IV - delta
REM - very much like awake, essentially beta waves

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What are the patterns of sleep and the EMG that patterns that characterize them?

Waking - high muscle tone
Non-REM - highish muscle tone
REM - almost no muscle tone

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What are the patterns of sleep and the ELectrooculogram that patterns that characterize them?

Waking - Saccades (random peaks, high freq)
Non REM - rolling motion of eyes (medium amplitude highish freq)
REM - Saccades come back (big peaks, low freq)

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What are the circuits responsible for sleep/wake transitions, including the ascending reticular activating system and the region that promote slow-wave sleep?

ARAS - nuclei from the braimstem (pontine nuclei), hypothalamus, basal forebrain –> cortex and thalamus

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What are the possible functions of sleep?

Reducing energy expenditure 
Replenish brain glycogen
Cognition
- brain plasticity 
- consolidation, memories, association, 
- consolidation of learning 
Possibly allows shrinkage of neurons and metabolizes to be drained out

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What are the effects of sleep deprivation?

Short term: cognitive impairment
- reaction time
- judgment 
Long term
- cognitive decline (dementia)
- Problems with homeostasis 
- infection
- hallucination, seizures
- death
REM sleep is not necessary
Stage III and IV is necessary

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What is the relationship between the functions of sleep disturbances and other clinical disorders?

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How does an EEG work?

Works by receiving the electric field of pyramidal cells on the cortex

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What is the big dip in and EEG normally?

Eye blinks

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What are the axis for EEG?

1sec - x

100uV - y

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What are beta waves on a EEG?

Tiny peaks becaus you get lots of info in that cancel each other out, also why the frequency is high because things are in sync
Active thinking

Freq 12-30
Amp 30

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What are alpha waves on an EEG?

Eyes closed
Less info coming in
Larger regions of the cortex are being activated together so you get larger amplitudes but a lower frequency

Freq - 8-12
Amp - 10-50

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What are theta waves on an EEG?

Drowsiness or meditation

Freq - 4-8
Amp - 50-100

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What are delta waves on an EEG?

Slow-wave sleep

Freq less than 4
Amp - 100-150

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Is coherence in cortical states a good thing?

Not always, that is a seizure

Very coherent spike-wave repeat
Absence seizure - eye blinking, loss of consciousness

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What is driven by Thalamocortical oscillations?

Sleep spindles in stage II

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What stage of sleep is restorative?

Stage four

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What do you see with sleep apnea?

When you lose tone in the palate it collapes

Stay mostly awake

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What are the two tracts that project into the sleep wake cycle?

Thalamocortical

Corticothalamic

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What give you the particular EEG patterns?

Firing from the Thalamocortical and corticothalamic tracts

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What does the ARAS use for transmission?

Monoamines

ACh

What are the monoaminergic nuclei and what do they produce?

Tuberomammillary nucleus - HA SN/ventral tegmental area - DA Locus ceruleus - NE Raphe nuclei - 5-HT

What neurotransmitter is related to wakefulness?

Histamine

What are the Cholinergic nuclei?

BF - basal forebrain LDT - laterodorsal tegmental nucleus PPT - pedunclopontine tegmental nucleus

What does the ARAS promote?

Wakefulness

What are the ARAS nuclei that mainly project to the thalamus?

LDT and PPT

What is the function of the ARAS nuclei?

Modulate the cortex

What are the two different lateral hypothalamus neurons?

Orexin (hypocretine) MCH (REM sleep) Both neuropeptides

What is orexin?

Sustains wakefulness and projects to all ARAS nuclei

What happens when you lose orexin?

Narcolepsy Parietal loss in Parkinson's and brain trauma Orexin antagonists may be used as sleep aids

What does the preoptic nuclei do?

Two of them: VLPO MNPO Promotes sleep

What neurotransmitters does the preoptic nuclei (VLPO, MNPO) have?

GABA and galanin

Where does the preoptic area project?

ARAS and orexin neurons and inhibits them

Where does the Thalamocortical circuit project from the thalamus?

Th thalamic reticular nucleus. Wraps around the whole nucleus. INHIBITORY and the others are excititory

What contributes to sleep spindles and waves?

He Thalamocortical circuit

Do you dream during non-REM sleep?

Less frequent, vivid, and emotional than during REM Less memorable

What is bursting mode of the thalamus?

Reticular cell fires in a burst --> inhibits Thalamocortical cell (hyperpolarization) --> bursts of action potentials --> excites pyramidal cell in cortex --> cortex projects back to thalamic cortical cell and prevents burst (depolarized) and also fires to the reticular cell and makes a cycle This leads to coherent activity in the cortex. This is how we get slow sleep

What happens during REM sleep?

The preoptic nuclei a subset stops inhibits the LDT and the PPT which allows sensory transmission to the cortex (some sensory) Leads to dreams

What area of the brain is inhibited during REM and what does it do?

Dorsaolateral prefrontal cortex | Gives impulse control and judgment (social control)

What does the anterior cingulate cortex do?

Smilingly emotional facial expression

What does the parahippocampal gyrus do?

A lot with memory

What gives you beta waves during rem?

Subset of LDT/PPT (rem on)

What is the REM off switch?

LC/Raphe (part of ARAS)

What may be the first symptom of Parkinson's and levy body dementia?

REM behavior disorder

What is REM behavior disorder?

Loss of rem atonia More common in old people 80% of Pxs later develop alpha-synucleinopathies

What are the REM on neurotransmitters?

ACh and MCH

What are the rem-off neurotransmitters?

Monoamines

What neurotransmitter is present during REM and waking?

ACh

What neurotransmitter is present only during waking?

Orexin

What neurotransmitters are the monoamines in sleep-wake cycle?

Serotonin NE DA HA

What has orexin?

Lateral hypothalamus

What does the lateral hypothalamus have?

MCH and orexin, waking and rem

What metabolizes are cleared during sleep?

Beta amyloid

What is the "somnogen" hypothesis?

Accumulation of diffusable or circulating factors promotes sleep - adenosine is one possible somnogen (Byproduct of ATP use --> binding inhibits ARAS --> dis inhibition of VLPO(sleep switch) --> sleep

What does caffeine do?

It is an antagonist of adenosine receptors

What does the preoptic nuclei release?

GABA and galanin make you sleep