sleep and dreaming

• what does the S in the benefits of sleep stand for?

  safety: sleep protects from danger from predators
• what does the H stand for in the benefits for sleep?

  healthy brain - REM sleep resets the brain, memories consolidated, protects established memories, decision making, creative connections and removes toxins.
• what does the E stand for in the benefits of sleep?

  emotional stability - reduces cortisol levels, a hormone related to stress
• what does the P stand for in the benefits of sleep?

  physical repair - slow wave sleep helps heal calls especially those in the cardiovascular system and helps maintain hormone balance as well as increasing immune activity.
• what are the 5 stages of sleep?

  stage 1, stage 2, stage 3, stage 4, REM
• brain activity in stage 1 of sleep: slowing and synchronized. alpha waves becoming theta waves.
• brain activity in stage 2 of sleep: theta waves dominate but are interrupted by brief bursts of activity known as sleep spindles.
• sleep spindles - brief bursts of activity whilst asleep
• brain activity in stage 3 of sleep: delta waves as its in slow wave sleep.
• brain activity in stage 4 of sleep: deepest level of sleep. consists of low frequency, high amplitude fluctuations. brain cements information into memory
• brain activity in stage 5 (REM) : thalamus is active, sending cortex images, sounds and other sensations filling dreams. dynamic brain. theta waves.
• physical features of stage 1 - drowsy, easy to wake, people may not realise that they were asleep. muscle spasms followed by sensation of falling
• physical features of stage 2 - body goes into a deep state of relaxation, drop of body temp, slow breathing and heart rate
• physical features of stage 3 sleep - muscle tone, pulse and breathing rate decrease, may have some body movements but hard to wake up
• physical features of stage 4 - voluntary muscles become immobilised, slow wave sleep.
• physical features of stage 5 (REM) sleep - dreams occur as eyes move behind the eyelids, desynchronized brain activity.
• percentage of time spent in stage 1 = 10%
• percentage of time spent in stage 2 = 50%
• percentage of time in stage 3 = 10%
• percentage of time in stage 4 = 10%
• percentage of time in stage REM - 20%
• sleep disorders - behaviour which affects normal sleep patterns
• sleep onset insomnia - problems falling asleep
• sleep maintenance insomnia - problems staying asleep
• what causes sleep onset insomnia?

  anxiety / stress, nicotine or caffeine before bed, heavy meals before bed, blue light, physical pain.
• a complete sleep cycle takes around 90 minutes
• what causes sleep maintenance insomnia?

  depression, alcohol, restless leg syndrome, sharing a room with someone who snores, menopause
• endogenous pacemakers - internal biological clocks that manage bodily rhythms
• exogenous zeitgebers - features of the environment (either physical or social) that may help manage bodily rhythms
• the suprachiasmatic nucleus is found in the ...

  hypothalamus
• the suprachiasmatic nucleus is responsible for passing information to the pineal gland in order to trigger melatonin production
• melatonin - the hormone that makes one sleepy / tired
• 1. if there is light, it travels through the optic nerve
  2. signal passes to the suprachiasmatic nuclei (SCN) in the hypothalamus
  3. the hypothalamus tells the pineal gland to start stop producing melatonin
  4. you start to feel awake / alert.
• 1. when it gets dark, the hypothalamus tells the pineal gland to start producing melatonin
  2. as a result you get sleepy
• Freudian slip - unintentional speech that reveals unconscious thoughts or feelings
• the unconscious mind - the part of the mind that people are not aware of but holds involuntary thoughts / memories
• how do you study the unconscious mind?

  through analysing dreams
• part of the unconscious mind is the ID (instincts). this represents our urges and instincts especially those surrounding sex and aggression.
• repression is a defence mechanism that works by pushing back unwanted desires into the unconscious mind.
• Freud suggested that the ID challenges the ego which helps us keep in touch with reality whilst awake as its defences are weakened.