Topic 1: Sleep and Dreams

Sleep apnea

A sleep disorder where you don’t breathe during your sleep because your throat is closed; you feel your chest heave up and down (paradoxical movement) and the belt can pick that up very well

Polysomnography (PSG)

A test conducted to diagnose sleep disorders. The test records your brain waves, the oxygen levels in your blood, your heart rate and your breathing. Also monitored are your eye and leg movements.

EEG

Brainwaves (Central & Occipital Leads)

EOG

Eye movements

EMG

Muscle tone, usually on the chin, picking up muscle movement

EKG/ECG

Heart rate

Airflow

Measured with a cannula (little tube) or thermistor (thermometer)

Breathing effort

Thoracic & Abdominal measurements

Digital AV recording

Taking infrared pictures of people to see what position they’re in; when people have apnea, usually they are sleeping on their back

10/20 system

Trying to standardize where electrodes should be on different sized heads; this system is based on how big their head is

N1 sleep

Lightest stage of sleep (hypnic jerks/sleep starts), dozing, very close to consciousness (ex. Falling dream and you wake up

N2 sleep

Sleep spindles & K complexes, has a lot to do with learning information and has a restorative aspect to it

N3 sleep

Deepest most physically restorative stage of sleep. More difficult to awaken from this stage. Decreases with age.

K complex

When the EEG does a huge upward spike followed by a huge downward spike and then becomes normal again; a reaction when your brain might need to wake up

Spindles

Thalamic activity that happens when you get a burst of activity that is much higher in frequency than the waves around it; often happens after K-complex

REM sleep

A sleep stage when your eyes move quickly and you dream, your brain is active, and your muscles are temporarily paralyzed.

Latency

How long it takes for something to happen (Ex. REM has a 90-minute ___)

Hartman

Studied people switching from SS to LS depending on stress level present; lots of stress= LS, less stress=SS (like normals but exaggerated)

Long sleeper

Get about 10-12 hours of sleep with a latency of 34 minutes and 110 minute-long cycle

Short sleeper

Get about 4-5 hours of sleep with a latency of 17 minutes and 90 minute-long cycle

Introspective methods

These are subjective methods, measured with scales such as: The Epworth Sleepiness Scale, The Stanford Sleepiness Scale, and The Analog Scale

Physiological methods

The Multiple Sleep Latency Test (MSLT)

Manifest methods

Maintenance of Wakefulness Test (MWT), Psychomotor Vigilance Task

Epworth Sleepiness Scale

0 = no chance of dozing, 1 = slight chance of dozing, 2 = moderate chance of dozing, 3 = high chance of dozing

Stanford sleepiness scale

Choose one of the following to describe your current state: (1) Feeling active and vital, alert, wide awake to (7) Almost in reverie, sleep onset soon, lost struggle to remain awake

Analog scales

Developed on which a person indicates how they feel by placing a mark on a line of set width, usually 10 cm, between very alert at one end and very sleepy at the other

The Multiple Sleep Latency Test (MSLT)

A formal study where the patient does a night study first and then the next day, they stay at the lab all day and go down to try to nap; commonly used to diagnose narcolepsy (will show REM during naps)

Maintenance of Wakefulness test

Same process as MSLT but you try to stay awake while semi-reclined

Psychomotor vigilance task

Reaction time to unpredictable visual cue; tests sustained vigilance in the face of monotonous task

Full-fetal position

Resistance to experiences and personality growth; highly emotional, sensitive, artistic; intense one-on-one relationships

semi-foetal position

Sensible adjustment to the world; well-balanced and secure; conciliatory, compromising, non-threatening, non-shakers (the personality of a “cotton ball”)

Prone position

Desire to control, take charge; don’t like surprises; strong compulsive tendencies, stubbornness in their personalities, persistent and goal-oriented

Dorsal position

Feel secure; assured; self-confident; strong personality; workaholic businessmen and entrepreneurs often prefer this position.

Johnson et al

First scientific study of sleep positions and found that most people prefer sleeping on their sides

De Konick

Found that as we are going into deeper sleep, we don’t tend to move, but as we come back up, we tend to move around

Chronobiology

The study of biological rhythms

Ultraradian rhythm

A biological rhythm that is more than once per day – they are ULTRA quick!)

Circadian rhythm

A biological rhythm that’s about 24hrs

Infradian rhythm

A biological rhythm that is less than once per day – multiple days IN a cycle

Period

Duration of the rhythm

Amplitude

Height of the wave

Acrophase

Time when the wave is the highest

Nadir

Time when the wave is at its lowest

Phase

Relative position of the curve relative to some other curve or to time (two curves can be in phase, or out of phase)

Seasonal affective disorder

Related to decrease in light exposure during the winter period. Can lower mood and alertness, and mess with phase advance/delay.

Growth hormone

Generally released at night, most prominent in children and released in SWS

Melatonin

Released on a 24 hour cycle, which triggers us to fall asleep; release is triggered by darkness

Physiological substrate

Hypothalamus: Suprachiasmatic nucleus (SCN)

Suprachiasmatic nucleus (SCN)

The conductor of our circadian rhythms; receives direct, non-visual light input from the retina

Phase delay

When a powerful light is present early during the subjective night, it delays the circadian rhythm (sleepiness happens later); more frequent in adolescents

Body temperature

Indirect measure of the circadian clock (Easier to fall asleep when ___ is going down)

Evening type (night owls)

Best functioning in evening, phase delayed, max vigilance at T acrophase

Morning type (morning larks)

Best at functioning in the morning, phase advanced, max vigilance 3 hrs before T acrophase

Pineal gland

Synthesizes and secretes melatonin, a structurally simple hormone that communicates information about environmental lighting to various parts of the body.

Circadian rhythm disorder

Lack of synchronicity between the endogenous rhythm and the external environment (phase advance or phase delay), leading to problems sleeping or staying awake, psychological problems, and cognitive problems

Phototherapy

Light = Powerful Temperature and melatonin synchronizer

Sleep-wake regulation model

There’s a « wave » in our sleep habits proving that certain times are better than others to go to bed

Core sleep

First 4 hours of the night, essential sleep you need to survive and keep your body relatively healthy

Optional sleep

Last hours of the night mostly made up of REM and stage 2 sleep and influenced by circadian rhythms

Homeostatic Process (S)

Is the expression of the tendency to sleep during the day and how deep sleep is during the night; depends on length of waking or of previous sleep

Circadian process (C)

Is the expression of our tendency or circadian need to sleep; dependent on our internal biological clock

Borbley’s model

This two-part model helps explain why sleep deprivation makes us need to regain some sleep, but not all of the lost sleep

Optic chiasm

The SCN is superior to this region, so it is able to give us light levels from above it

Forbidden zone of sleep

Between 6pm and 9pm; your body temperature is at its highest, so most people are alert in the evening

Sleep gate

Once you reached your maximum body temperature and it starts going down

Serotonin

A neurotransmitter that itself is derived from the amino acid tryptophan and is a precursor to melatonin

Phase advance

When a powerful light is present late during the subjective night, it advances the circadian rhythm (sleepiness happens sooner); more frequent in older adults

Zeitgeber

An environmental cue that helps us regulate and entrain our circadian rhythms (ex. light)