Lecture 4-6 Flashcards
What is the restorative theory of sleep?
- rest, recuperation
- repair effects of daily wear & tear
- physiological processes restored
- growth hormone released from pituitary: increased cellular division & RNA synthesis
- REM: protein synthesis, increases after learning
- N3 taxed in learning
What is the memory consolidation & learning theory of sleep?
- consolidation & facilitation of long-term memory
- brain rehearses newly learned info in N3
- declarative/explicit memory = N3 needed
- nondeclarative/implicit memory = REM needed
What is declarative/explicit memory?
- conscious recall
- semantic (concepts, facts, landmarks) + episodic (experiences, events)
What is nondeclarative/implicit memory?
- unconscious recall
- procedures, how to’s, motor skills, habits (throwing a ball, learn to drive, recognise faces)
What is the adaptive, survival theory of sleep?
Sleep patterns due to:
- predator or prey
- when can see optimally
- caloric use:
- sleep = less calories, less food
- awake when food most available
- environment:
- prevent drowning, sinking, danger
- cerebral hemispheres “take turns”
- move to warmth/cold
- safe, preferred sleeping location
- integrated into annual cycles: hibernation, reproduction
What is the energy conservation theory of sleep?
small animals: high metabolic rate - sleep longer with shorter NREM-REM cycles
larger animals: slower metabolic rate - sleep less, longer NREM-REM cycles
What is sleep like in mammals, birds, reptiles, amphibians, fish & invertebrates?
- > 90 species of mammals studied
- closer to humans = more similarities
- all reptiles and birds exhibit N3 & REM but species dependent
What is a sleep feature in birds?
less REM than mammals, except predator birds
What is a sleep feature in owls, moles & opossums?
no eye movements
What is a sleep feature in dogs, wolves, rabbits & birds?
not complete REM paralysis, much eye movements
- phasic eye movement
What is a sleep feature in reptiles, tortoises & turtles?
high amplitude spikes during sleep
- is it sleep or cold blooded torpor (physical & mental inactivity)?
What is sleep like in sea dwelling or migratory animals?
- cannot “settle” to sleep, surface breathing, flying long distances
- bottlenose dolphins, porpoises, pigeons, mallard ducks
- asynchronous brain sleeping
- large sea mammals: hold breath and sleep for 30mins, wake to surface & return down
What is asynchronous brain sleeping?
- one cerebral hemisphere at at a time
- half-brain in N2-N3, while other awake with opp. eye open; one hour each side
What is sleep like in bears, caterpillars & frogs?
hibernation:
- extreme lowering of body temp, metabolic rate, respiration, with short periodic bouts of rise over several weeks
- no/little recordable EEG
hibernation complete:
- sleep for extended period with increase in N3
What is sleep like in fruit fly, marine snail, scorpions, cockroaches & jellyfish?
quiescence & activity
What is sleep like in infants?
- newborn brain immature to produce adult EEG wave patterns
- AS, QS, IS
- healthy newborn: 16-18hrs, >50% in AS
- late term or premature: >75-80% in AS
- enter AS right after falling asleep
- distribution of sleep-wake numerous in nychthemeron
- QS & AS alternate in 50min cycles, increasing in time till 5mths old
- AS = REM at 3mths; QS = N3 at 6mths
What is active sleep (AS)?
low-voltage, irregular EEG, eye movements, low-high EMG, no motor paralysis; first smile
What is quiet sleep (QS)?
EEG similar to adult N3, no eye movement, mid-lower EMG, absence of body movements
What is intermediate sleep (IS)?
mixture of quiet and active
What is a nychthemeron?
period of 24 consecutive hours
What is sleep like in early childhood?
- 2-3mths: able to sleep thru night, w/ daytime naps
- 3mths: 40-50% in REM
- 5mths: at least 50% of infants sleep when parents sleep
- 8mths: 33% in REM, sleep 13-14hrs
- between 1-2 years: REM stabilizes at 25%, same as young adult
- 3-5 yrs: sleep 10-13 hrs & daytime napping ceases
What is the theory for early childhood sleep?
REM important to neural/nervous system maturation; needs stimulation
What is sleep like in children?
- NREM-REM cycle: 60mins
- enter N3 quickly, stay for 1hr, then arousal-sleep EEG, skip first REM
- position changes
- first REM 10-20mins, w/ subsequent periods 20-25mins
- by 10yrs: cycles resemble adults, but sleep 10hrs
- pre-teen (12-13yrs): fall asleep quickly, v. deep N3, v. difficult to wake
What is sleep like in adolescence?
- need 9+hrs per nycthemeron
- obtain 6-8hrs (+ sleep in, weekends): signs of sleep debt & deprivation
- 25% in REM
- circadian phase delay to later sleep hours
- vs. school times & learning expectations