9. Neural Bases of Sleep, Sleep disorders

not covering sleep disorders, focus on narcolespy

Sleep deprivation and main effects

partial or total loss of sleep

effects would be irritability, poor attention and working memory

episodic disorientation and hallucinations and psychosis during prolonged deprivation

health consequences of sleep deprivation

if you deprive yourself of sleep deprivation for a long time, it will worsen your immunity, and increase risk of obesity, diabetes, and heart disease (because sleep needed for repair)

Fatal familial insomnia

ireversible disease because misfolded proteins, create more misfolding.

once sleep trouble starts they die a couple months, to years after. 7-24 months

autopsy shows they lose gray matter

Sleep recovery

compensatory sleep that is longer than normal after a period of sleep deprivation

Sleep recovery example: Randy Gardener

this high schooler doing a study for his science class, went 11 days without sleep.

EEG findings showed that first night he went back to sleep had more time in Non-REM 3 sleep (slow wave)

also people who sleep 5-6hrs / night tend to have more SWS

SWS is prioritized when you dont get enough rest

REM Deprivation study

by depriving someone of REM sleep stage.

Preventing REM, made patient enter into REM very quickly and more often. The amount of times they would near REM in a night toward end of study was 70x

afterward they went through REM rebound. pritoized if deprived

REM rebound

sleeping at REM stage for longer, after REM deprivation

Sleep recovery studies overall findings and implications

when sleeping after sleep deprivation we don’t recover as much sleep as we initially lost. (gardener didn’t go sleep for 11 days)

the body is selective: prioritizing certain stages of sleep if they were specifically deprived

implications:

NREM3 and REM are more important than other stages

being separately regulated hints that they serve different functions (physical, cognitive)

what are the Neural regions for sleep? BBPH

Basal Forebrain

Brainstem (reticular formation)

Pons

Hypothalamus

Basal forebrain (function, mechanism)

solely responsible for SWS and REM. we know this because electrically stimulating this area makes animals sleep, and lesions create insomnia

how: releases GABA neurons into hypothalamus’s tubermammillary nucleus

Brainstem (rectivular formation) (function, mechanism)

will stimulate the forebrain to the wake body. we know because electrically stimulating this region will lead to awakeness, alertness and leisions will cause constant sleeping

how: brainstem has acending arousal system: loose network of neurons: monoaminergic axons that project to the thalamus

Pons = REM (function, how)

keeps REM sleep going, and relaxes muscles (atonia) we know because lesioning will stop atonia, but REM keeps going

how:

subcoeruleus signals for REM sleep.

Medullary axons projecting to spinal cord inhibit motor neurons from firing, causing muscle atonia:

glutaminergic neurons release GABA to inhibt spinal motor neurons

Hypothalamus (sleep)

as the control center it modulates the forebrain, brainstem, and pons to integrate transitions between sleep-week

how:

has neurons that use hypocretin as NT
hypothalamus transmits axons to other sleep regions, and coordinates them.

lacking Hypocretin will lead to uncoordinated, disorganized sleep. ex. muscle atonia when awake

General Anesthetics (function)

makes person unconscious, because they are agonists to GABA receptors they lead to Slow wave sleep

Gaba function, examples of agonists and mechanism

is a ionotropic recpetor which when binded to will inhibit the excitation of neurons, and sedate

(ex. benzodiazepine, barbiturates, and ethanol)

allows Cl - to pass through, hyperpolarizes

will isolated brain: cut spinal cord (behind pons, and infront, still allow sleep?

Yes, because we don’t need input from spinal cord to sleep, that signal comes from forebrain

but cut infront: you divide the forebrain from brainstem, and isolating it would cause constant sleep. other regions cant signal it to stop there. need interactions

Narcolepsy (+ relation to REM, Cataplexy)

sleep attacks, and feel tired during the day.

immediately enters REM after falling asleep

may have sudden muscle atonia called cataplexy. triggered by intense emotions: laughter, anger (limbic activation)

Hypocretin

peptide in the hypothalamus. lacking this peptide is associated with narcolepsy. neurons making this peptide project to all sleep regions of brain plus tubermammillary nucleus. they stablize the system and help wake to sleep transisitons

Melatonin (function, how)

syncs sleep-wake cycles with light and dark cues

helps sleep by signals to body that it is nightime: controlling arousal.

when light eyes → SCN hypothalamus _> signal to pineal gland suppress melatonin release

when dark no inhibition, melatonin secretion increases

Chronotypes

individual difference for preferred times to be asleep and awake.

age, gender, and varitions in clock, cycle gene leads to individual preferences

it is on a spectrum. true early birds, and night owls are on far ends

Ciradian shift in Adolescence

once teenage hood hits until 20 people tend to need sleep longer. more like to be owls

more so for males

stops for women after menopause

Social jet lack (what, why, fix?)

when your natural sleep preference and imposed sleep schedule are mismatched.

we get jet lack most on Mondays because through weekdays we follow forced times, are free on weekends and readjust back on monday

leads to less attention, fatigue, worse performance, increased mental health, and metabolic risks

fix: keep consistent schedule everyday

Sleeping pills (how, effects)

usually benzodiazepine, bind to and thus increase frequency of opening GABA receptors, activation.

increase use will lead to tolerance

distort normal sleeping pattern

drowsiness, memory gaps

insomnia when stop using

Caffeine recap, rebound effect

antagonist to adenosine receptors. preventing sleepiness

rebound effect: adenosine is made continously so when ceffeine wears off it binds and you get more tired

Naps (function, effects, when to nap, duration for NREM 1, 2, 3.

relieve sleep pressure (need for sleep)\

counteracts neg effects of deprivation boost alertness, performance, mood

time it at noon so not disrupting nighttime sleep

10-30: NREM 1 , NREM 2

long: NREM 3, waking up from it causes grogginess

Sleep hygines (name good habits)

habits for healthy sleep

stick to schedule, limit naps

follow a bedtime routine to wind down

have healthy habits: sunlight, no caffeine at night, no alcohol, exercise, only sleep in bed

make ur sleep physically comfortable

track how much sleep you get

Insomnia

difficult tiem falling or staying asleep

two types:

sleep-onset insomnia

sleep maintance insomnia

Paradoxical insomnia

sleep-onset insomnia

cant fall asleep

sleep maintance insomnia

cant say asleep

Paradoxical insomnia

mispercieves they are not sleeping, when EEG shows sleep just less SWS

insomnia ironic process of mental control

worrying about it, sensitivity to signs of sleep, stops it from working effectively

nightmares vs terror

nightmares are dreams happen during REM sleep

night terrors are during NREM sleep during 3 usually SWS: common in children, very arousing

somnabulism

sleep walking: can get dangerous ex. cooking, driving

REM behaviour disorder

acting out dreams. starts after 50 followed by parkinson’s, dementia

sleep apnea

cant breathe while you sleep