Sleep and Dreaming Flashcards
Consciousness
Awareness of objects and events in the external world and of our sensations, mental experience and existence at any given moment.
Normal Waking Consciousness
Awareness of internal states and external surroundings when we are awake and unaffected by sleep, drugs, or other states.
Altered State of Consciousness
Anything that is not normal waking consciousness.
Sleep
A reversible behavioural state of perceptual disengagement from and unresponsiveness to the environment.
Suprachiasmatic Nucleus
Found within the hypothalamus.
Responsible for controlling circadian rhythms. They are sleep wake cycles that occur every 24 hrs.
Detects the amount of light being sent to the brain for processing and influences the amount of melatonin being released into bloodstream.
Main role is to regulate the onset (beginning) of sleep.
Melatonin
Hormone that is produced and secreted in the pineal gland.
Gradually builds up during the day. High levels of melatonin cause sleepiness. Once levels reach a critical level, a person falls asleep. The more light, the less melatonin.
Reticular Activating System
Found in Thalamus.
Regulates cortical arousal. i.e. alertness.
When sleeping, there is a state of low cortical arousal sp the role of the RAS in sleep is to maintain the sleep state.
Influences when we are asleep or awake by restricting the amount of simulation cerebral cortex receives, allows us to stay asleep.
Major parts of RAS = reticular formation and thalamus.
Reticular Formation
Through the brain stem and up into mid brain.
Reducing the stimuli that is sent to cerebral cortex.
Thalamus
Transfer station for information from senses.
Transfers neural information form the reticular formation to cerebral cortex.
Filters sensory information and closes sensory pathways during sleep.
Sleep Research
Takes place in sleep laboratories.
Many devices are used to monitor and record physiological responses of patients studied there.
Electroencephalograph (EEG)
Detects, amplifies and records electrical activity generated by the brain (D.A.R.E). Distinguishable patterns of electrical activity (called brain waves).
Amplitude
Measured in the wave height
Frequency
How close waves are to one another
Electromyograph (EMG)
Detect, amplify and records the electrical activity of muscles.
Shows strength of electrical activity occuring in the muscles, changes in muscle activity and muscle tone.
Information obtained by attaching electrodes to particular muscles and recorded as line graphs.
Most aware to Least Aware waves
Batman Ate The Donut (most to least)
Beta waves
Alpha waves
Theta waves
Delta waves
Beta waves = most aware (e.g. Stage 1 or REM sleep) to Delta waves being heavy sleep (stage 4).
Electro-oculogram (EOG)
Device for measuring eye movements or eye positions by detecting, amplifying and recording electrical activity in eye muscles.
Done through electrodes attached to area of the face surrounding the eyes. Recordings are displayed as line graphs.
Hypnogram
Graph that shows sleep cycles across one night sleep.
x - axis = time/duration of sleep
y - axis = stages of sleep NREM 1-4 + REM
Two types of sleep
- Non Rapid Eye Movement Sleep (Non - REM)
- Rapid Eye Movement Sleep (REM)
How much sleep is required for different ages
Infant = ~13.5hrs of sleep, majority = non-REM
Childhood = ~11 hrs of sleep, 80/20 non-REM/REM sleep
Adolescent = ~8.5 hrs of sleep, 80/20 non-REM/REM sleep
Adult = ~6 - 8 hrs of sleep, 80/20 non-REM/REM sleep
Elderly = continually decrease to ~5-6 hrs, 80/20 non-REM/REM sleep, frequently wake up in the night.
NREM Sleep
‘Non - Rapid Eye Movement’
80% of our sleep time
4 different stages in which our sleep progresses from a stage of light sleep to the stage of deepest sleep and back again.
Every stage of sleep is dominated by a particular identifiable brain wave pattern recorded by an EEG.
NREM Stage 1
5- 10 min.
- gradually lose awareness
- occurs when we drift into and out of a true sleep state
- lower lvl of bodily arousal - such as decreased heart rate, body temp. + muscle tension.
- theta waves replace alpha waves –> relaxed wakefulness
- sometimes experience hypnic jerk
NREM Stage 2
20 min.
- light sleep.
- sleep spindles + K complexes (EEG) –> Specifically at stage 2. Considered hallmark of being truly asleep.
- body movements lessen
- breathing becomes more regular
- blood pressure and temperature continue to fall and heart rate is slower
NREM Stage 3
10 min.
- extremely relaxed
- less responsive to the outside world
- difficult to wake.
- 20-50% delta waves
- heart rate, blood pressure and body temp. = continue to drop and breathing rate continues to be slow and steady
NREM Stage 4
20 min.
- deepest stage
- completely relaxed and difficult to wake.
- as night progresses, less and less time is spent in stages 3 and 4
- 50+% delta waves
- sleepwalking, sleep talking, night terrors and bed wetting occur in stages 3 and 4
REM Sleep
High level of brain activity but semi paralysis.
- Bursts of rapid eye movements
- Beta-like waves
- Thought to be associated w mental recuperation
- Associated w dreaming. Most dreaming occurs in REM sleep. Less dreams and are more vivid and easy to remember and have a narrative.
- Increases as night progresses.
- More difficult to wake.
- Semi paralysis = internal functioning more active then during NREM. However, the sleeper is totally relaxed and paralysed.
Purpose: consolidating or embedding new memories by strengthening new formed neural connection; important biological need.
What is dreaming?
Physiologically and psychologically conscious state. Rich array of sensory, motor, emotional and experiences.
What are the two dream theories?
Psycho-Dynamic Theory
Activation-Synthesis Hypothesis
Sleep hygiene
Habits that people have that help them have a good night’s sleep.
Sleep Phenomena
Observable experiences that occur during sleep. More common in childhood and early adolescence.
Nightmares
Bad, frightening dreams.
Occur during REM sleep.
Have a good recall of the experience.
Able to calm down and return to sleep.
Night Terrors
Sudden awakening from sleep in extremely distressed state.
May wake screaming, walk in a state of panic, terrified expression, dilated pupils, little or no recollection after the event.
Increased heartrate, irregular breathing.
Occurs in stages 3 and 4 NREM sleep only.
Speak incoherently, difficult to console.
Sleep disorders
Problem that disrupts the normal NREM - REM sleep cycle.
Parasomnias
Type of sleep disorder which involves engaging in abnormal activities or tasks while sleeping.
e.g. Sleep - walking
Dyssomnia
Consistent problems with falling asleep, staying asleep or timing sleep.
e.g. sleep - onset insomnia
Causes and treatments for Dyssomnia
Causes:
- Psychological: stress, fear or anxiety.
- Physiological: pain, alcohol and drug use.
Treatment:
- Medication (short term)
- Dealing with underlying cause
- Exercise and developing behavioural routines.
Hypersomnia
Excessive sleepiness or sleep of excess duration.
12 hours or more sleep per day.
Cause: Insomnia, depression, substance abuse, sleep apnea
Sleep Apneoa
Temporary suspension in breathing. Ends in a loud snore, body jerk or arm flinging.
Sleep Theories
Restorative Theory of Sleep
Survival Theory of Sleep
Restorative theory of sleep
Allows for body to recover and replenish energy used throughout the day.
NREM = restoring body
REM = restoring mind
Sleep = improves immunity to disease, increase alertness and consolidates memories.
Survival Theory
Enhance the survival of an organism by making it inactive during the most vulnerable time of the day.
Less likely to attract predators
Depends on an animal’s vulnerability to predators
Conserves energy
Partial Sleep Deprivation
Some time but not sufficient sleep.
Selective sleep deprivation
enough of a particular type
Chronic sleep deprivation
Loss of sleep over a prolonged period of time.
Acute sleep deprevation
No sleep for short term period.
Ethical concerns of sleep deprivation experiments.
Participants could be harmed and participants are not allowed to be harmed in any way during an experiment.
Participants may not agree and they must be aware of potential risks of experiment (Informed Consent).
