Psychology of sleep

What is the definition of sleep

a reversible behavioral state of low attention to the environment typically accompanied by a relaxed posture and minimal movements

How is sleep measured

Polysomnography, heart rate and breathing

What does EEG do

measures brain waves at the scalp

what does EOG do

measures eye movements

what does EMG do

measures muscle movements

What are the cons of polysomnogrpahy

expensive, difficult, inconvenient

how do we measure sleep in a more realistic way

actigraphy

what are the two types of sleep

REM and NREM

how long are sleep cycles

90 minutes

what are the functions of sleep

conserve energy, avoid predators, restore body’s resources, consolidate memories

In the 5th century Greece, what did Alcameon say

sleep was caused by blood filling the brain vessels and sleepers woke up when blood left their brain

What did plato and Aristotle believe

vapors from food decomposition in stomach rose to brain to cause sleep. when a person completed digestion, they woke up

in the 19th century (1830s) what did we believe about sleep

sleep is the intermediate state between wakefulness and death and sleep is something that just happens to us

Richard canon in 1875 discovered what

spontaneous electrical activity in the brain

Hans berger in the 1920s found what

activity could be recorded from the scalp (EEG)

Lord Adrian in 1930 found what

confirmation of the existence of spontaneous electrical activity in human brain

what created the halt on science and advancement

WW2

what did Nathaniel Kleitman do and when

set up first lab devoted solely to sleep research in 1920s

Wrote sleep and wakefulness - 1939

Discovered rapid eye movements - 1952

what happened in 1961

sleep research society formed

what happened in 1963

discovered that melatonin was synthesized in the pineal gland and responds to light

Who was William Dement mentor

Nathaniel Kleitman

Who is considered the data of sleep medicine

William Dement

who discovered and named the stages of sleep and when

William Dement in 1957

what was discovered in 1971

period gene is a component of the biological clock

what was discovered in 1972

the suprachiasmatic nucleus was the site of the biological clock

What happened in 1975

The second international congress of sleep research

the first international symposium on narcolepsy

American narcolepsy association formed

association of sleep disorder centers was organized

American academy of sleep medicine establlished

what happened in 1977

first exam to qualify for sleep specialist certification

what happened in 1978

first edition of sleep journal

what happened in 1979

ASDC diagnostic classification of sleep and arousal disorders published

project sleep

what happened in 1980

project sleep eliminated

Development use of multiple sleep latency test

what happened in 1990

National sleep foundation created

what happend in 1991

NSF conducted national poll

who is Mary carskadon

director at two sleep centers at brown university

developed the multiple sleep latency test

research and advocacy instrumental in delaying school start times

what happenedin the early 2000s

several drugs approved by FDA for treatments of narcolepsy and restless leg syndrome

what happened in 2005

the US national institute of health argued that cognitive behavioral therapy is the treatment of choice for insomnia

what happened in 2015

national sleep foundation released new recommendations for appropriate sleep durations (categorized by age group)

First issue of national sleep foundation’s journal

when was legislation passed for delayed school start times

2014-2023

when was the sunshine protection act introduced

2023

what is quiescent

a state or period of inactivity or dormancy

what is rest

a state of reduced activity without loss of consciousness or greatly reduced responsiveness

what is torpor

a state of decreased physical activity, usually marked by decreased body temperature and metabolic rate, may occur daily, easily aroused from this state

what is hibernation

a state of inactivity and metabolic depression, not easily aroused

what is the criteria of sleep

1. Rapidly reversible state of immobility

2. Greatly reduced sensory responsiveness

3. sleep is homeostatic ally regulated

4. Lost sleep is made up with an increased drive for sleep

5. Consequent sleep rebound

6. evolutionary problem: must be important and serve function to risk like to do it

what are the characteristics of sleep deprivation in humans

temps falls, gain weight, does not produce same autonomic changes as seen in other animals

the disc over water technique sleep deprivation in rats is characterized by

increased body temp and food intake, weight fell rapidly

Stereotyped pattern of fur discoloration and skin lesions

Body temperature eventually falls, death follows

does sleep occur in unicellular organisms

no

circadian rhythm activity is seen in what

cyanobacteria, protists, euglenozoa and dinoflagellates

do insects experience REM

no

what type of behaviors do cockroaches, bees, and scorpions have

quiescent

what insect had the criteria of sleep

fruit flies

what methods are used to measure sleep in a fruit fly

Actigraphy using an infrared beam, local field potentials, whole body calorimetry, intense stimuli, monitoring locomotor activity

describe sleep in zebrafish

circadian variations in responsiveness and activity, decreased response to stimuli after rest deprivation

describe sleep in perch

deprivation resulted in increase in rest behavior, light used for deprivation

what do frogs experience

torpor

do tree frogs experience REM

no

how to measure sleep in frogs

EEG

why is it that bullfrogs “dont sleep”

they are more responsive during periods of inactivity than when active

in reptiles, REM sleep exists how

absence of eye movement or muscle tone suppression

what do turtles experience

behavioral quiescence

do birds have REM or non-REM

both

describe sleep in white-crowned sparrow

sleep reduced by 2/3 during migration season, no reduction in accuracy or performance in tasks, no sleep rebound at the end of the period, no pathologies shown are seen in sleep-deprived rats

do land mammals sleep

yes

what is weird about African elephant sleep

in zoos: 4-5 hours per day with a low median lifespan

in the wild: 2 hours per day with long median lifespan

describe fur lion, sea lion sleep

on land: EEG bilaterally synched, cycles through REM and non-REM

In water: asymmetrical pattern of behavior, SWS in one hemisphere, contralateral eye closed, REM sleep time is reduced, little/no rebound when on land

describe sleep in bottlenose dolphins and beluga whale

show only unihemispheric slow waves, never show bilateral high-voltage waves, may float during while showing USW, but usually swim, circle in counterclockwise direction

Describe sleep in primates

Some apes show two sub phases in NREM. Consolidation of sleep into one or two long bouts. Reduction in total sleep time in diurnal primate species. Increased sleep intensity. Maintenance of social contact during sleep

What Neanderthals genes enhanced REM sleep

ASB1 EXOC6

What is the normal human sleep pattern

One consecutive period. Biphasic or bimodaL

When was references of biphasic sleep found

First century BC writings, Bible, medical books from 15th to 18th century

Describe two segments of sleep

First segment ~ dead sleep

Wakefulness at midnight ~ watch, watching, or first waking

Second segment ~ second sleep, morning sleep

How long were the segments of sleep

3.5 hours

Common wakefulness activities

Take medications

Study

Read

Tend to children

Crime

Prayer

When did sleep patterns begin to change

18th century

What helped nighttime activity increase

Improvement of oil lamps

Decline in magical beliefs

Shops stayed open

What are the hazards of the night

Cora, gas

Shift labor

Disruption of circadian rhythms

Why is the limbic system important

Important for motivation, emotion and memory- sleep and wake

What are the parts of the limbic system

Limbic cortex, hippocampus, amygdala, parts of the hypothalamus, portions of the frontal cortex

Parts of the limbic system

Medulla, pons,cerebellum, midbrain, reticular formation, raphe

What did Baron Constrain von Economo observe

Patients who had damage to their midbrain ~ diencephalic junction fell into a deeply sleepy state

Describe the conclusion of Frederic bremer

Severed cats spinal cord, just below brain and the cats were paralyzed

Severed cats spinal cord between superior and inferior colliculi cats were comatose

found that arousal influence must originate in the brain stem below the inferior colliculis

Basal forebrain is what

Key brain area to promote wakefulness

What is GABA do

Critical for maintaining wakefulness and high frequency EEG rhythms

Describe excitation of sleep promoting areas

Glutamatergic neurons in thalamus excite cerebral cortex

Describe inhibition of sleep promoting areas

GABAergic neurons inhibit the reticular nucleus of the thalamus and sleep promoting neurons in the pre optic area

What is acetylcholine and why important

Important for Arousal, wide projections to the cerebral cortex attention

Norepinephrine

Projections are widespread, NE neurons fire at higher rates during wakefulness, important for vigilance, enhances arousal

Glutamate

A primary neurotransmitter for arousal, plays role in producing brain waves seen in SWS

Histamine

Antihistamine induces drowsiness

Histamine cells project to ACh cells, increasing arousal

Orexin

Also referred to as hypocretin, role in switching between sleep states and appetite, widespread projection, only about 50-80,000 orexinergic neurons, excitatory effect on alertness, loss leads to narcolepsy

What is ARAS

Ascending reticular activating system, receives input from most of the sensory systems and forebrain

ACh producing neuronal groups located in PPT and LDT nuclei of the brain

Describe the route of ARAS

1. Output goes to a portion of the thalamus

2. Output goes to the posterior hypothalamus

Uses histamine to activate cerebral cortex

Output to basal Forbrain area, uses acetylcholine to excite cerebral cortex and hippocampus

How does the LC stimulate wakefulness

Uses norepinephrine to activate entire forebrain, sensory input control

How does raphe stimulate wakefulness

Uses serotonin to activate forebrain

How does additional brain stem areas promote wakefulness

Use dopamine to activate the forebrain

How does the lateral hypothalamus promote wakefulness

Neurons in this area produce orexin, orexin released from the ends of the axons to many other areas in the brain to facilitate wakefulness

Describe systems of sleep promoting neurons

Many are GABAergic

Primarily located in precipitation hypothalamus

Inhibitory control of Key arousal systems

What are the preoptic hypothalamus neurons

VLPO and MnPO

What does the VLPO do

Small group of cells in the anterior hypothalamus that become active at sleep onset, sensitive to sleep deprivation

What does MnPO do

Dynamically responsive to changes in homeostatic sleep pressure

What are paradoxical zone neurons

Group of sleep promoting neurons lateral and dorsal to facial nerve, show greatest increase in discharge prior to NREM sleep onset, may promote sleep via inhibit of lateral hypothalamus, basal forebrain and thalamus