Sleep and Biological Rhythms Flashcards
What is the correct sequence of protein synthesis of DNA?
DNA > Transcription > RNA > Translation > Protein.
What is the path that an action potential takes?
From the cell body along the axon to the synapse.
How is sleep studied typically?
In a sleep laboratory.
What is a polysommnogram?
It is a method used to study sleep.
What does a polysommnogram record?
It records multiple traces of sleep.
Define sleep.
Sleep is a behaviour and is characterised by the instant urge of sleepiness which forces humans to find a quiet place to rest.
What are six different methods to study sleep?
- EEG
- EMG
- ECG
- EOG
- Airflow
- Oximeter
What does EEG stand for?
Electroencephalogram.
What EMG stand for?
Electromyogram.
What does ECG stand for?
Electrocardiogram.
What is the most common polysommnogram?
Electroencephalogram
What is measured by an electroencephalogram?
An electroencephalogram measures the electrical activity of the brain.
What does EOG stand for?
Electrooculogram.
What does electromyogram measure?
An electromyogram measures the muscles activity in response to the nerve’s being stimulated.
What is measured by an electrooculogram?
An electrooculogram measures the existing resting electrical potential between the cornea and Bruch’s membrane (eye movements).
What does an electrocardiogram measure?
An electrocardiogram measures the electrical activity of the heart.
What does an oximeter measure?
An oximeter measures the amount of oxygen entering in and out of the lungs.
How is a polysommnogram performed?
A polysommnogram involves a variety of sensors are taped to the body parts to record brain waves, eye movements, muscle tone, body movements, heart rhythm, and breathing patterns overnight.
Why can an electroencephalogram not measure/record the activity of a single neuron?
An EEG cannot register the activity of a single neuron as the electric potential that a single neuron generates is far too small.
How many cycles per second does a single Hertz equal?
One cycle per second.
What is the range of Hertz that an β wave produces?
13 - 30 Hertz.
What is the range in Hertz that an θ wave produces?
3.5 - 7.5 Hertz.
What is the range in Hertz that an α wave produces?
8 - 12 Hertz.
What is the range in Hertz that an δ wave produces?
Less than 4 Hertz.
How were the different stages of sleep determined?
Researchers have examined electrocardiogram’s records of sleep and have detected particular patterns of waveforms activity that equate to different stages of sleep.
What are sleep-spindles?
Sleep-spindles are bursts of neural oscillatory activity that are generated by interplay of the thalamic reticular nucleus and other thalamic nuclei during stage 2. (Bursts are between 12 - 14 Hertz and can occur between two and five times a minute during the first three stages of sleep).
What are K-spindles?
A K-complex is a waveform that may be seen on an electroencephalogram. It occurs during stage 2.
They are spontaneous and have a rate of one cycle per minute (approx).
When do K-complexes appear?
K-complexes commonly appear just before delta waves, which occur during a deep sleep state.
Why do K-complexes appear?
K-complexes are induced by external stimuli, such as unexpected loud noises.
Antony & Paller, 2007; Diekelmann & Born, 2010 (Sleep spindle research).
Sleep spindles appear to play a role in keeping individuals asleep, even in the event of unexpected external stimuli.
They also play a role in memory consolidation.
Fogel & Smith, 2011 (Sleep spindle research).
Research also shows that a high number of sleep spindles are associated with increased intelligence scores.
Ionannides et al, 2007 (K spindles research).
Research has investigated the production and function of spindles and K-complexes in the transition to deeper stages of sleep.
If someone is woken up during stage two sleep, would they believe they were asleep?
No, they would believe they have yet to fall asleep.
Describe how stage three sleep looks like from an EEG recording.
During stage three sleep, slow-wave sleep is dominant, SWS is shown by high amplitude delta activity.
Describe stage four of sleep.
Stage four sleep consists of delta wave activity.
In this stage, brain activity increases to similar levels as when you’re awake and causes vivid dreams. The brain temporarily paralyses major muscles so that we cannot move while dreaming.
This stage is more synchronised.
Describe stage three sleep.
Stage three sleep, a.k.a., deep sleep, it consists of delta wave activity.
In this stage it is harder to wake someone up if they are in this phase. Muscle tone, pulse, and breathing rate decrease in stage three sleep as the body relaxes even further.
Describe stage two sleep.
During stage two sleep, the body enters a more subdued state including a drop in body temperature, muscles become more relaxed, heart rate slows, in addition to slower rate of breathing.
This stage consists of theta, alpha and beta waves.
During this stage (2) sleep spindles and K-complexes are present.
How is slow-wave sleep characterised?
Slow-wave sleep is characterised by delta waves (measured by EEG).
If someone is woken up during slow-wave sleep, would they believe they are asleep?
Yes, they know that they were asleep.
If someone is woken up during slow-wave sleep, would they feel slight confusion?
Yes.
What stage(s) do individuals enter slow-wave (deep) sleep.
Stages three and four.
What happens during REM sleep?
During Rem sleep, individual eyes move rapidly behind their closed eyes, their heart rate increases, as well as their rate of becomes irregular.
Brain activity is also highly active during REM sleep, and the (theta and beta) waves become highly irregular.
What is another name for REM sleep?
Paradoxical sleep.
A single sleep cycle is typically how long (in minutes)?
A typical single sleep cycle is around 90 minutes long.
What type of sleep do dreams occur in?
REM sleep.
As sleep progresses through the night, does the amount of slow-wave sleep increase or decrease?
Decreases as time passes.
As sleep progresses through the night, does the amount of REM sleep increase or decrease?
Increases as time passes.
How long does it take to reach the first cycle of slow-wave sleep (in minutes)?
It takes around 30 minutes to reach the first slow-wave sleep.
How long does the first stage four sleep last (in minutes)?
The first stage four sleep lasts around 45 minutes.
Define alpha activity.
Alpha activity consists of regular, medium-frequency waves, which is smooth electrical activity of 8 - 12 Hz recorded from the brain; generally associated with a state of relaxation.
Define beta activity.
Beta activity consists of irregular, mostly low amplitude waves of 13 - 30 Hz, recorded from the brain; generally associated with a state of arousal.
Define theta activity.
Theta activity consists of 3.5 - 7.5 Hz recorded from the brain; it is generally associated with being awake and REM sleep.
When does desynchronised activity occur?
Desynchronised activity occurs when a person is alert and paying attention to events in the environment or thinking actively.
What is the current sleep scoring system?
The current sleep scoring system identifies stages of wakefulness (stage W), three stages of non-REM sleep (NREM 1, 2, & 3), and one REM sleep stage (stage R).
Define delta activity.
Delta activity is regular, synchronous electrical activity of less than 4 Hz recorded from the brain; occurs during the deepest stages of slow-wave sleep.
Define slow-wave sleep.
Slow-wave sleep is the phase of non-REM sleep marked by the deepest sleep and the highest levels of delta wave activity with brain and muscle activity significantly reduced, loss of response to external stimuli greatest, and with heart rate and respiration at lowest levels.
Define REM sleep.
REM sleep is a a state of sleep that recurs cyclically with non-REM sleep several times during a normal period of sleep, is characterised especially by greatly depressed muscle tone, dreaming with vivid imagery, rapid eye movements, and increased neuronal activity in certain brain regions (such as the pons), and is also know as paradoxical sleep.
Define the disorder fatal familial insomnia.
Fatal famillia insomnia is a inherited disorder charaterised by progressive insomnia.
Define rebound phenomena.
Rebound phenomena is the increase in frequency or intensity of a phenomenon after it has been temporarily supressed;
- For example, the increase in REM sleep seen after a period of REM deprivation.
Define adenosine.
Adenosine is a neuromodulator that is released by neurons engaging in high levels of metabolic activity.
Define locus coeruleus.
The locus coeruleus is a dark coloured group of noadrenergic cell bodies located in the pons near the rostral end of the floor of the fourth ventricle.
What does adenosine play a (primary) role in?
Adenosine is thoerised to play a primary role in the initation of sleep.
What does the locus coeruleus involved in?
The locus coeruleus is involved in arousal and vigilance.
Define the raphe nuclei.
The raphe nucleui is a group of nuclei located in the recticular formation of the medulla, pons, and midbrain, situated along the midline; contain serotongeric neurons.
Define tuberomammillary nucleus (TMN).
The tuberomammillary nucleus is a nucleus in the ventral posterior hypothalamus, just rostral to the mamillary bodies; contains histaminergic neurons.
What is the tuberomammillary nucleus involved in?
The tuberomammillary nucleus is involved in cortical activation and beahvioural arousal.
Define orexin.
Orexin is a peptide, also know as hypocretin, produced by neurons whose cell bodies are located in the hypothalamus.
What would be the result of the destruction of the peptide orexin?
The destruction of orexin would result in the development of the sleep disorder narcolepsy.