sleep Flashcards
define sleep
a regular and naturally occurring altered state of consciousness that involves a loss of awareness and
disengagement with internal and external stimuli
- follows an internally regulated cycle of about 24 hours
biological rhythyms
cyclic changes in bodily functions or activities that repeat themselves through time in the same order
define circadian rhythms
a circadian rhythm is a biological rhythm that involves changes in bodily functions or activities that occurs as a part of a cycle with a duration of about 24 hours.
- human sleep wake cycle
what is the “master” controlling thus sleep wake cycle
an area of the brains hypothalamus called the suprachiasmatic nucleus (SCN) which biological clock that regulates the timing and activity of sleep wake cycle (through the light as that is an environmental cue affecting the cycle)
SCN
-receives information about the amount of light from the eyes and adjust our sleep wake cycle accordingly
- It signals the nearby pineal gland to produce and secrete more or less melatonin in relation to light intensity
- located above the hippocampus, close near to optical nerve (as it detects light from external environmnent)
how does melatonin relate to sleep
- associated with alertness
- high melatonin level is associated with great drowsiness and vice versa
- the amount that is secreted varies with the amount of light that is detected
ultradian rhythms
is a biological rhythm that involves changes in bodily functions or activities that occurs as part of a cycle shorter than 24 hours
- e.g. heart beat, respiration, hunger, secretiom of hormones and human sleep (occurs every 90 minutes)
what is rem
rapid eye movement
what is nrem
non rapid eye movement
- includes stages 1,2,3,4
- approximately 75-80% of total sleep is spent with nrem
- reduction in physiological activity
- as stages progresses, it indicates a deeper sleep, brain waves get slower and bigger, breathing and heart rate slows down and blood pressure drops
sleep cycle consists of what
- consist of both NREM and a period REM sleep
- each cycle is usually repeated 5-6 times each night, depending on the duration of the sleep
sleep onset
sleep latency
hypnagogic state
techniques to measure sleep
- measurement of physioogical responses (EEG, EMG & EOG)
- sleep diaries (self reports)
- video monitoring
measurement of physiological response associated with sleep
- EEG (electroencephalography), it detects, amplifies and records the electrical activity of the brain - placed on the brain
- EOG ( electrooculography), it detects, amplifies and records the electrical activity of the muscles around the eyes!!!!!!! - placed around the eyes
- EMG (electromyography), detects, amplifies and records the electrical activity of muscle movements and tension - placed near muscles on the face/body
EEG and brainwaves
- it DARES activity of the brain
- displayed in brain waves
- BATD (beta, alpha, theta and delta)
pros and cons of EEG
pros:
- useful in providing general infromation about brain wave activity in real time without being invasive
- assist with diagnosis of medical conditions(brain damaged and neurological disorders)
cons:
- poorly measures neural activity that occurs below the outer layer of the brain
- does not provide detailed information about which particular structures of the brain are activated and what their specific functions might be
- just provides a summary of all the activity of neurons firing within different areas of the brain
beta
- high frequency
- low amplitude
- irregular
- associated with normal waking consciousness when alert
alpha
- high frequency (slower than beta)
- low amplitude (slightly larger than beta)
- like a teeth of a comb
- relax, calm, internally focused, wakeful with eyes closed
theta
- medium frequency (slower than beta and alpha)
- mixture of high and low amplitude waves
- associated with drowsiness, falling asleep, creative activities, deep meditative state
delta
- lowest frequency
- highest amplitude
- associated with deepest stage of sleep, periods of REM and unconsciousness
limitations of sleep diaries (self reporting)
- measurement based on personal judgement (subjective), which can be difficult to communicated and compare to others
- accurately describing our dreams or what we are thinking and feeling can be difficult.
- integrity of participants, sharing personal thoughts can be challenging
- This is unlikely if they were in an altered state of consciousness, such as sleep. Dreams are usually quickly forgotten, if remembered at all.
- particpants may unintentially leave out key information’
- can the researcher interpret the descriptions accurately and reliably
video monitoring
- insight on how we behave in different stes of consciousness
- can observe participants when they are awake
limitations of video monitoring
- does not provide insight on what is going inside the body or what the participants are experiencing
- relies on the researcher to interpret the behaviour
- subjective and open to bias
SCN detetcst
- decreases alertness when it is dark (cortisol is decreased)
- increases alertness (increases temp body, stimulates cortisol
melatonin
- no addictive properties
