Sleep and consciousness Flashcards
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.
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.
Daydreaming-
feel more relaxed, not as focussed as alertness. Can also be light meditation (self-induced)
Drowsiness
just before falling asleep/after waking up. Can also be self-induced in deep meditation.
Sleep
not aware of self or world around you.
Electroencephalograms (EEGs) can measure
brainwaves
Beta
(12-30Hz) – associated with awake/concentration. If you are alert
for too long, beta levels get high and you experience increased stress,
anxiety, restlessness- constant awakened alertness.
Alpha
(8-13 Hz) – in daydreaming state. Lower frequency than beta
waves. Disappear in drowsiness but reappear later in deep sleep
Theta
(4-7 Hz) slower/lower frequency than alpha waves.Drowsiness/right after you fall asleep/when you are sleeping lightly.
Delta
(0.5-3 Hz) – Slower/lower frequency than theta waves. Deep sleep
or coma.
Your brain goes through distinct brain patterns during sleep. 4 main stages occur in
90 min cycles
First three stages of sleep stages are categorized in
non-rapid eye movement sleep (non-REM) – N1, N2, N3
N1
Dominated by theta waves.
Strange sensations – hypnagogic hallucinations, hearing or seeing things that aren’t their
Or the Tetris effect – if you play Tetris right before bed, you might see visual images of blocks during sleep.
Also a feeling of falling – hypnic jerks- muscle twitches you sometimes experience as you fall asleep.
N2
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
are a burst of rapid brain activity. Some researchers think that sleep spindles help inhibit certain perceptions so we maintain a tranquil state during sleep. Sleep spindles in some parts of brain associated with ability to sleep through loud noises.
K-complexes
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). Even though they occur naturally, you can also make them occur by gently touching someone sleeping. “that touch was not threatening, stay asleep brain”
N3 (Stage 3)
slow wave sleep. Very difficult to awaken. Characterized by delta waves. Where sleep walking/talking in sleep happens. Declarative Memory consolidation. “regular breathing and regular slow brain waves”
REM (rapid-eye movement) stage
Eyes move rapidly beneath your eyelids but most of your other muscles are paralyzed. Most dreaming occurs during REM sleep, so paralyzation inhibits actions.
Most important for memory consolidation. Formation of episodic memories. Combination of alpha, beta, and dyssynchronous waves, similar to beta waves seen when awake.
order of sleep order?
N1 -> N2 -> N3 -> N2 -> REMàN1
Circadian Rhythms
why you get sleepy in afternoon. They’re our regular body rhythms across 24-hour period. Controlled by melatonin, produced in the pineal gland.
Activity in prefrontal cortex during REM sleep is
decreased
Sigmund Freud theory on dream
Dreams are our unconscious thoughts and desires that need to be interpreted. Little scientific support
Evolutionary biology theory on dreams
o Threat simulation, to prepare for real world.
o Problem solving
o No purpose
Manifest content.
What happens? Literal meaning.
Latent content.
What is hidden meaning?
Activation Synthesis Hypothesis
§ Brain gets a lot of neural impulses in the brainstem, which is sometimes
interpreted by the frontal cortex.
§ Brainstem = activation, and cortex = synthesis.
§ Our brain is simply trying to find meaning from random brain activity.
Therefore dreams might not have meaning.
insomnia
persistent trouble falling asleep or staying asleep
narcolepsy
can’t help themselves from falling asleep
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
Sleepwalking/sleep talking
mostly genetic, occur during N3 (stage 3; slow wave) and
are harmles
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. Morealpha 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.
o More alpha waves than normal relaxation in light meditation.