Week Nine Flashcards
1
Q
Polysomnography
A
- Used to describe the set of measures used to describe and asses sleep stages.
- At a minimum, three things are needed to assess sleep stages;
○ Electroencephalogram (EEG)= brain waves (brain, electrodes on head).
○ Electrooculogram (EOG)= eye movements (electrodes on eyes, temples).
○ Electromyogram (EMG)= muscle tension (electrodes placed on chest).
- At a minimum, three things are needed to assess sleep stages;
2
Q
EEG
A
- Measures electrical activity in the brain
- When multiple neurons fire action potentials it can be picked up by electrodes placed on the brain.
- Amplitude is how high or low the signal gets
- Frequency is how long or short the wave is.
3
Q
AWAKE
A
- Beta waves are irregular (EEG when awake).
- Muscle tension is high (EMG awake)
- When deciding to go to sleep, EEG shows moderate intensity alpha waves of intermediate frequency.
4
Q
STAGE ONE
A
○ eyes start slow rolling eye movements on EOG
○ EEG changes from alpha waves to theta waves.
○ Muscle tension is moderate
○ Usually stage one is only 10 minutes.
5
Q
STAGE TWO
A
○ EEG shows K-complexes and spindles on the theta waves.
§ Seem to be a sign of your brain compressing external information.
○ No eye movements on EOG.
○ EMG is moderate.
○ Lasts around 20 minutes
6
Q
STAGE THREE
A
○ Slow, large delta waves on EEG. ○ No eye movement on EOG. ○ Moderate EMG. ○ 80 minutes - SLOW WAVE SLEEP
7
Q
STAGE FOUR (REM)
A
○ Sawtooth waves on EEG (looks more like waking waves).
○ Bursts of eye movements
○ Low EMG
○ Stage of dreaming.
8
Q
NREM Sleep
A
- Stages one to three are often known as NREM sleep.
- In NREM sleep, blood pressure comes down, then goes up in REM.
9
Q
Pons
A
- Pons is essential to REM sleep.
- During sleep, pons sends two types of signals
○ First is up to the thalamus and the cortex, an activating signal. This is associated with dreams
○ Second is towards the spinal cord and is a deactivating signal.
- During sleep, pons sends two types of signals
10
Q
dreams
A
- We usually remember dreams from our last REM cycle.
- More likely to remember longer dreams, those with emotional intensity and ones towards the end of the night.
- REM dreams are weird and unconventional.
- NREM dreams are more similar to everyday life, can be thoughts etc.
11
Q
sleep is…
A
homeostatic and circadian
12
Q
homeostatic
A
- Homeostatic refers to the fact that the longer we are awake the more we need sleep. Also known as Process S.
- Adenosine is a neurotransmitter that is increased the longer we are awake.
- Caffeine blocks adenosine receptors.
13
Q
circadian
A
- Without external input, out body still revolves around a 24 hour cycle.
- Circadian rhythms are behavioural, biochemical and physiological fluctuations occurring over a 24 hour period.
○ Sleep/wake cycle is influenced by internal clock.
○ Suprachiasmatic nucleus (SCN) located in the hypothalamus and contains our internal clock.
○ Our internal clock is generally longer than 24 hours
○ We have mechanisms for synchronising this clock with the outside world. - Light is our primary zeitgeber (time giver).
- Retinohypothalamic tract deals with light.
- Circadian rhythms are behavioural, biochemical and physiological fluctuations occurring over a 24 hour period.
14
Q
jetlag
A
- Occurs when crossing a number of time zones
- Results in a mismatch between our internal clock and our external day.
- Jetlag is generally worse when travelling east as you are trying to shift your sleep period earlier.
15
Q
sleep deprivation
A
- More likely to fall asleep
- PDT, press a button when the red dot appears on the screen.
- In sleep deprivation we see a slowed response time, a narrowing of attention and increased error.
- Difficulty thinking flexibly and with short term memory.
- Mood and emotion is also affected.
- People become more risky when sleep deprived.
- There is a large variability in response.
