Week 3 - Sleep Flashcards
1
Q
Describe the human nervous system…
A
- Brain is made up of neurons and glial cells that process information
- Spinal cord extends from the brain made up of neurons inside the back bone
- The spinal cord widens to become the brain stem, the thalamus located in the centre of the head
- Brain is bilaterally symmetrical, with left and right hemispheres
- Pace makes synchronize the electro chemical activity (Steriade, 2000)
2
Q
What does thalamus and the prefrontal cortex do?
A
- Thalamus
- Deciphers senses travelling through the brain - Prefrontal Cortex
- Management center, organizes thoughts, decision centre
3
Q
Describe axons and communication…
A
- Messages travels from 1 neurons to the next
1. Dendrites receive the neurotransmitter
2. Travel through the axon where there are changes in electrical potentials
3. Messages are sent out through the terminal buttons
4
Q
How did we use to think of sleep? How did Lilly changes this?
A
- We used to think sleep was considered to be a result of a dormant brain and a lack of senses
- Lilly discovered that the removal on sensory stimulation did not cause sleep
- Not all activities excitatory
5
Q
What is a polysomnography?
A
- When voltage changes can be measured with electrodes attached on the scalp
- Measurement taken from layer 4 of the brain
6
Q
What are the tools used in brain activity?
A
- Electroencephalograph (EEG)
- Measures brain waves associated with sleep - Electrooculograph (EOG)
- Used to detect eye movements - Electomyograph (EMG)
- Measures muscle tension with electrodes placed on chain
(Carskadon, 2000)
7
Q
Describe the wave of an EEG…
A
- Beta waves; frequency greater than 13 cycles per second
- Alpha waves; 8-13 cps
- Thata waves; 4-7 cps
- Delta waves; less than 4 cps
** Shorter rapid waves = less amplitude
** Longer waves, low frequency = greater amplitude - Ex. Delta waves can exceed amplitudes of 200 microvolts
(Rechtschaffen and Kale, 1968)
8
Q
What are the other devices that can be used to measure physiological events in sleep?
A
- Heart rate
- Oxygen content of blood
- Breathing difficulties
(Kryger, 2000) - Penial circumference (Ware, 2000)
- Motor movements (Spielman, Yang and Glovinsky, 2000)
** Simultaneous recording is called a polysomnography
9
Q
Describe the waking state of the EEG…
A
- There is beta activity, with some alpha activity and occasional theta activity
- EOG shows rapid eye movements and blinks
- EMO shows high levels of muscle activity
(Aldrich, 1999) - For 85-90% of people, relaxing and closing their eyes results in the occurrence of alpha rhythm
- On set of sleep is indicated by some alpha and predominance of theta
10
Q
Describe Stage 1 of sleep… (NREM)
A
Stage 1
- Relatively low voltage mix frequency EEG
- Vertex shaped waves with sharp negative peaks reaching 200 microvolts, can occur in isolation or groups
- Slow eye movements usually proceeding the beginning of sleep
- No discrete change in muscle tension
- Lasts 1-7 minutes
11
Q
Describe Stage 2 of sleep…. (NREM)
A
- Presences of K complexes and sleep spindles with mixed frequencies mostly in theta range
- K complex = waveform lasting for at least .5 seconds that consists of a sharp negative components of several hundred microvolts immediately followed by a positive slow wave
- 1-3 K complexes per minute
- Sleep spindle = a brain wave of 12-14 cos in frequency lasting .5 - 1.5 seconds -3-8 spindles per minute
- Slow eye movements may infrequently
- low amplitude muscle movements
- as stage 2 deepens, high amp delta waves become frequent
- lasts 10-25 minutes
12
Q
Describe stage 3 and 4 of sleep… (NREM)
A
- Stage 3: Delta waves slower than 2cps of at least 75 microvolts that occupy 20% of the sleep record. lasts few minutes
- Stage 4: if these slow, high amp delta waves occupy more than 50% of the sleep, lasts 20-40 minutes
- K complexes and sleep spindles may happen here
- Alpha-delta sleep (large amp alpha rhythms that are 1-2 cps slower than the waking alpha
- both are referred to as slow-wave sleep = no eye movements and low muscle tension
13
Q
Describe REM sleep
A
- after 80 minutes from onset of sleep
- Delta activity declines with low voltage, mixed frequency rhythm that occurs resembling stage 1 but with no vertex shaped waves
- Alpha activity 1-2 cps slower than waking state and sawtooth waves of 2-6 cps lasting 1-5 seconds occurring intermittently
- Eye movements are rapid & jerky
- brief episodes of facial muscle activity
- Phasic REM sleep =muscle twitching with bursts of eye movements
- tonic REM = no eye movements or muscle twitches
- muscle atonia = suppression of skeletal muscle, short-lived
- Penile erections
- highly activated brain in a paralyzed body
- paradoxical sleep
- first rem lasts 15 minutes
14
Q
Describe the patterns of sleep stages
A
- NREM and REM is repeated
- first cycle is 70-100 minutes, second cycle is 90-120 minutes (total of 4-6 cycles) - duration increases with every cycle avg of 22 minutes long
- Slow wave sleep decreases in the second cycle - eventually body goes into 2 REM cycles - skips 3-4)
15
Q
Define sleep latency, sleep efficiency & continuity
A
latency - the time it takes to fall asleep
efficiency - the ratio of actual time spent asleep to time spent in bed
continuity - the overall balance of sleep and wakefulness during a night of sleep
