Sleep Flashcards by Mathilde R

electroencephalogram (EEG)

We measure brain activity in sleep by attaching electrodes to the scalp to record an electroencephalogram (EEG). Cap with metal wires, each will pick up electrical fluctuation corresponding to the neuron activity beneath the skull.

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electromyogram (EMG)

We measure muscle activity by attaching electrodes to the chin to record an electromyogram (EMG). Moving indicates activity, also muscle tone (maintaining body posture).

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electro-oculogram (EOG).

Electrodes are also placed near the eyes to measure eye movements via an electro-oculogram (EOG).

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Rapid eye movement (REM)

Desynchronized EEG activity, rapid eye movements, dreaming, and muscle paralysis; muscles are totally inactive apart from occasional twitches.

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In REM, cerebral blood flow and oxygen consumption ___increases/decreases

Increases

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In REM, you are easily _____.

Aroused

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Within 20 minutes of sleep, we immediately go into ____ sleep for 1 hour

Deep

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First half of night is a lot of ___ sleep, the second is a lot of ____.

Deep, REM

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Muscle tone is lost in this stage of sleep.

REM

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Beta activity

13–30 Hz; typical of an aroused state. It reflects desynchronous neural activity (high frequency, low amplitude oscillations)

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Alpha activity

8–13 Hz; typical of awake person in a state of relaxation (bit more coordinated).

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Theta activity

4–8 Hz; appears intermittently when people are drowsy, and is prominent during early stages of sleep. More coordinated. Bigger amplitudes.

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Delta activity

<4 Hz; occurs during deepest stages of slow-wave sleep; reflects synchronized low frequency, large amplitude brain activity. All neurons are kind of following the same pattern.

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The pattern of neural activity on EEG reflects synchronized bursts of ____ _____ in large collections of neurons (6 electrodes with tips in nearby neurons).

Action potentials

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In upward swing, ____smaller/larger amplitude are when all neurons are having action potentials at the same time. (all spiking or not spiking)

Larger

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_____low/high wave sleep is stage 3 of non-REM sleep (also known as deep sleep). It corresponds to large amplitude, low frequency oscillations of brain activity as measured with EEG.

Low

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Awake, neurons all fire at their own rate with ___low/high amplitude. The frequency and oscillation more common awake is between 10-30HZ

Low

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As a general rule, predatory animals indulge in ____short/long periods of sleep. Animals that are preyed upon typically sleep during ____short/long intervals that may

Long, short

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The amount of time a species sleeps each day is _____positively/negatively correlated with weight.

Negatively. The larger animal, the less sleep they get.

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Overall metabolic rate _____ as mass increases, but metabolic rate per pound (or per cell) ______as mass increases.

Increases, decreases

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The bigger you are, the ____less/more energy you burn off

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The bigger the animal, the _____worse/better at regulating temperature.

Better

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The bigger you are, the ___less/more efficient you are.

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↑ brain mass =

↓ heart rate, ↑ life span, ↓ total sleep time

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Large animals benefit from economies of ____ (i.e. heat savings and more efficient distribution networks), so each cell doesn’t have to work as hard as it does in a small animal.

Scale

The amount of slow-wave and REM sleep people get correlates with improvements in _____ and ______ memory, respectively.

Declarative and procedural

Overtime, the neural network is becoming more excitable on average during the day which increase the risk of _____.

Seizure

Some evidence suggests sleep is required for the efficient removal of ____ products from the brain.

Waste

The concentration of many proteins in the cerebrospinal fluid of the brain ____ across periods of wakefulness and _____ across periods of sleep.

Increases and decreases

When animals sleep, ___ cells in the brain (astrocytes) seem to lose water and shrink in size.

Glial

Astrocytes shrinking increases the total volume of _____ space (i.e., extracellular solution), which promotes diffusion of cerebrospinal fluid through the brain, clearing away waste much more rapidly.

Interstitial

Larger brains seem to have more space to _____ garbage, and they can clear away waste faster than smaller brains.

Accumulate

The _____ system clears waste product in our body

Glymphatic

Cerebrospinal fluid (CSF)

Clear, colorless fluid that is continually being made in brain ventricles.

CSF circulates around the brain and diffuses into the _____ space, thus becoming the extracellular solution that surrounds neurons.

Interstitial

As CSF moves through the interstitial space, it clears waste products away before exiting into ....

Blood vessels.

The glymphatic system removes excess ____ and other waste from the interstitial space of the brain.

Proteins

Almost all signaling molecules in the brain act via ______

Diffusion

Circadian rhythm

Changes in behaviour and physiology that follow a 24-hour cycle.

Circadian rhythms are controlled by...

Internal biological clocks that continue to run in the absence of light, but daily variation in light levels keep the clock adjusted to 24 hours.

If the light is constantly dim, rats largely maintain their circadian rhythms, but these rhythms ____ slightly over time (23 or 25 hour cycles).

Drift

Most mammals are active at ___day/night.

Night

The suprachiasmatic nucleus (SCN) of the hypothalamus regulates ...

circadian rhythms (our inner clock).

A small group of cells behind the ___ ____ synapses to the SCN: direct information from the eyes

Optic chiasm

Lesioning the SCN dramatically alters circadian rhythms such as ...

sleep-wake cycles and hormone secretions

SCN lesions alter the ____ and ____ of sleep-wake cycles, but they do not change the total amount of time that animals spend asleep.

Length and timing

Circadian rhythms are maintained by the production of several ___ and two interlocking feedback loops.

gene

When expression of one ____ gets high enough, it inhibits its own production and promotes the expression of a different _____ . That _____ will turn on 12 hours, the other will turn on the other

Protein

Advanced sleep phase syndrome

A mutation of a gene called per2 (period 2) causes a 4-hour advance in the biological clock (rhythms of sleep and temperature cycles) – a strong desire to fall asleep at 7pm and wake up at 4am.

Delayed sleep phase syndrome

a mutation of a gene called per3 causes a 4-hour delay in rhythms of sleep and temperature cycles– a strong desire to fall asleep at 2am and wake up at 11am.

A build-up of many molecules in the _____ fluid of the brain during waking hours promote drowsiness and sleep at high concentrations. They are cleared away during sleep.

Interstitial

Adenosine molecule

Adenosine levels rise in the brain during waking hours and accumulate even more with sleep deprivation. Adenosine levels fall rapidly in the brain during sleep, even during brief intrusions of sleep.

Drowsiness and the duration and depth of sleep are strongly modulated by ______ receptor signaling throughout the brain

Adenosine

Caffeine, which promotes arousal, is an adenosine receptor ____agonist/antagonist.

Antagonist

Signaling molecules released by neurons that show increased activity during periods of arousal, alertness, and wakefulness and decreased activity during slow-wave sleep.

Serotonin (raphe nuclei in the hindbrain) Norepinephrine (locus coeruleus in the hindbrain) Acetylcholine (throughout the brain) Orexin (hypothalamus) Histamine (hypothalamus)

Orexin and histamine are _____ that are released by neurons in the hypothalamus.

Neuropeptides

Histamine receptor blockers (antihistamines) often cause _____.

Drowsiness

Neurons in the ____ of the hypothalamus promote sleep.

ventral lateral preoptic area (vlPOA)

Electrical stimulation of this area causes drowsiness and sometimes immediate sleep. Lesions suppress sleep and cause insomnia.

ventral lateral preoptic area (vlPOA)

flip-flop circuit

vIPOA neurons inhibit wake-promoting neurons. But this area receives inhibitory inputs from the same regions it inhibits. Both regions cannot be active at the same time and the switch from one state to another is fast.

The animal is awake when the arousal, wake-promoting system is more ____than the vlPOA neurons.

Active

The animal is asleep when vlPOA neurons are more ____ than the wake-promoting arousal system.

Active

Sleep-promoting vlPOA neurons are activated by ____ signaling.

Adenosine

Arousal-promoting _____ (ACh) neurons are inhibited by adenosine signalling.

Acetylcholine (ACh)

When the clock of SCN neurons aligns with the build-up (or clearance) of _____ molecules, the whole network flip-flops and the animal transitions into (or out of) sleep.

Sleep-promoting

Orexin (hypocretin)

Peptide produced by neurons in the lateral hypothalamus (LH). Orexin neuron activity promotes wakefulness. Motivation to remain awake activates orexin neurons.

Narcolepsy

A rare sleep disorder characterized by periods of excessive daytime sleepiness and irresistible urges to sleep.

Cause of narcolepsy

Death of orexin neurons in the hypothalamus. They seem to be attacked by the person’s own immune system, usually during adolescence or young adulthood.

Sleep paralysis

when REM-associated paralysis occurs just before a person falls asleep or just after they wake up. It is often accompanied by vivid, dream-like hallucinations.

Cataplexy

When complete muscle paralysis suddenly occurs when someone is awake. It is typically precipitated by strong emotional reactions or sudden physical effort (e.g., laughter, anger, excitability

Insomnia

Difficulty falling asleep after going to bed or after awakening during the night

Fatal Familial Insomnia & Sporadic Fatal Insomnia

A very rare disease that involves progressively worsening insomnia, which leads to hallucinations, delirium, confusion states, and eventually death (within a few years).

Cause of Fatal Familial Insomnia & Sporadic Fatal Insomnia

Progressive neurodegeneration around the thalamus, hypothalamus, and/or brain stem.

Sleep terrors

Characterized by overwhelming feelings of terror upon waking. May include panic and screaming and bodily harm caused by rash actions. People sometimes have no recollection of these events. Prevalent in people diagnosed with post-traumatic stress disorder (PTSD).

REM sleep behavior disorder

Neurological disorder in which the person does not become paralyzed during REM sleep and thus acts out dreams, beurodegenerative disorder with at least some genetic component * It is often associated with more common neurodegenerative disorders such as Parkinson's disease

Sleep Flashcards

(75 cards)