Consciousness and Sleep
Introduced| English | Meaning |
|---|---|
| Consciousness/ˈkɒnʃəsnəs/ | Awareness of internal experiences and the surrounding environment. |
| circadian rhythm/sɜːˈkeɪdɪən ˈrɪðəm/ | A biological cycle that repeats approximately every 24 hours, such as the sleep-wake cycle. |
| Jet lag/dʒet læɡ/ | Temporary disruption caused when travel across time zones leaves the body's internal clock out of step with local time. |
| shift work/ʃɪft wɜːk/ | shift work |
| stages of sleep/ˈsteɪdʒɪz ɒv sliːp/ | stages of sleep |
| REM sleep/rem sliːp/ | A phase of sleep characterised by rapid eye movements, active brain patterns and greatly reduced muscle tone. |
| Memory consolidation/ˈmeməri kənˌsɒlɪˈdeɪʃn/ | Memory consolidation |
| restoration/ˌrestəˈreɪʃn/ | The idea that sleep repairs the body and replenishes energy. |
| activation-synthesis/ˌæktɪˈveɪʃn ˈsɪnθəsɪs/ | activation-synthesis |
| consolidation theory/kənˌsɒlɪˈdeɪʃn ˈθɪəri/ | An account of sleep and dreaming in which the sleeping brain helps stabilise and organise newly formed memories. |
| sleep disorders/sliːp dɪˈsɔːdəz/ | sleep disorders |
Awareness comes in degrees
- You are not simply awake or asleep — you can be alert, drowsy, absorbed, or barely aware.
- Consciousness 意识 is defined by these varying levels of awareness of thoughts, feelings and events.
- Sleep is the clearest case of awareness changing on a schedule.
A roughly 24-hour clock
- The sleep/wake cycle is a circadian rhythm 昼夜节律, about 24 hours long in humans.
- Jet lag 时差反应 and shift work 轮班工作 disrupt it, because the clock cannot move as fast as the schedule does.
- The effects show up as poor sleep, poor attention and low mood.
A participant wired for polysomnography- this is what measuring sleep stages actually looks like
The roughly 24-hour sleep/wake cycle is called a ____ rhythm.
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The circadian rhythm runs about 24 hours and is disrupted by jet lag and shift work.
Stages, identified by their brain waves
- The stages of sleep 睡眠阶段 are identified by their specific EEG patterns.
- That is the operational definition: a stage is a pattern of electrical activity, not a feeling.
- REM sleep 快速眼动睡眠 has its own distinctive pattern and is when most vivid dreaming occurs.
Ride one sleep cycle
Sleep is a repeating cycle, not a slide into ever-deeper sleep — and REM lengthens across the night.
The stages of sleep are identified by...
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A stage is defined by a pattern of electrical activity, measured by EEG.
Do not describe a sleep stage by how deeply asleep someone feels. The CED defines the stages by their EEG patterns, and an answer that uses subjective depth instead of the measure has not used the course's definition.
Select all the theories the CED gives for why sleep occurs.
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Activation-synthesis explains dreams, not why sleep occurs; place theory is about pitch.
Match each theory to what it explains.
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Two of these answer "why" and one answers "when" — keep the questions apart.
Why we sleep, and why we dream
- Memory consolidation 记忆巩固 and restoration 恢复 are the current theories of why sleep occurs.
- For dreams, the CED names activation-synthesis 激活—合成 theory and consolidation theory 巩固理论.
- Both dream theories treat dreaming as a by-product of what the sleeping brain is doing anyway.
Sleep disruption is only a symptom of daytime problems, never a cause of them.
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Poor sleep causes problems with attention, mood, learning and physical health.
When sleep goes wrong
- Many sleep disorders 睡眠障碍 interrupt healthy sleep, and their effects on waking behaviour vary.
- Sleep disruption affects attention, mood, learning and physical health.
- The examinable point is that poor sleep is a cause of daytime problems, not only a symptom of them.
A nurse moves from day shifts to night shifts. Her circadian rhythm still runs on the old schedule, so she lies awake at 3 a.m. and is sleepy at 3 p.m. Nothing is wrong with her sleep system — the clock simply has not moved as fast as her timetable.
Consciousness varies in level. The sleep/wake cycle is a circadian rhythm of about 24 hours, disrupted by jet lag and shift work. Stages of sleep are defined by EEG patterns; consolidation and restoration explain why we sleep; activation-synthesis and consolidation theory explain dreams.
Write from a body clock at 4 a.m.
- A flight moves 6 time zones east. At 10 a.m. local time the traveller's body clock still reads 4 a.m.
- Name the disruption.
After a flight of 6 time zones east, local time is 10 a.m. and the body clock reads 4 a.m. What is disrupted?
10 minus 6 is 4. The clock is slow to follow the new light schedule.
What is the traveller experiencing?
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The 6-hour mismatch is jet lag. The rhythm itself is intact.