human consciousness and sleep Flashcards
chapters 9-13
what is consciousness?
the awareness of our own thoughts, feelings and perceptions and our surroundings at any given moment. it is considered a psychological construct because it is believed to exist, but we cannot see, touch or measure it.
what are the levels of the consciousness continuum?
hyperarousal
focused selective attention
divided attention
daydreaming
sleep
anaesthetised
coma
what is normal waking consciousness?
the states we experience when we are awake and aware of our thoughts, feelings and perceptions from internal events and the surrounding environment; we experience a real sense of time and place and create our reality and a baseline to judge all other states of consciousness
what are altered states of consciousness?
any state of consciousness that deviates from normal waking consciousness, in terms of awareness, perceptions, memories, thinking, emotions, behaviours and one’s sense of time, place and self-control; it can be deliberately induced or occur naturally
what is the stream of consciousness and its qualities?
an analogy that explains the consciousness as an ever-changing stream of thoughts that can shift smoothly from one moment to the next, like water flowing in a stream
- continuous
- ever changing
- highly personal
- selective
- active
what is attention?
refers to the information you are actively processing, either consciously or outside your conscious awareness
what is selective attention?
the ability to focus on only select stimuli or objects in the environment and to filter out other distractions
what is selective inattention?
the way we attend to (or do not attend to) information that may be relevant but emotionally upsetting
what is divided attention?
the ability to attend to and perform multiple activities at the same time
what are automatic processes?
require very little effort or mental effort to be performed well and generally don’t interfere with other processes, enables us to have divided attention
what are controlled processes?
require mental effort to focus attention on the required task, requires selective attention
what does an EEG do?
detects, amplifies and records electrical activity in the brain in the form of brainwaves. measures changes in consciousness from changes in brainwave activity.
what does an EOG do?
detects, amplifies and records electrical activity in the muscles that allow the eye to move. particularly useful in determining whether a person is in REM or nREM sleep
what does an EMG do?
detects, amplifies and records the electrical activity of heart muscles. when someone is awake, activity on EMG recordings is high, during sleep the activity is moderate to low and during REM it is virtually non-existent
what is the circadian rhythm?
- the sleep-wake cycle of humans
- a biological rhythm that occurs approximately once every 24 hours
- determined by an internal body clock (the suprachiasmatic nucleus) located in the hypothalamus
what hormones are involved in the sleep cycle?
released by the superchiasmatic nucleus
- melatonin: drowsiness, is released at night and stops releasing when we see light in the morning
- cortisol: alertness, is released when we see light in the morning
explain stage 1 nREM
- the transition from being awake to being asleep
- relaxed state known as a hypnogogic state
- may experience hallucinatory images, involuntary muscle twitches and the “falling” feeling
- very brief and can be easily awoken
- sometimes called the pre sleep stage
explain stage 2 nREM
- true sleep begins
- still fairly easy to be awoken, despite being in a deeper stage of sleep
- eyes stop rolling, muscles become further relaxed and
- breathing and heart rate continue to decrease
- accounts for around 50% of our total sleep
explain stage 3 nREM
- brief transitional stage that marks the beginning of deep sleep
- become less responsive to external stimuli and more difficult to awaken
- if awoken, we are groggy and disoriented
- eyes do not move, muscles are relaxed, heart rate and breathing continue to become slower and more regular
explain stage 4 nREM
- the deepest stage, extremely difficult to wake up
- consciousness level is very low
explain the REM stage
- eyes move rapidly for short bursts of time
- lighter than stages 3 and 4, easier to wake up from
- if woken during REM sleep, likely to report we were dreaming
- heart rate, blood pressure and breathing increase and fluctuate
- no muscle tension, muscles are completely paralysed in order to prevent sleepwalking
- lighter sleepers and more anxious people are more likely to dream
how does sleep change as we age?
- total time spent sleeping decreases
- older people struggle to reach stage 3 and 4 of nREM
how does sleep change in adolescence?
- teenagers experience delayed sleep-wake phase disorder: a circadian phase disorder that delays sleep patterns
- in teenagers, the release of sleep-wake hormones is delayed by up to 2 hours, and as a result they tend to want to go to sleep later and wake up later
- teenagers need 9-10 hours of sleep per night
explain the evolutionary theory of sleep
- sleep serves as a means to increase an animal’s chance of - survival in its environment
sleep patterns have adapted to periods of light and darkness, to meet the demands of the environment, and depending on whether the animal is a predator or prey - animals with vision suited to day time sleep at night and carry out their risky tasks such as hunting, during safer daylight hours
