5.1—biological rhythms of consciousness: wakefulness and sleep

Question 1

Consciousness

Answer 1

a person’s subjective awareness, including thoughts, perceptions experiences of the world, and self-awareness.

Question 2

Biological Rhythms

Answer 2

• Different types of Biological Rhythms:
• circannual rhythm: a cycle that happens yearly (e.g. hibernation)
• infradian rhythm: rhythm that occurs longer than a day (e.g. menstrual cycle)
• ultradian rhythms: extremely frequent cycles (e.g. urination, hearth rate, breathing)
• circadian rhythms: (are the most important) internally driven daily cycles of approximately 24 hours affecting physiological and behavioural processes (e.g. hunger and sleep)

Question 3

Suprachiasmatic Nucleus (SCN)

Answer 3

• a key brain structure of the hypothalamus.
• relays light levels in the environment to the pineal gland which in turn, releases melatonin.
• explains why we are more awake during the daytime and sleepy during nighttime.

Question 4

Stages of Sleep

Answer 4

• awake
• stages 1-4
• REM sleep

Question 5

Polysomnography and Electronecephalogram (EEG)

Answer 5

• polysomnography: a set of objective measurements used to examine physiological variables.
• electronecephalogram: a device that measures brain waves.

Question 6

Stages 1-4 or Non-REM (NREM)

Answer 6

brain waves decreases in frequency and increases in amplitude as sleep progresses through the four stages.

Question 7

REM Sleep

Answer 7

• REM sleep: a stage of sleep characterized by quickening brain waves, inhibited body movement, and rapid eye movements.
• brain waves increases in frequency and decreases in amplitude (the same level as when we are awake), despite being asleep.
• affects our ability to learn and is extremely important.
• lack of REM sleep can impair ability to learn.

Question 8

Sleep Cycle

Answer 8

• go through the 4 stages of sleep into REM, then go through 4 stages again.
• happens multiple times throughout the night.
• the duration of REM increases with each cycle.

Question 9

Restore and Repair | Theory of Sleep

Answer 9

the idea that the body needs to restore energy levels and repair any wave and tear experienced during the day’s activity.

Question 10

Preserve and Protect Hypothesis | Theories of Sleep

Answer 10

suggests that two more adaptive functions of sleep are preserving energy and protecting the organism from harm.

Question 11

Sleep Deprivation

Answer 11

• occurs when an individual cannot or does not sleep.
• can cause multiple impairments including difficulties with multitasking, maintaining attention for long periods of time and assessing risk.

Question 12

Sleep Displacement

Answer 12

• occurs when an individual is prevented from sleeping at the normal time although she may be able to sleep earlier or later in the day than usual.
• e.g. jet lag and daylight savings

Question 13

Freud’s Theory of Dreaming

Answer 13

• dreams represented our desires.
• two forms of imagery in dreams:
  
  • manifest content: involves the images and storylines that we dream about.
  • latent content: the actual symbolic meaning of a dream built on suppressed sexual or aggressive urges.

Question 14

Activation-Synthesis Hypothesis

Answer 14

• suggests that dreams arise from brain activity originating from bursts of excitation messages from the pons (a part of the brain stem).
• imagine having a dozen different people each provide you with one randomly selected word, with your task being to organize these words to look like a single message; this is essentially what your cortex is doing every time you dream.

Question 15

Insomnia

Answer 15

• a disorder characterized by an extreme lack of sleep.
• different types of insomnia:
  
  • onset insomnia: when a person has difficulty falling asleep (30 minutes or more).
  • maintenance insomnia: when an individual cannot easily return to sleep after waking in the night.
  • terminal insomnia or early morning insomnia: a situation in which a person wakes up too early (sometimes hours too early) and cannot return to sleep.
• for a sleep disorder to be labelled insomnia, the cause of lack of sleep must be internal (i.e. trying to sleep in a loud environment does not count).
• secondary insomnia: insomnia caused by depression, pain, too much caffeine etc.
• insomnia disorder: insomnia in which insomnia is the only symptom and all other causes are ruled out.

Question 16

Nightmares and Night Terrors

Answer 16

• nightmares: particularly vivid and disturbing dreams that occur during REM sleep.
• night terrors: intense bouts of panic and arousal that awaken the individual, typically in a heightened emotional state.
  
  • a person experiencing a night terror may call out or scream, fight back against imaginary attackers, or leap from the bed and start to flee before waking up.

Question 17

Restless Legs Syndrome and Somnambulism | Movement Disturbances

Answer 17

• restless legs syndrome: a persistent feeling of discomfort in the legs and the urge to continuously shift them into different positions.
  
  • is linked to the dopamine system and to an iron deficiency.
• somnambulism: (or sleepwalking) a disorder that involves wandering and performing other activities while asleep.
  
  • there are no medicine that treats sleepwalking.

Question 18

Sexomnia and REM Behaviour Disorder | Movement Disturbances

Answer 18

• sexomnia: a disorder in which individuals engage in sexual activity such as the touching of the self or others while in stages 3 and 4 sleep.
  
  • the cause is unknown although stress, fatigue, and a history of trauma are all possible factors
• REM behaviour disorder: a condition in which individuals act out the content of their dreams (unlike sleepwalking).
  
  • can be treated with medication such as benzodiazepines.

Question 19

Sleep Apnea

Answer 19

• sleep apnea: a disorder characterized by the temporary inability to breathe during sleep.
• prevalent amongst overweight and obese individuals.
• is usually caused by blockage to the airway but can also be caused by the brain’s failure to regulate breathing (this is more rare).

Question 20

Narcolepsy

Answer 20

• narcolepsy: a disorder in which a person experiences daytime sleepiness and even sleep attacks.
• medications are available to treat narcolepsy.

Question 21

Overcoming Sleep Problems

Answer 21

• practicing good sleep hygiene (healthy sleep-related habits) are the most beneficial.
• medication can also help but should be used as a last ditch effort.