Sleep and Dreams Midterm 1

lectures 1-3 plus mystery of sleep vid

Is Hibernation sleep

no because its seasonal not circadian

Most of what we know about sleep comes from studying

mammals

do animals all have the same sleep cycles?

no there are lots of differences between species in REM sleep

Phylogentic Order

refers to the arrangement of organisms based on their evolutionary relationships, often depicted through phylogenetic trees that illustrate common ancestry

NOT associated with sleep parameters 

Altrical vs Precocious 

altrical species (animals that need help after being born, need their parents) need more REM rather than precocious species

What is the primary function of non-REM sleep in relation to energy use?

Non-REM sleep is associated with reduced energy expenditure and a lower metabolic rate.

How does non-REM sleep affect metabolic rate?

It lowers metabolic rate, contributing to overall energy conservation during sleep.

Is REM proportional to brain size?

no

Do mammals have REM and non-REM?

all mammals experience both REM and non-REM

-maybe not cetaceans (Dolphins or whales) 

-relative proportion of REM and non-REM differs across species 

-general characteristics very similar across species 

-egg-laying originally thought to not have REM, but they do

Only non-mammals to have REM and non-REM

Birds

REM and slow wave sleep homeostatically regulated as in mammals 

-Song birds have more REM, increased REM following new song

No evidence of REM

Reptiles, Amphibians and Fish

EEG differ from mammals ands birds

-sleep behavuiour has large spikes in EEG
-spikes increase after sleep deprivation

-lack slow waves 

-no evidence of REM

Topor

a passive state in which insects enter

Does sleep change over lifespan?

yes, drastically

Sleep in Utero

-entirely in REM, brains develop

-more than half of first year of life is sleep

non rem is stable until about age of

10

REM is reduced at age ____ (again)

60

3 Types of sleep

1. Quiet sleep (QS, like slow wave sleep (SWS))

2. Active sleep (AS, like REM)

3. intermediate sleep (IS)

____ and ____ alternate in a 90 min cycle (50-60 for newborns)

QS and AS (quiet and REM sleep)

2 types of wake

1. quiet-wake, resting and really drowsy 

2. Active wake 

Babies sleep ____ and their sleep wave cycle is

16-18 hours

sleep wave cycle is 3-4hrs, goes with feeding times 

For Babies, active sleep becomes REM

after about 12 weeks

By age __ sleep is similar to adults but a little bit longer

10

Adolescent sleep

-teens need closer to 9-11 hours 

-most only get 6-7

=chronic sleep debt 

-things are made worse by going to bed late and waking late

Adult Sleep

-cycle 90-110 min

Light sleep on average 55%

-SWS on average 20%

-REM on average 25%

Senior Sleep

-sleep becomes fragmented 

-50% of seniors, naps reappear 

-longer sleep onset latencies (longer time falling asleep)

-nocturnal awakenings are more frequent and longer

-mild reduced total sleep time across 24 hr cycle 

-shorter first non-rem Rem cycle 

-sleep efficiency goes from 96% downwards (quality gets worse)

Delta activity occurs

in stage 3 sleep

As you age time spent in stage __ increases, why?

stage 1

less REM, more lighter stages of sleep

Stage 2 in adulthood

goes down in earlier adulthood, than increases again into older years

Time spent in stage 3 sleep

age 35, sws goes down in males, but higher in females as they age

Sleep efficiency reduces..

to 96% as children and then to 80% as senior

Waves when awake are called

alpha waves

Waves in each sleep stage

1. theta waves 

2. sleep spindles and k-complex

3. (slow wave sleep) delta waves

Sleep spindles

little burst of movement 12-16hz

k-complex

still dont know 100% what they do..

but theyre a negative reflection after a positive. Wave spikes up then drops down

Histograph

shows sleep stages

Most of deep sleep occurs

Most of REM occurs

Most of deep sleep occurs during first half of night.

Most of deep sleep occurs in second half of the night. After first two sleep cycles, REM periods get longer. 

Sleep is measured through, what system helps measures where to place the electrodes

electroncephalography (EEG) -on a cap thing

10/20 system, tells you measurements from center of the head

polysomnography (PSG) - what does that look like/contain? 

what is usually done at a sleep test

sensor on nose to measure air flow

sensors on face/scalp measures eye movements and brain activity

elastic belt sensors on chest and belly measures amount of effort to breath

sensor on finger -blood oxygen

wires transmit data to computer

Characteristics of LS (long sleepers)

introverted + depressed

some neurotic traits, some self-confidence problems, anxiety, more bodily aches

-prolonged sleep duration may be associated with an increased risk of dementia 

Characteristics of SS (short sleepers)

Extraverted, energetic/aggressive

-more conforming, denial of problems, abitious, decisive and out-going

3 aspects of sleepiness

1. Introspective

2. physiological

3. manifest

Introspective aspect of sleepiness and how it is measured

is the self assessment of your internal state. -how sleepy are you?

measured with scales such as:

-Epworth sleepiness scale (trait) stable and enduring

-stanford sleepiness scale (state) and temp and contex dependent

-various analog scales

Physiological aspect of sleepiness and how it is measured

is your body’s biological need to sleep (like hunger and thirst) using things like eeg

measured by the multiple sleep latency test (MSLT)

Manifest aspect of sleepiness and how it is measured 

is the behavioural component as shown in performance deficits, errors, inattention, and even being overcome by sleep. 

measured by maintenance of wakefulness test (MWT) -psychomotor vigilance task 

Factors influencing sleep positions 

body temp

ambiant temp

body type (size)

physiological conditions

laterality (left or right handed)

Daily activity level

surface of your bed

Kleitman

1952 decided to start charting eye movement in sleep at uni of Chicago, passed along his work later

REM= dream periods

Describe the average Sleep cycle

Muscles start to relax, brainwaves become slower

after ~ 80 min REM occurs and we dream for ~10 min

Another cycle follows, this time with ~20min REM

In next 90 min cycles we descend only to stage 2 (lighter sleep) but REM periods lengthen each time. 

in 7-8 hours should have ~4-5 REM cycles

During REM

Rapid eye movement

Dream state

Active paralyses of all our muscles (this is not relaxation)(except to breath) and for men, penile erection during REM. 

brain is more active during REM than when awake. 

Nightmares

Normal paralyses of REM gives way to the intensity of the nightmare

Various kinds of sleep disorders known as

Parasomnias

-abnormal behaviour between wakefulness and non-REM 

Suprachiasmatic Nucleus

-20,000 neurons form a biological clock that influences wakefullness

rhythm of rising and setting sun

circadian rhythm