Consciousness

Question 1

What are the 2 theories of consciousness?

Answer 1

• integrated information theory of consciousness
• global workspace theory of consciousness

Question 2

What is the integrated information theory of consciousness?

Answer 2

• consciousness can be described as different
• “levels”

Question 3

What is the global workspace theory of consciousness?

Answer 3

• changes in consciousness involve vigilance and wakefulness

Question 4

What is the default mode network (DMN)?

Answer 4

• brain is active even when not actively doing anything
• main parts of the DMN: Prefrontal cortex, posterior cingulate, angular gyrus

Question 5

What is sleep?

Answer 5

• sleep is a behavior, not the absence of behavior
• Bremer showed that it is a coordinated activity from the brainstem, not the absence of activity

Question 6

What are the functions of sleep?

Answer 6

• memory consolidation (REM)
• Song birds: playing their song during sleep leads to activity that matches them practicing their song
• activity in the hippocampus during REM
• amount of REM sleep increases after periods of training/learning

Question 7

What is another function of sleep?

Answer 7

• energy conservation (deep sleep)
• we sleep to conserve energy: species that sleep more tend to have higher metabolic rates
  ~ as we age, metabolism goes down-as does the amount of sleep

Question 8

What are the other proposed functions?

Answer 8

• Brain development in children/teens
• sleep may be a safe place to discharge emotions and relief from stresses
• possibly needed for physical health
• deep sleep = human growth

Question 9

What are the stages of sleep?

Answer 9

• slow wave sleep - stages 1-4
• REM sleep

Question 10

What are slow wave sleep stages 1-2?

Answer 10

• mostly alpha, beta, and theta waves
• K complexes in stage 2: response to environmental stimuli

Question 11

What are the slow wave sleep stages 3-4?

Answer 11

• mostly delta waves

Question 12

What waves are in REM sleep?

Answer 12

• beta and theta waves

Question 13

How do we progress through the stages at night?

Answer 13

• the first 4 hours contain more slow wave sleep
• the second 4 hours contain more REM
• REM episodes occur approximately every 90-120 minutes

Question 14

What brain structures involved in sleep?

Answer 14

• 2 main circuits involved in arousal
• 1) one is focused on sleep
• 2) one is focused on wakefulness: Suprachiasmatic Nucleus (SCN) appears to mediate between the two

Question 15

What are the 2 sleep structure?

Answer 15

Raphe Nuclei (pons) and gigantocellular tegmental field

Question 16

What does the Raphe Nuclei do?

Answer 16

• serotonergic network
• activity seems to be linked to slow wave sleep
• slow wave

Question 17

What does the Gigantocellular tegmental field?

Answer 17

• acetylcholine based
• activity linked to REM sleep
• originates PGO waves (ponto-geniculo-occipital) that occur with eye movements

Question 18

What does the high level structures do in sleep?

Answer 18

• preoptic area (hypothalamus)
• receives serotonin from raphe nuclei
• releases GABA to inhibit wakefulness structures
• initiate sleep

Question 19

What are the low level structures in wakefulness?

Answer 19

• locus coeruleus (pons): linked to norepinephrine network, activity linked to wakefulness

Question 20

What are the high level structures in wakefulness?

Answer 20

• postier hypothalamus: this is the area that is inhibited by the preoptic area that leads to sleep
• basal forebrain and thalamus likely also play a role in excitation of the cortical structures

Question 21

what processes that regulate when we sleep?

Answer 21

• circadian rhythms

Question 22

What does our circadian rhythm do?

Answer 22

• SCN is the likely center of circadian rhythms~retinohypothalamic tract sends info to it- allows for light to play a role
• transplants of SCN establish donor rhythms in recipient animals
  ~ bred hamsters with 20 hour rhythms; transferred into normal hamsters; shorter cycles ensued

Question 23

What is the SCN activity and light/dark cycles?

Answer 23

• the SCN is active during the day in both diurnal and nocturnal animals
• SCN seems to tell animals whether it is day or night, but not cause specific behaviors
• linked to the pineal gland~ secretes melatonin

Question 24

What are the geetic links to SCN?

Answer 24

• light triggers the fluctuation of some proteins
  increasing and decreasing various proteins lead to sleep/wake cycles

Question 25

What are the processes that regulate when we sleep?

Answer 25

• homeostasis debt: sleep pressure builds while you’re awake until you need to sleep, sleep pressure decreases while asleep
  ~ glycogen - ATP reserves/energy source
  ~ as the brain uses energy, ATP turns into adenosine
  ~ increased adenosine levels lead to slow wave sleep- adenosine inhibits wakefulness structures-glycogen levels build up during slow wave sleep

Question 26

What is insomnia?

Answer 26

• a sleep disorder
• usually treated with GABA agonists (Benzodiazepines) or melatonin agonists

Question 27

What is sleep apnea?

Answer 27

• a sleep disorder
• has obstructive vs central
  ~ obstructive = physical obstruction
  ~ central = brain signal issue

Question 28

What is narcolepsy?

Answer 28

• a sleep disorder
• excessive daytime sleepiness, cataplexy, paralysis, and hallucinations
  -enters REM at inappropriate times: both throughout the day and nighttime cycles

Question 29

What are the causes of narcolepsy?

Answer 29

• low hypocretin levels: possibly due to autoimmune issues
• genetic link to possible
• brain injuries to REM and wakefulness areas

Question 30

What are circadian rhythm’s disorders?

Answer 30

• they are issues when your SCN and the light/dark cycle in the environment don’t align
• advanced sleep-wake phase disorder: falls asleep too early and wakes up too early
• delayed sleep wake phase disorder: falls asleep and wakes up too late