What is Sleep? Flashcards
Consciousness
Consciousness is the awareness of our own internal mental processes, including thoughts, feelings, sensations and perceptions, and our awareness of the external world around us.
It is unique, subjective, and constantly changing, and a psychological construct.
It can be divided into 2 distinct categories: Normal Waking Consciousness (NWC) and Altered States of Consciousness (ASC)
A state of consciousness is your awareness of stimuli (internal and external)
Normal Waking Consciousness (NWC)
Normal Waking Consciousness is a state associated with being aware of our internal and external environments.
It is a state where we spend most of our lives.
It is a state of clear, organized alertness to both internal and external stimuli
Where we perceive events / time / places, etc. as real and meaningful.
Characteristics of Normal Waking Consciousness
- Awareness: of our internal and external environment is high and can focus our attention on what we want
- Content Limitations: are controlled; meaning we control what we think about
- Controlled and Automatic Processes: we can complete all types of tasks
- Emotional Awareness: where we have control of our emotions, and they are appropriate
- Perception and Cognition: are accurate; we can think clearly and are aware of our sensations
- Time Orientation: is normal; we can understand the passing of time
- Self Control: of our actions is high
Altered States of Consciousness (ASC)
Altered states of consciousness are any state of consciousness that differs in awareness from NWC.
This is where, generally, people experience a reduced awareness of internal and/or external stimuli
Our emotions and perceptions of events/time/places/emotions, etc. Can be distinctly different from NWC
This often occurs with our perception of the intensity or quality of these things.
Can occur naturally (eg. Dreams / sleep, etc.) Or be induced (eg. Drinking alcohol, etc.)
Characteristics of Altered States of Consciousness
-Awareness: of our internal and external environment is lowered, and we have difficult concentrating
- Content Limitations: are not controlled; multiple thoughts come into our mind
- Emotional Awareness: where we have less control of our emotions, and they can be inappropriate
- Perception and Cognition: can be inaccurate; we have difficulty thinking clearly, and have heightened or duller sensations
- Time Orientation: is skewed; time passes slower or faster
- Self control: of our actions is lowered
Naturally Occurring ASC
Sleep is a naturally occurring and reversible ASC, characterized by a reduction in awareness and responsiveness to external surroundings.
They are unique brain wave activities that occur during sleep.
It is vital for our ongoing health and wellbeing and helps to support and protect our mental/physical health.
It involves dynamic changes to our psychological and physiological experiences.
It is measurable using things such as EEG’s, EOG’s, sleep diaries, etc.
It is organized into 2 distinct categories: REM & NREM
These are experienced through the night in roughly 90-minute cycles.
Induced ASC
NREM and REM (Sleep as a Psychological Construct)
Non- Rapid Eye Movement Sleep:
- Consists of three stages
Rapid Eye Movement Sleep
- Both experienced by all people but in varying proportions throughout the lifespan
- Have different restorative purposes
Measurement of Sleep
Various techniques can be used to study sleep which can be done either objectively or subjectively.
Used to understand:
- The physiological changes experienced by people during sleep
- How sleep changes across the lifespan
- The symptoms and treatment options for people suffering from sleep disturbances
These are often completed in sleep labs (a controlled environment)
- Allows for more precision when monitoring sleep patterns
- Allows researchers to observe sleep over longer periods
EEG (Measurements of Sleep/ASC)
Electroencephalograph
A non-invasive device used to detect, amplify and record the electrical activity in the brain in the form of brainwave patterns.
Uses electrodes placed on the scalp
Can be used during sleep or wakefulness
Measures brainwaves (made from the communication occurring between the billions of neurons in our brain)
Brainwaves are understood by looking at frequency and amplitude of the pattern
Difference combinations of frequency and amplitude indicate the different stages of sleep.
EOG (Measurements of Sleep/ASC)
Electro-oculograph
A non-invasive device used to detect, amplify and record the electrical activity of the muscles around the eyes.
Uses electrodes placed around the eye socket/eyebrows
Can be used during sleep or wakefulness
Measures muscle movement around the eyes, as different speeds/amounts of movement indicate different stages of sleep.
EMG (Measurements of Sleep/ASC)
Electromyograph
A non-invasive device used to detect, amplify & record the electrical activity in the skeletal muscles
Uses electrodes placed on skin around larger muscle groups (e.g. arms / legs / jaw, etc.)
Can be used during sleep or wakefulness
Measures muscle tension
Different amounts of muscle tension indicate different stages of sleep (eg. NREM stage 3 will feature low levels of muscle tension.)
Sleep Diaries (Measurements of Sleep/ASC)
Sleeps diaries are a subjective, self-report tool used by a person to track their own sleep and wake patterns that collect information that the EEG / EOG / EMG can’t collect.
Can gather qualitative and quantitative data
An inexpensive subjective measure, as it relies on people keeping their own records of personal experiences
Gives insight into thoughts / emotions
Need to be used in conjunction with objective / scientific measures for accuracy
Can be fallible if people forget things / don’t write them down, etc.
Video Monitoring (Measurements of Sleep/ASC)
Video monitoring is used to collect qualitative visual and audio information about a person’s sleep.
It involves using cameras to record peoples’ activities whilst sleeping
useful for seeing observable sleep disturbances (eg. sleepwalking / nightmares, etc.)
Often used in a sleep lab, in conjunction with other objective measures (eg. EEG / EOG, etc.) for accuracy
Helpful as multiple people can view / interpret the recording at once.
Can be inconclusive, and interpretation is inherently subjective.
Circadian Rhythm
Circadian rhythms are biological processes in all animals that coordinate the timing of the activity of body systems over a 24-hour period.
Ultradian Rhythm
Ultradian Rhythms are biological processes that coordinate the timing of activity of body systems over periods of less than 24 hours.
Ultradian rhythms may last from a few minutes to a few hours.
REM
Rapid Eye Movement (REM) sleep is often referred to as paradoxical sleep. It seemingly involves your brain being the most active however your body is at rest (Sleeping).
The most vivid and memorable dreams occur during REM sleep. A period of REM occurs at the end of each sleep cycle, and these periods get longer and closer together as sleep progresses.
Physiological Changes Experienced:
- Eyes make quick darting movements behind closed eyelids
- Voluntary muscles are seemingly paralyzed and twitch intermittently.
NREM 1
NREM Stage 1 is a transitional phase between wakefulness and sleep. It is considered to be light sleep.
NREM 2
NREM Stage 2 is also considered light sleep.
NREM 3
Is considered deep sleep.
Suprachiasmatic Nucleus
Also known as the SCN, the Suprachiasmatic Nucleus is a master body clock in the hypothalamus that regulates body activities to a daily schedule and wakefulness.
The SCN can be influenced by external cues as Zeitgebers, which include things such as exercise, social activity, eating patterns and temperature.
Melatonin
Melatonin is a hormone that induces drowsiness and decreases cell activity.
The SCN helps to regulate the release of melatonin, usually by the detection of either incoming light or darkness. At night when the eyes can’t detect any light, the SCN sends a message to the pineal gland in the human brain. The stimulates the release of melatonin.
Cortisol
Newborns: Sleep Patterns
Total Hours: 16 hours a day
% REM: 50%
% NREM: 50%
Other Info:
Infants: Sleep Patterns
Total Hours: 14 hours
% REM: 35%
% NREM: 65%
Other Info:
Between 3-6 months the circadian rhythm starts to influence sleep.
Children: Sleep Patterns
Total Hours: 11-12 hours
% REM: 20-25%
% NREM: 75-80%
Other Info:
Adolescents: Sleep Patterns
Total Hours: 9 hours
% REM: 20-25%
% NREM: 75-80%
Other Info: The experience a circadian rhythm shift as a result of melatonin being released later in the evening.
Adults: Sleep Patterns
Total Hours: 7-9 hours
% REM: 20%
% NREM: 80%
Other Info: 5 cycles a night lasting 90mins.
Elderly: Sleep Patterns
Total Hours: 7-9 hours
% REM: 20%
% NREM: 80%
Other Info:
The ABC’s of Partial Sleep Deprivation (Psychological Effects of Sleep Deprivation)
Affective Functioning (Emotional):
- Emotional outbursts
- More irritable
- Feeling sad of depressed
- Mood vulnerability
Behavioral Functioning (Observable Actions):
- Trouble controlling behavior
- Risk-taking behavior
- Taking longer to finish (or not finishing tasks)
Cognitive Functioning (Mental Processing):
- Memory trouble
- Decreased alertness
- Poor concentration
- Shorter attention span
- Lack of motivation
Physical Effects of Sleep Deprivation
- Hand tremors, drooping eyelids, difficulty focusing eyes, higher pain sensitivity.
- Slower heart and respiration rates, lower body temperature.
- Impaired functioning of immune system and reduced production of hormones.
- Sleep debt and Microsleeps
Sleep Deprivation vs. BAC
Delayed Sleep Phase Disorder (DSPD)
Involves a shift in the circadian rhythm so that people fall asleep/feel tired later at night, and thus wake up later in the morning.
Advanced Sleep Phase Disorder (ASPD)
Involves a shift in the circadian rhythm so that people fall asleep/feel tired earlier at night, and thus wake up earlier in the morning.
Shift work
Treatment for Circadian Phase Disorders (Bright Light Therapy)
Bright Light Therapy is used to treat people suffering from a circadian phase disorder, whereby the aim is to re-set the biological clock (SCN) and regulate a person’s sleep-wake schedule they desire of require.
Zeitgebers
Zeitgebers are environmental cues, such as light, temperature and eating patterns that can synchronize and regulate the body’s circadian rhythm, signaling to our brains to do things at a certain times.
Daylight and Blue Light
Daylight is the primary zeitgebers impacting the human circadian rhythm.
As mentioned previously, light is responsible for activating the Superchiasmatic nucleus is the brain, which influences the release of melatonin by the pineal gland.
Blue light is a range of light wavelengths that are visible to the human eye.
Temperature
- Body temp decreases in the early evening.
- Sleep onset occurs when body temperature is in its greatest decline.
- Lowest body temperature happens about 2h after sleep onset
- Core body temperature drops when skin warming occurs; blood flow increases to the skin (we also use bedding) helping to initiate sleep, but then heat is lost from the body.
Eating and Drinking Habits
The Superchiasmatic nucleus is not largely influenced by the timing of meals provided enough food is ingested.
However, the superchiasmatic nucleus is affected by long-term severe food deprivation, calorie restriction and perceived starvation..
