Sleep Flashcards
What is EEG used to measure?
Used to measure brain activity
Where are EEG discs placed and to measure what?
They’re placed directly on scalp and measure changes in activity of the cells of the brain
What does EEG measure?
EEG measures the combined activity of a large number of similarly oriented neurons
What does an EEG require?
An EEG requires synchronous activity across groups of cells
What does the amplitude of an EEG signal depend on?
Amplitude of an EEG signal depends upon how synchronous the activity of the neuron is
How is a large surface signal generated in an EEG?
When a group of ells are excited, the tiny cells sum to generate a large surface signal
Why is timing important in an EEG?
Timing is everything because the same amount of excitation can occur, but at irregular intervals resulting in a small summed signal
What do EEG rhythms correlate with?
EEG rhythms correlate with states of behaviors
What are EEG rhythms categorised by?
EEG rhythms are categorised by their frequency range:
- Awake with mental activity(Beta 14-30Hz)
- Awake and resting(Alpha 8-13Hz)
- Sleeping(Theta 4-7Hz)
- Deep sleep(Delta <3.5Hz)
What are the 2 theories of the generation of rhythms?
- Pacemaker
- Mutual excitation/inhibition
What is the hypothesis for slow frequency, high amplitude rhythms during sleep?
The thalamus acts as a gatekeeper for information transmission
What is the hypothesis for fast frequency, low amplitude rhythms during wakefulness?
The brain is attention grabbing to bind together regions needed for task execution
What is sleep?
Sleep is a reversible state of reduced responsiveness to and interaction with the environment
What are the functional states of the brain?
- Awake state
- Non-REM sleep
- REM sleep
What is the EEG like in an awake state?
- Low amplitude
- High frequency
What is the sensation like in the awake state?
- Vivid
- Externally generated
What is movement like in the awake state?
- Continuous
- Voluntary
What is REM like in the awake state?
Often
What is the EEG like in non-REM sleep?
- High amplitude
- Low frequency
What is the sensation like in non-REM sleep?
- Dull
- Absent
What is the thought process like in non-REM sleep?
- Logical
- Repetitive
What is movement like in non-REM sleep?
- Occasional
- Involuntary
What is REM like in non-ERM sleep?
Rare
What are the conditions like in non-REM sleep?
- Decrease in temperature
- Decrease in heart rate
- Decrease in breathing
- Decrease in brain energy consumption
What is the EEG like in REM sleep?
- Low amplitude
- High frequency
What is the sensation like in REM sleep?
- Vivid
- Internally generated
What is the thought process like in REM sleep?
- Vivid
- Illogical
- Bizarre
What is movement like in REM sleep?
Muscle paralysis
-Brain command movement but not carried out
What is REM like in REM sleep?
Often
What does each night begin with in the sleep cycle?
-Each night begins with a period of non-REM sleep
What are the neural mechanisms in wakefulness?
-Large amount of brainstem activity
-Have many neurotransmitters
-These increase excitatory activity to decrease
synchronous firing
What are the neural mechanisms in falling asleep?
- Reduction in brainstem activity
- Thalamus is the conductor of theta and delta waves
What are examples of sleep promoting factors?
- Adenosine
- Nitric oxide
- Inflammatory factors
- Melatonin
What happens to adenosine levels at the end of the day?
Adenosine levels increase at the end of the day
What decreases when adenosine receptors are activated?
Adenosine receptor activation decrease heart rate, respiratory rate and smooth muscle tone
What does nitric oxide do?
- Reduces small muscle tone
- Stimulates adenosine release
What is the circadian rhythm?
Is the biological clocks
What are zeitgebers?
Zeitgebers are environmental time cues
- Temperature
- Noises
Where is the suprachiasmatic nucleus (SCN) located?
Located between the optic chiasm at the base of the hypothalamus
What is the SCN important in providing?
Important in providing us with our sleep wake circadian rhythm
Why is the SCN needed?
SCN needed to regulate sleep in the absence of zeitgebers
Steps involved in the activation of melanopsin receptors?
- Activation of melanopsin receptors in the eye transmit this activation to the SCN
- The SCN inhibits the pineal gland
- Pineal gland is important in the production of melatonin
