chapter 7 Flashcards
consciousness
the awareness of your own internal mental processes, including your thoughts, feelings, sensations and perceptions, and your awareness of the external world around you.
what is consciousness?
- Consciousness is unique, subjective and constantly changing, and can be thought of as what information takes possession of your mind.
e.g. one moment you may be aware of the words that you are reading on this page, then you realise you have been daydreaming about having your favourite dinner tonight, then the contents of your consciousness may shift to your friend who is sitting next to you and asking you a question
psychological construct
-a concept that cannot be objectively observed or measured directly through the collection of data, but is widely understood to exist.
-Consciousness is considered a psychological construct because it cannot be objectively observed or measured through the collection of data, but it is widely understood to exist.
-it is impossible to precisely know someone else’s conscious experience
-There is no one particular brain structure in which our consciousness resides
-we can only indirectly measure it through qualities that are more easily assessed, such as physiological changes or observable behaviours, or through self-report methods.
normal waking consciousness and altered states of consciousness
-our consciousness is continuously shifting through different levels of awareness. (it doesn’t turn off or on)
-e.g. you may be in a state of focused attention during a maths test, a state of lethargy at the end of the school day, a daydreaming state on the bus ride home, and then finally a state of sleep with periods of dreaming
-The various states of consciousness that we experience are broadly categorised into normal waking consciousness and altered state of consciousness.
normal waking consciousness
-a state associated with being aware of our internal and external environments
-We experience normal waking consciousness in everyday activities when we are awake and have a regular level of awareness.
-we can manage out thoughts and behaviour
-our thoughts and perceptions are organised and clear
SUCH AS: such as when reading a book, chatting with a friend or having dinner with our family.
altered state of consciousness
-any state that differs in awareness when compared to normal waking consciousness
-In altered states of consciousness, our levels of awareness are lower or higher
than in normal waking consciousness.
-e.g. A child daydreaming on a long car ride or an elite tennis player serving a winning point are both in an altered state of consciousness
-There is also a change in mental processing where perceptions or thinking may be altered
naturally occurring altered state of consciousness
induced altered state of consciousness
N.O.A.S.O.C:
-an altered state of consciousness that occurs without any external Influence
I.A.S.O.C:
-an altered state of consciousness that has been brought about on purpose.
sleep
-a naturally occurring and reversible altered state of consciousness, characterised by a reduction in awareness and responsiveness to external surroundings
-During sleep, there is unique brain wave activity and other distinguishable physiological changes.
-These changes help to differentiate sleep from other altered states of consciousness that might result from brain injury or taking substances.
-sleep may also be considered a psychological construct
over the course of the night you will experience two different types of sleep:
- rapid eye movement (REM) sleep
- non-rapid eye movement (NREM) sleep
During an eight-hour sleep episode, the average person will experience about five sleep cycles, each lasting approximately 90 minutes and featuring distinguishable repetitive patterns of REM and NREM sleep
NON-RAPID EYE MOVEMENT (NREM) SLEEP
-a type of sleep characterised by a progressive decline in physiological activity
-NREM sleep consists of three distinct stages and takes up around 80% of a sleep episode in people of school age and older.
- It is thought that our body is repairing itself during NREM sleep.
-NREM Stage 1 (N1)
-NREM Stage 2 (N2)
-NREM stage 3 (N3)
NREM Stage 1 (N1)
- a transitional phase between wakefulness and sleep.
-It is considered to be light sleep; physiological responses begin to slow down, including brain activity, heart rate and body temperature.
-the period when a person ‘dozes off’ to sleep and when they may most easily be woken up.
-As a sleep episode progresses, a person may not experience much more time
in N1.
-If they are not disturbed for a couple of minutes in N1, a person quickly moves into NREM Stage 2 (N2).
NREM Stage 2 (N2)
- is also considered light sleep, during which physiological responses continue to slow down.
-A person still wakes relatively easily during N2; however, bursts of brain activity help resist being woken by environmental stimuli such as noises.
-N2 is the stage of sleep that is experienced the most throughout a sleep episode.
NREM Stage 3 (N3)
- is considered to be deep sleep, during which physiological responses are at their slowest and a person is most difficult to wake up
-N3 is known as ‘slow-wave sleep’ due to brain activity being at its slowest.
-During a sleep episode, N3 is experienced more in the first half of the night than in the second half of the night.
-. As a sleep episode progresses, a person
experiences less N3 sleep, and may not experience it at all in the last one or two sleep cycles of a typical night.
-People of different ages spend different
amounts of time in N3
RAPID EYE MOVEMENT (REM) SLEEP
-a type of sleep characterised by quick darting of the eyes behind closed eyelids and an increase in physiological activity.
-A period of REM occurs at the end of each sleep cycle, and these periods get longer and closer together as the sleep episode progresses, which means you have
more REM in the second half of sleep than in the first half.
-REM sleep also differs markedly across different ages, but typically takes up 20% of a sleep episode in people aged around 5 years and older.
-If you have less sleep than normal, you may experience more REM sleep when you next sleep.
-It is thought that our mind is repairing itself during REM sleep.
during REM sleep:
-During REM sleep, brain activity resembles wakefulness, and heart rate and breathing rate increase.
-Voluntary muscles are seemingly paralysed and twitch only intermittently.
-The most vivid and memorable dreams occur during REM sleep.
hypnogram
-a line graph that represents the stages of sleep plotted against time
- displays the sleep architecture or patterns of a sleep episode, with a typical night’s sleep for an adult consisting of five sleep cycles featuring REM and NREM sleep.
-time on x-axis (hours of sleep), types of sleep y-axis (wakefulness at the top -REM- and deepest sleep at the bottom-N3)
-shows how a person’s sleep progresses through several sleep cycles consisting of REM sleep and the three stages of NREM sleep, over the course of a night.
measuring sleep
These techniques can allow a person to detect and record features such as:
-the onset of sleep
-sleep duration
-sleep quality
-awakenings during sleep
-any body movements
-wake-up time.
This data is useful for diagnosing sleep disorders, tracking how a person’s sleep is affected by various factors such as new medication, or even improving the performance of athletes
the different techniques for measuring sleep
-electroencephalography
-electromyography
-electro-oculography
-sleep diaries
-video monitoring.
-These techniques are often combined in a kind of sleep study called polysomnography. (a multi-parameter
sleep study used as a diagnostic tool in sleep medicine)
- Electroencephalography (EEG)
-a technique that detects, amplifies and records the electrical activity of the brain
- Electroencephalography (EEG)
-when undertaking an electroencephalogram:
-electrodes are attached to a person’s scalp or through a cap or headset
-The electrodes detect the synchronised electrical impulses of many neurons communicating together just beneath the scalp at the surface of the cortex.
-Wires connected to the electrodes transmit this data to an instrument (electroencephalograph) that amplifies the signals to a readable level and then sends them to a computer, where they are recorded as brain wave patterns and
interpreted by a specialist
EEG CONTINUED
-the brain wave recordings produced by an EEG are summaries of the activity of thousands of neurons in the area (the electrical impulse of one neuron is not strong enough to be detected by an EEG)
-Different types and stages of sleep produce different brain waves, and EEGs may be used to identify a particular stage or abnormal brain activity that differs from what would usually be expected.
-e.g. abnormal brain activity can indicate a sleep disorder.
- Electroencephalography (EEG)
brain waves:
-There are several main types of brain waves: beta, alpha, theta and delta, which are characterised by specific patterns of activity and occur at different times during wake and sleep.
-The brain wave patterns differ in terms of their frequency and amplitude.
- Electroencephalography (EEG)
Brain waves: frequency
-The frequency of a brain wave indicates the speed of the brain waves or how much activity is occurring every second.
- Frequency can be visually identified in a brain wave recording according to how close together the waves are and the number of times the wave repeats in a 1-second interval.
-Slower-frequency brain waves are prevalent when we are tired, relaxed or asleep.
-Faster-frequency brain waves are prevalent when we are awake and alert
- Electroencephalography (EEG)
Brain waves: amplitude
-The amplitude of a brain wave indicates the intensity or strength of the brain wave, or how many neurons are firing at the same time together.
- can be visually identified in a brain wave recording as the height of the brain waves or the distance between the peaks and troughs
-Higher peaks and lower troughs indicate more synchronised brain activity from multiple neurons working on a similar task .e.g. sleep
-lower peaks and troughs indicate groups of neurons are working on different tasks .e.g. driving a car.
brain waves link to sleep (NREM & REM)
-The brain wave types relate to the person’s level of awareness or state of consciousness, and a general pattern across the four brain wave types shows that as the frequency of a brain wave decreases, the amplitude increases.
- As a person drifts into the deeper sleep stages of a sleep cycle, their brain wave activity decreases, as indicated by progression through the four brain wave types.
The increase in brain activity during REM sleep is indicated by faster brain wave patterns
