Intro to sleep

Question 1

4 main needs that will result in death (indirect consequence) if we don’t have them?

Answer 1

sleeping
eating
drinking
breathing

Question 2

Total sleep deprivation is impossible to study because?

Answer 2

participants begin to microsleep = seem awake but brain waves suggest they’re asleep

SO, we largely focus on partial sleep deprivation

Question 3

Common themes in the definition of sleep

Answer 3

lack of consciousness/ temporary suspension of consciousness
naturally- occurring state
periodic and recurring
involves mind and body
relaxation and inactivity of muscles
–> sleep presents itself differently in different species, therefore, it is hard to find one definition that is applicable to all animals

Question 4

Humans
Dolphins
Bats
Giraffes

do all animals sleep?

Answer 4

sleep changes over lifespan
due to: hormonal changes/ changes in brain structure
eg. old people can’t initiate and maintain deep sleep

Dolphins - hemispheric sleep (Siegel, 2008)

bats - 18hrs sleep

giraffes - 2 hrs

• not all animals engage in sleep the way its defined (only v small number of species have been tested)
• may be more accurate to view sleep as a behaviour whose presence, quality, intensity and functions may vary between species and across the lifespan

Question 5

we spend 1/3 life sleeping, why?

Functions of sleep?- key theories?

Answer 5

repairing tissues
cell regeneration
repairing function
memory consolidation

Key theories
restoration - tissue/ muscle repair/ cognitive function
energy conservation
emotion regulation

Question 6

Factors affecting sleep?

Answer 6

anxiety
stress
sugar
phone screens

Question 7

Non-REM characteristics

Siegel, 2008

Answer 7

• greatly reduced activity in brainstem systems
• forebrain neuronal acitivty rates reduced
• high voltage slow waves and spindles presen in the neocortex (3+4)
• human brain consumes more than 20% of the body’s energy usage in quiet waking
• • > during NREM, forebrain metabolic activity is reduced far below this (reduction in brain metabolic rate can make a sig contribution in body’s overall energy consumption!)

Question 8

REM characteristics
(Siegel, 2008)

Answer 8

• pattern of discharge that closely resembles the waking brain in most regions
• brainsterm neurons highly active (exceeding rates of active brain)
• in many species REM brain is indistinguishable to the awake brain
• reduction in NORADRENERGIC = linked to muscle tone
• reduction in activity of HISTAMINERGIC = linked to loss of consciousness

Question 9

sensory response thresholds?

Siegel, 2008

Answer 9

during sleep we have a threshold that needs to be reached to wake us up
= explains why we wake up to baby crying but are unaware of household noises/ smells during sleep