Sleep and Consciousness Flashcards
States of Consciousness - Consciousness
- Is awareness of our self and environment.
- Can have different levels of consciousness (diff levels of awareness) and can be natural or be induced by external factors such as drugs or internal such as mental efforts.
- States range from alertness to sleep.
States of Consciousness - Alertness
You’re awake, aware of who you are, what’s going on in the environment, focus your attention, engage in conformation, code info to your memory.
States of Consciousness - Daydreaming
- Feel more relaxed, not as focussed as alertness.
- Can also be light meditation
States of Consciousness - Drowsiness
- Just before falling asleep/after waking up.
- Can also be self-induced in deep meditation.
States of Consciousness - Sleep
Not aware of self or world around you.
Electroencephalograms (EEGs)
- Can measure brainwaves.
- 4 main types:
- Alpha
- Beta
- Delta
- Theta
- Each type oscillates at diff frequency and associated with different type of consciousness.
Beta Waves (12-30Hz)
Associated with awake/concentration.
Alpha Waves (8-13 Hz)
- In daydreaming state. Lower frequency than beta waves.
- Disappear in drowsiness but reappear later in deep sleep.
Theta Waves (4-7Hz)
- Slower/lower frequency than alpha waves.
- Drowsiness/right after you fall asleep/when you are sleeping lightly.
Dealta Waves (0.5-3Hz)
- Slower/lower frequency than theta waves.
- Deep sleep or coma.
Sleep Stages
- Your brain goes through distinct brain patterns during sleep.
- 4 main stages that occur in 90 min cycles.
- First three stages are categorized in non-rapid eye movement sleep (non-REM) – N1, N2, N3
N1 (Stage 1 of Sleep)
Dominated by theta waves.
Hypnagonic Hallucinations (Stage 1 of Sleep)
- Hearing or seeing things that aren’t there
- Example: seeing flash of light, or someone calling your name, doorbell, etc.
Tetris Effect (Stage 1 of Sleep)
- If you play Tetris right before bed, you might see visual images of blocks during sleep.
- Example: Been on a boat all day, you might still feel like you are on water even when on dry land
Hypnic Jerks (Stage 1 of Sleep)
- Muscle twitches you sometimes experience as you fall asleep.
- Feeling of falling.
N2 (Stage 2 of Sleep)
- Deeper stage of sleep.
- People in N2 are harder to awaken.
- We see more theta waves, as well as sleep spindles and K-complexes.
Sleep Spindles (Stage 2 of Sleep)
Sleep spindles in some parts of brain associated with ability to sleep through loud noises.
K-Complexes (Stage 2 of Sleep)
- Supress cortical arousal and keep you asleep.
- Also help sleep-based memory consolidation (some memories are transferred to long term memory during sleep, particularly declarative/explicit memories).
N3 (Stage 3 of Sleep)
- Slow wave sleep.
- Very difficult to awaken.
- Characterized by delta waves.
- Where sleep walking/talking in sleep happens.
- Declarative Memory consolidation.
REM (Rapid-Eye Movement) Stage
- Eyes move rapidly beneath your eyelids but most of your other muscles are paralyzed.
- Most important for memory consolidation.
- Formation of episodic memories.
- Combination of alpha, beta, and dyssynchronous waves, similar to beta waves seen when awake.
- Acronym: BATS-Drink Blood (beta, alpha, theta, ,sleep- spindle/K-complex delta beta)
Order of Sleep Cycle
- N1 -> N2 -> N3 -> N2 -> REM -> N1
- Cycle through these 4-5 times per sleep, each one 90 minutes.
Circadian Rhythms
- Controlled by melatonin, produced in the pineal gland.
- Why you get sleepy in afternoon? They’re our regular body rhythms across 24-hour period.
Prefrontal-Cortex in REM Sleep
- Activity is decreased here. (Part responsible for logic)
Sigmund Freud - Why do Dreams Occur?
Dreams are our unconscious thoughts and desires that need to be interpreted.
Evolutionary Biology - Why do Dreams Occur?
Threat simulation, to prepare for real world.
Sigmund Freud’s Theory of Dreams
Says dreams represent our unconscious feelings/urges/thoughts.
Activation Synthesis Hypothesis (Dreams)
- Brain gets a lot of neural impulses in brainstem, which is sometimes interpreted by the frontal cortex.
- Brainstem = Activation
- Cortex = Synthesis
- Our brain is simply trying to find meaning from random brain activity.
- Therefore dreams might not have meaning.
Disorders: Sleep Deprivation
- Irritability and poorer memory and attention.
- Susceptible to obesity – body makes more cortisol, and the hunger hormone (ghrelin).
- Increase your risk for depression.
Disorders: Insomnia
- Persistent trouble falling asleep or staying asleep.
Disorder: Narcolepsy
- Can’t help themselves from falling asleep.
Disorders: Sleep Apnea
- Stop breathing while sleeping,
- Body realizes you’re not getting enough oxygen, wake up just long enough to gasp for air and fall back asleep without realizing.
- Can happen 100x/night!
- Don’t get enough N3 (Stage 3; slow-wave) sleep.
- Snoring is an indication, or fatigue in morning after full night of sleep.
Disorders: Sleepwalking
- Mostly genetic, occur during N3 (stage 3; slow wave) and are harmless.
- Occur more often in children (partly because they have more N3 stage sleep than adults).
Induced States of Consciousness
- Hypnosis + medication are examples.
- Does not occur naturally.
Hypnotism
- Usually involves getting person to relax and focus on breathing, and they become more susceptible to suggestion in this state – but only if they want to.
- More alpha waves in this stage – an awake but relaxed state.
Meditation
- Training people to self-regulate their attention and awareness.
- Can be guided and focused on something in particular, like breathing, but meditation can also be unfocussed – mind wanders freely.
- More alpha waves than normal relaxation in light meditation.
