Unit 3: Sleep and Dreaming Flashcards
What is Normal waking consciousness?
our awareness of internal states and external surroundings when we are awake and unaffected by sleep, drugs or other states
unconscious vs conscious
conscious= deliberately or knowingly doing something
unconscious= automatically doing something, without having to think abt it e.g breathing
Characteristics of consciousness
-conscious experience is associated with the activity of the neurons in the brain.
-described as: personal/individual, selective (choose what you think abt), continuous, changing
States of consciousness
total awareness (of internal and external stuff) -> focused, selective attention, controlled processes= NWC -> Daydreaming=NWC -> Meditative state=ASC -> Hypnotised= ASC -> asleep=ASC -> anaesthetised (drug induces, same level as alcohol)=ASC -> unconscious (coma)=ASC-> Complete lack of awareness=death
Characteristics of NWC
-attention
-controlled vs automatic processes
-content limitation
Characteristic of NWC
-attention
- involves focusing on specific stimuli and ignoring other stimuli
-can be focused internally or externally
-can be focused/ selective attention or divided
selective/ focused attention
-choosing to (either intentionally or through circumstance) attend to certain stimuli while overlooking other stimuli
Factors that influence what we focus on
-if stimuli is important to us= more likely to direct our attention to it
-changes in stimulation e.g teacher goes quite/ shouts= draws attention
-novel stimuli= if its unique/new/ haven’t experienced it before more likely to draw our attention
Divided attention
-the ability to distribute one’s attention and undertake more than one activity (has to be simple) at same time e.g singing while cleaning
Characteristic of NWC
-Controlled processes
-when info processing requires conscious, alert awareness and mental effort
-focused on achieving a particular goal
-associated with a difficult or unfamiliar task
-linked to selective attention
-involves serial processing= doing one thing than another e.g driving
Characteristic of NWC
-Automatic processes
-when info processing involves little conscious awareness and mental effort
-easy or familiar tasks
-involves parallel processing=doing two things at once
-linked to divided attention
e.g speaking and walking
Characteristic of NWC
-Content Limitation
-content refers to the type of info held in consciousness
ROLLOC= thoughts are more, Restricted, Organised, Limited, Logical, Ordered and Controlled compared to ASC
Other Characteristic of NWC
-clear perception
-ability to process internal and external info
-memory ( ability to store and retrieve info)
-time orientation (ability to focus on past, present and future)
-emotional awareness (normal range of emotions and awareness of feelings
The lower the level of processing?
the lower the level of consciousness
Where is the Superchiasmatic nucleus located?
-is a tiny region of the brain in the hypothalamus
-it is situated directly above the optic chiasm
function of SCN?
-it is responsible for controlling the circadian rhythms= sleep wake cycles that occur approx.. every 24 hrs.
-it’s main role is for regulating the onset of sleep
How does the SCN control the circadian rhythms?
-detects the amount of light being sent to the brain for processing and send this info to the pineal glad to influence the amount of melatonin being released into the bloodstream
Role of melatonin?
-it gradually builds up during the day
-high levels of melatonin lead to sleepiness which creates sleep pressure w/a lower levels, increase awareness
-once levels of melatonin reach a critical level a person will fall asleep
-levels of melatonin is influenced by SCN
-the more light= less melatonin
What is the reticular activating system? (RAS)
it is a network of neurons that extends out from the reticular formation (RF) to different parts of the brain and spinal cord
function of RAS
-to regulate cortical arousal, alertness to increase or decrease sleep
-when we’re sleep, we’re in a state of low cortical arousal, so the role of RAS in sleep is to maintain the sleep state by restricting the amount of stimulation the cerebral cortex receives, limits sensory input during sleep to enable perceptual disengagement from environment
-main parts are the reticular formation and thalamus
Function of Hypothalamus in sleep?
contains SCN which controls the onset of sleep.
Function of Hippocampus in sleep?
a memory region active during dreaming
Function of Amygdala during sleep?
an emotion center active during dreaming
Function of Thalamus during sleep?
in the RAS, filter, prevents sensory signal from reaching cortex by closing sensory pathways during sleep, maintains sleep
Function of Reticular formation?
in the RAS, regulates the transition between sleep and wakefulness, when RF is stimulated= alertness, when RF is damaged=coma
Function of Pons during sleep?
helps initiate REM sleep
What is the reticular formation?
structure running through the brain stem and up into the mid brain
Damage to Thalamus results in?
-can cause loss of any sense, except smell
-lead to cerebral cortex not receiving sensory info
-attention difficulties= what to ignore and what to attend to
-lower arousal from lethargy (fatigue, tiredness) to coma
What is amplitude?
-size of wave, relates to the intensity of the wave and is measured in wave height
-high electrical activity= smaller waves and lower amplitude
-low electrical activity= larger waves and increased amplitude
What is frequency?
-speed of wave, relates to how many waves occur over time and is measured by how close the waves are to one another
-high electrical activity= increased frequency (fast) and waves are closer together
-low electrical activity= low frequency (slow) and waves are further apart
Types of Brainwaves
-Batman Ate The Donut
-Beta, Alpha, Theta, Delta
-Beta waves with most aware and highest electrical activity to Delta with heavy sleep and least electrical activity
Beta waves
-high frequency, low amplitude, and are irregular
-associated with NWC when alert, attentive to external stimuli and intensive mental activity
Alpha waves
-high frequency but slower than beta, and low amplitude but slightly larger than beta
-relaxed, calm, internally focused, wakeful state with eyes closed
EEG, EMG and EOG
EEG= talk abt brain waves w/a EMG and EOG= just electrical activity
Theta waves
-medium frequency but slower than alpha and beta, and a mixture of high and low amplitude waves
-drowsiness falling asleep, awakening from sleep, creative activities, excitement, deep meditative state in which there is no awareness of external stimuli
-when falling asleep, you go from alpha to theta
Delta waves
-have the lowest frequency and the highest amplitude
-deepest stage of sleep which precedes periods of REM sleep and unconsciousness
EMG (electromyograph)
-generally show the strength of electrical activity in the muscles (not brain waves), which indicates changes in muscle activity (movement) and muscle tone (tension)
-this info is obtained by attaching electrodes to particular muscles, and are recorded as line graphs
- increase in movement and muscle tone= increase in electrical activity
EOG (electrooculogram)
-the EOG is a device for measuring eye movements or eye positions by detecting, amplifying and recording electrical activity in eye muscles (what generates electrical activity) that control eye movements
-this is done through electrodes attached to areas of the face surrounding the eyes
-displayed as line graphs
What is a Hypnogram?
-is a graph demonstrating an individual’s sleep cycles across one night of sleep.
What is a sleep episode?
one full night of sleep
What is a sleep cycle?
around 90 to 120 mins of a sleep episode
What are the characteristics of a hypnogram of a healthy adult?
-5 sleep cycles
-increasing time of REM as night goes on
-amount of time in stage 4 decreases overtime
-end of sleep time is lighter, you’re in a lighter stage e.g stage 2 or 1
-sleep for 6-8 hours and have 90 minute sleep cycles
-don’t return to stage 1 until the end of the sleep, thus it will be difficult to wake them up during the night
sleep of an infant / neonatal (3-24 months)
13.5 hours to 16 hrs
-50% REM (learning new things) and 50% NREM (period of rapid growth and development)
sleep during childhood (2-14 years) ?
11 hours, 80% in NREM, 20% in REM
sleep during adolescent (14-18years) ?
8.5 to 10hours, 80% in NREM, 20% in REM
sleep during adulthood (18-75 years) ?
6 to 8 hrs, 80% in NREM and 20% in REM (REM decreases as you get older)
sleep during elderly (75+ years) ?
-sleep duration continually decreases to 5 to 6 hours, 80% in NREM and 20% in REM
-may frequently wake up during the night for a short period of time before returning to sleep
-need less sleep b/c tend to not engage in much activity, and not much growth, according to restorative theory of sleep less NREM 3/4 (deep sleep) as you get older t/f less secretion of growth hormone
NREM sleep
-during NREM the brain is active (alpha, theta, and delta), yet not as active as during REM sleep or NWC
-consists of 4 distinct stages, in which the sleeper progresses from light to deep sleep then back again
-characterised by progressive decrease in physiological arousal, muscle tone, brain activity and decreased levels of awareness
NREM stage 1 characteristics
-occurs as we drift into and out of a true sleep state
- gradually lose awareness, still aware of faint sound
-theta waves replace alpha
-hypnic jerk b/c of muscles relaxing
-last for abt 5-10mins
NREM stage 1 physiological changes
-lower level of bodily arousal e.g decreased heart rate, respiration, body temp and muscle tension
NREM stage 2 characteristics
-light sleep
-sleep spindles (burst of high frequency) and K-complexes ( burst of high amplitude)
-less easily disturbed than stage 1, yet we can still be easily awaken
-abt 20 mins
-theta waves
NREM stage 2 physiological changes
-body movements lessen, breathing becomes more regular, blood pressure and temp continue to drop, heart rate is slower
NREM stage 3 characteristics
-10 mins
-20-50% delta waves
-extremely relaxed, less and less responsive to outside world
-difficult to wake, if woken they are usually groggy and disorientated
-sleepwalking, talking and night terror and bed wetting occur
NREM stage 3 physiological changes
heart rate, blood pressure and body temp continue to drop, breathing rate continues to be slow and steady
NREM stage 4 characteristics
-deepest stage of sleep
-50+% delta waves
-20 mins but time spent in this stage decreased through the night
-sleepwalking, talking and night terror and bed wetting occur
-difficult to wake,
muscles are completely relaxed and we barely move
-poor memory of sleep events