Chapter 10 Biological Rhythms and Sleep

Biological rhythm that is about 24 hours long

Circadian

Biological rhythm that is less than 24 hours (can repeat many times during the day)

Ultradian

Biological rhythm that is longer than 24 hours

Infradian

Sleep/wake cycle is an example of what rhythm?

Circadian

Eating and hormone release are examples of what rhythm?

Ultradian

Menstrual cycle is an example of what rhythm?

Infradian

free-running rhythm

No external cues, maintaining own endogenous cycle

time between two similar points of successive cycles (like sunset to sunset)

Period

suprachiasmatic nucleus (SCN)

Master internal clock

Where is the SCN located?

hypothalamus

Entrainment

Shifting rhythm with external cues

Jet lag is the result of what?

Mismatch between internal and external time

zeitgeber (cue)

stimulus that entrains circadian rhythm

Special ganglion cells have a unique photopigment (melanopsin) that is sensitive to light and sends input to SCN

How light entrains rhythm

if someone lacks melanopsin, their circadian rhythms ___ __ _________

can be entrained

Rhythm is maintained _______ the body

outside

If lesion in SCN is present, what happens?

Internal clock is gone but external cues still present

Males are more likely to be _____ ____

night owls

___-_______ changes to circadian rhythm are present

age related

Synchrony

neurons firing together (low frequency, high amplitude)

Asynchrony

Neurons start in synchrony and then not (high frequency, low amplitude)

How many stages of sleep are there?

four

Stage 1 sleep

Asynchronous firing with little synchrony (low frequency, high amplitude)

What wave features are present in stage 1 sleep?

Alpha rhythms and vertex spikes

Stage 2 sleep

More synchrony with sleep spindles and K complexes

Stage 3 Sleep

Slow wave sleep (SWS)

SWS is said to be what type of sleep?

deep

Describe the neuronal firing during stage 3 sleep

Synchronous, high amplitude

What wave features are present in stage 3 sleep?

delta waves

REM sleep

Asynchrony, looks like someone who is awake/relaxed

Cerebral blood flow, neural firing rates, and temperature all increase (higher in REM than non-REM sleep)

What happens to brain during sleep

Heart rate and respiration are ______ in REM sleep compared to non-REM

Higher

While in REM sleep, postural tension and knee-jerk reflexes are __________

suppressed

While in REM sleep, there is an increase in ________ and _____ ___ _________

twitches, rapid eye movements

Hormone secretion during REM sleep is ___ while high in ___

low, SWS

Dreams are _____ during REM sleep and _____ during non-REM

vivid, vague

In the first 2 weeks of life, REM sleep accounts for how much of the infant's total sleep?

Half

Most people sleep ____ as they age, especially stage 3 sleep

Less stage 3 sleep can affect what?

physiology and cognition

Sleep deprivation behavioral effects vary by what?

age and personality

Irritability, difficulty in concentrating, and episodes of disorientation

most common behavioral changes from sleep deprivation

You never _______ all the sleep time you lost, but you may make up for the loss by having more intense sleep for a few nights

recover

the ______ you get to sleep, the ______ you recover

sooner

4 main functions of sleep

Energy conservation, niche adaptation, body and brain restoration, memory consolidation

Energy conservation

Use less energy when asleep

ecological niche

The unique assortment of environmental opportunities and

challenges to which each organism is adapted.

Niche adaptation

Fits each species' ecological niche, increasing chances of survival by avoiding predators and gathering food at better times

Body and brain restoration

deprivation increases risk factor for bad health outcomes - glymphatic system takes toxins out of brain

memory consolidation

SWS and REM sleep help memory formation, learning and recall

How many neural systems aid in the mechanism of sleep?

four

1st neural system

Forebrain system generates SWS

What can induce SWS activity in the basal forebrain?

Electrical stimulation

If the basal forebrain has lesions, what does it suppress?

sleep

Sleep active neurons in basal forebrain

become active at sleep onset

What is the main function of the forebrain system during sleep?

Gateway that helps turn the cortex up during waking and REM sleep, turns it down during deep sleep

2nd neural system

Brainstem system activates sleeping forebrain into wakefulness

Electrical stimulation of the brainstem does what?

activates forebrain, takes it out of SWS

Reticular formation

the activating system in brainstem

If the reticular formation is lesioned, what occurs?

persistent sleep (constant SWS)

3rd neural system

pontine system triggers REM sleep

the pontine system is called what?

REM sleep center, where some neurons are only active during REM

Function of pontine system

triggers REM sleep and prevents motor neurons from firing

Why is it important to prevent motor neurons from firing during sleep?

Muslces have no muscle tone (not just relaxed), cannot move during sleep

4th neural system

hypothalamic system coordinates the other three neural systems

Why does the hypothalamic system coordinate the other neural systems during sleep?

To know what stage we are in

What is the neuropeptide that is almost exclusively found in hypothalamus that is responsible for coordination and switching brain between the stages of sleep?

orexin/hypocretin

If orexin functions normally, what happens?

keeps sleep at bay and prevents direct transition from wakefulness into REM sleep

Narcolepsy

uncontrollable sleep attacks

Cataplexy

sudden loss of muscle control

trigger for cataplexy with narcolepsy

sudden, intense emotional stimuli

Cataplexy is the result of a loss of what?

orexin neurons

Insomnia

Problem of sleep quantity or continuity

Parasomnia

Abnormal behaviors or experiences that occur during sleep

Sleep state misperception

Sleeping without knowing

sleep apnea

unreliable respiration during sleep

How many non-REM related parasomnias were used as examples?

3

Night terrors

sudden arousals from SWS marked by intense fear and autonomic nervous system activation

Sleep enuresis

Bed wetting - associated with SWS, more common in children

What is a common treatment for Sleep enuresis?

nasal vasopressin (ADH)

Nasal vasopressin is given to those struggling with sleep enuresis because it does what?

increases water retention in kidneys

Somnambulism

Sleepwalking typically during SWS

How many REM related parasomnia examples were used?

two

Sleep paralysis

a temporary inability to move or talk just before falling asleep or just after waking

REM behavior disorder (RBD)

a sleep disorder in which a person physically acts out a dream

RBD occurs because of what?

muscle atonia of REM sleep is absent

Onset of RBD is followed by symptoms of what?

Parkinson's disease and dementia