Unit 4 AOS 1 Flashcards
Sleep
define sleep
Sleep is a regular and naturally occurring altered state of consciousness that involves a loss of awareness and disengagement with internal and external stimuli.
what can sleep be considered as?
Sleep can also be considered a psychological construct.
what is sleep governed by?
We sleep every day, governed by our circadian rhythm (biological clock)
define naturally occurring
occurs without the need of aids
define altered state of consciousness
a state where we have lowered awareness/alertness and involves distortions
define psychological construct
A psychological construct refers to psychological phenomena that we believe exist but cannot see or touch. It’s also a construct that can be difficult to overtly measure.
what awareness do you have when your asleep?
When you are asleep you are often have very little awareness of your surroundings, you have lowered self control and perception
what consciousness can sleep be described as?
Sleep can be described as a regular and naturally occurring altered state of consciousness.
define consciousness
Consciousness is the level of awareness an individual has over their thoughts, feelings, perceptions and existence.
what range is consciousness on?
Consciousness ranges along a continuum
what are the boundaries of consciousness?
- Consciousness is not an “all or nothing” experience, there are variations in the extent or degree of awareness we experience at different times
- There are no distinct boundaries between one state and another
what are the states of consciousness?
- altered state of consciousness
- normal waking consciousness
examples of altered state of consciousness?
- coma
- sleep
- anaesthetised
- alcohol-induced
- meditation
- drowsy
- day dreaming
examples of normal waking consciousness?
- relaxed state
- focussed attention
define normal waking consciousness
Refers to the states of consciousness associated with being awake and aware of our thoughts, memories, feelings and the sensations we are experiencing from the outside world
features of normal waking consciousness?
- Our perceptions and thoughts continue to be organized and clear, we perceive the world as real and maintain a sense of time and place
- Its not one single state- but rather includes all states of consciousness that involve
heightened awareness
how long are we in normal waking consciousness?
2/3 of our day is spent in NWC
define altered state of consciousness
Any state of consciousness that is distinctly different from normal waking consciousness, characterised by lowered levels of awareness
what are the sub categories of altered state of consciousness?
- naturally occurring altered state of consciousness
- induced altered state of consciousness
define naturally occurring altered state of consciousness
a type of altered state of consciousness that occurs without intervention
examples of naturally occurring altered state of consciousness?
- sleep
- day dreaming
define induced altered state of consciousness
a types of altered state of consciousness that occurs due to purposeful action or aid
examples of induced occurring altered state of consciousness?
- meditation
- hypnosis
- influence of alcohol and/or drugs
what are the characteristics of sleep?
- A reduced ability to control behaviour
- Reduction in the control we have over thoughts, (e.g. dreams)
- Lowered perception to pain
- Less accurate understanding of the passage of time
what is sleep made up of?
Sleep is made up of both NREM and REM stages
what is Rapid eye movement (REM)?
- Characterised by rapid eye movement, high levels of brain activity and low levels of physical activity
- Low levels of somatic nervous system activity – “paradoxical sleep”
what is Non-rapid eye movement (NREM)?
- Characterised by lack of rapid eye movement
- Is subdivided into three different stages
what is a sleep episode?
the full duration of time spent asleep
what is a sleep episode made up of?
Made up of multiple repeated sleep cycles of REM and NREM – sleep cycles which last approximately 90 minutes
what is a sleep cycle?
A sleep cycle is an approximately 90-minute-period that repeats during a sleep episode in which an individual progresses through stages of REM and NREM sleep.
What is the purpose of sleep?
- survival
- physical recovery
- mental recovery
characteristics of REM sleep?
- During REM sleep, the sleeper is virtually paralysed; most muscle movement is not possible (muscle paralysis)
- Involves sudden onsets of rapid eye-movement beneath closed eyelids
- Dreaming tends to occur during REM
- The sleeper frequently recalls dreams when woken during REM sleep
- REM is a light stage of sleep; Sleepers can be woken fairly easily from this stage
- During REM, the brain is highly active and is it thought this stage replenishes the brain
what happens to the amount of REM sleep in a sleep episode?
The amount of time spent in REM increases as the sleep episode progresses, with the largest amount of REM sleep occurring immediately before waking (can last up to an hour in the last cycle)
how much of a sleep episode is REM?
REM sleep makes up approx 20-25% of a sleep episode for most age groups
what is NREM divided into?
NREM sleep is subdivided into 3 different stages (NREM1, NREM 2, NREM 3)
what does REM stand for?
RAPID EYE MOVEMENT
what does NREM stand for?
NON RAPID EYE MOVEMENT
characteristics of NREM sleep?
- Muscle movement is possible for the sleeper during NREM sleep
- The sleeper does not frequently recall dreams when woken during NREM
- NREM is believed to be important for replenishing the body
what happens to the amount of NREM sleep in a sleep episode?
The amount of time spent in NREM sleep is highest during the first half of a sleep episode
how much of a sleep episode is NREM?
NREM sleep makes up approximately 75-80% of a sleep episode
what type of sleep is NREM1 and NREM2?
NREM1 and NREM2 are light sleep and the sleeper may not realise that they have been sleeping if woken during these stages
what type of sleep is NREM3?
NREM3 is deep sleep and the sleeper is likely to feel drowsy and disoriented if woken during these stages
Differences (REM vs. NREM)?
- REM duration becomes longer over the later sleep cycles, whereas NREM becomes shorter.
- NREM stages 3 are generally evident in first couple of cycles, whereas REM occurs throughout the night.
- Overall time spent in NREM is greater than REM.
- NREM sleep has 3 stages and REM has one
define hypnogram?
sleep graph that tracks the proportion of time spent in each stage of sleep
what are the lightest and deepest sleep stages in NREM?
Each successive stage of NREM sleep is indicative of a deeper sleep, with stage 1 being the lightest and stage 3 as the deepest
characteristics of Stage 1 NREM?
- During the transition from being awake to being asleep, we enter a relaxed state known as a hypnogogic state.
- We may experience hallucinatory images, such as flashes of light and Hypnic jerks (involuntary muscle twitches that cause us to jolt)
- Stage 1 is brief, lasting 5-10 minutes. It’s very light and we are easily awakened. People woken during Stage 1 will often report that they weren’t actually asleep.
- Overall, slowdown in brain wave patterns (alpha, then replaced by theta waves)
characteristics of Stage 2 NREM?
- Generally considered the point at which true sleep starts. Stage 2 lasts about 10-25 minutes in our first sleep cycle (lengthens with each successive cycle), and we are still easy woken.
- As we slip deeper into Stage 2, we become more relaxed – breathing, heart rate and blood pressure decrease and we are unlikely to respond to anything except strong/loud stimuli
- Predominantly theta waves
characteristics of Stage 3 NREM?
- Deepest stage of sleep (also known as slow wave sleep)
- We become less responsive to external stimuli
- Our muscles are completely relaxed and we barely move. Delta waves dominate.
- More difficult to awaken - if awoken, we feel very groggy and disorientated.
- Our eyes do not move and we become even more relaxed.
- Often the stage where sleep walking and sleep talking occur
- Decreases in length as cycles progress through the night. In the latter half of a sleep episode, there may no stage 3 sleep at all.
eyes in REM vs NREM?
REM - fast, jerky
NREM - slow, minimal
brainwaves in REM vs NREM?
REM - beta
NREM - delta
body in REM vs NREM?
REM - Paralysis
NREM - Movement possible
Physiological Responses in REM vs NREM?
REM - increases
NREM - decreases
Presences of Dreams in REM vs NREM?
REM - yes
NREM - no
Timing in Night in REM vs NREM?
REM - Increases across the night 2min - 1 hour
NREM - Start of the sleep cycle
% of Sleep in REM vs NREM?
REM - ~20%
NREM - ~80%
Necessary for, REM vs NREM?
REM - mind
NREM - body
what are the ways we can measure sleep?
- EEG
- EOG
- EMG
- SLEEP DIARIES
- VIDEO MONITORING
Measurement of physiological responses in sleep?
- EEG
- EOG
- EMG
what do these ways of measuring physiological responses enable and provide?
- Enable researchers to obtain data on bodily changes during different SOC.
- Provide valuable info on levels of awareness that occur in different states
what do the three common physiological measures in sleep include changes in?
brain wave patterns, muscle activity & eye movements
define Electroencephalograph (EEG)
An EEG, is a device that Detects, Amplifies and Records Electrical activity of the brain (in the form of brainwaves).
how is an EEG achieved?
Achieved by placing electrodes on the scalp, which detect signals from neurons in the brain
how is an EEG shown?
The brain waves recorded are displayed as a graph on a computer
how can an EEG measure sleep?
Different states of consciousness cause changes in brain-wave patterns
define brain waves
a pattern of electrical activity in the brain caused by neurons communicating
what do brain waves provide?
Provide an indication of a person’s level of alertness (ie. state of consciousness)
how are brain waves read and represented?
- They are visually represented as wavy lines
- When reading an EEG recording, both the frequency and amplitude are recorded
what is frequency with regards to brain waves?
Frequency (rate) - how many brainwaves there are per second. Ie. How close the waves are to one another. The closer = the higher frequency
what is amplitude with regards to brain waves?
Amplitude (height) - the intensity of the electric current in the brain. The height of peaks and dips in the waves. The higher the peak = the higher the amplitude.
what do high frequency and low amplitude waves equal?
high levels of alertness
what do low frequency and high amplitude waves equal?
lower levels of alertness
what is an EEG likely to show in REM sleep?
higher frequency and lower amplitude brain waves in REM sleep - beta like brain waves
what is an EEG likely to show in NREM sleep stage 1 sleep?
high frequency and low amplitude in NREM sleep stage 1 (transitioning from wakefulness to sleep), but lower frequency and higher amplitude than normal-waking consciousness - alpha like brain waves
what is an EEG likely to show in NREM sleep stage 2 sleep?
medium frequency and medium amplitude in NREM sleep stage 2 (light sleep) - theta like brain waves
what is an EEG likely to show in NREM sleep stage 3 sleep?
lower frequency and higher amplitude in NREM sleep stage 3 (deep sleep) - delta like brain waves
what is a strength of EEG’s?
useful for sleep studies or diagnoses of patients with brain damage or a neurological or mental disorder.
what is a limitation of EEG’s?
Limitation of EEGs as a measure of sleep is that it measures neural activity underneath a thick and hard skull and thus is not entirely precise. It also does not pinpoint or identify functional or dysfunctional areas of the brain as well as neuroimaging techniques, such as an fMRI
what are the types of brain waves in sleep?
- Beta
- Alpha
- Theta
- Delta
what can an EEG show that demonstrates a sleeper is truly asleep?
During NREM sleep stage 2, the sleeper is considered ‘truly asleep’. EEG readings can reflect this by showing ‘sleep spindles’, which are brief bursts of high frequency waves which sleep researchers identify as the point where a sleeper is truly asleep.
what are beta waves frequency and amplitude?
- high frequency
- low amplitude
what are alpha waves frequency and amplitude?
- high frequency (but lower than beta)
- low amplitude (but higher than beta)
what are theta waves frequency and amplitude?
- medium frequency
- medium-high amplitude
what are delta waves frequency and amplitude?
- low frequency
- high amplitude
define electromyograph (EMG)
The EMG Detects, Amplifies and Records Electrical of the body’s muscles.
what does an EMG record?
EMG recordings indicate changes in muscle activity (movement) and muscle tone (tension).
how is an EMG obtained?
- Obtained by attaching electrodes to the skin above muscles.
- Sometimes the activity in facial muscles is recorded, leg muscles, muscles on the torso or a combination of these
How does an EMG indicate changes in SOC?
- E.g. when falling asleep, our muscles progressively relax (decrease in muscle tone)
- Generally, EMG measures indicate that the higher level of muscular activity and tone, the more alert we tend to be
define Electro-oculargraph (EOG)
The EOG Detects, Amplifies and Records Electrical of the muscles surrounding the eyes.
what does an EOG indicate?
Little to no activity of these muscles would indicate low levels of awareness
what is an EOG most commonly used for?
Most commonly used to measure changes in eye movements associated with different stages of sleep and dreaming
why is an EOG valuable?
Extremely valuable in differentiating between two different stages of sleep Rapid Eye Movement (REM) sleep and non-rapid eye-movement (NREM).
what is DARE?
detects, amplifies and records the electrical activity of…
what does an ECG do?
The ECG detects, amplifies and records the electrical activity of the heart (Electrocardiogram)
what are the subjective reporting of consciousness?
- Sleep diaries
- Video Monitoring
what does subjective reporting involve?
Subjective reporting involves the use of self-reports — the participant’s written or spoken responses to questions, or statements by the researcher. (qualitative data)
what are sleep diaries?
Sleep diaries are the most widely used method - they are a record of individual descriptions of amount, nature and quality of sleep
what are sleep diaries used in conduction with?
Often used in conjunction with physiological measures such as EEG and EMG