Sleep and the Circadian Rhythm

7/26/2019 Sleep and the Circadian Rhythm

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Sleep and theCircadian Rhythm


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Facts About Sleep

We spend around 25 years sleeping.All mammals, birds and reptiles sleepalthough only mammals and some birdshow RE sleep.

!ne theory suggests sleep is "or restorpurposes

!ne theory suggests sleep is "or e#olutadaptation.


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What is Sleep

2 types o" acti#ity during wa$e"ul state

%eta wa#es

& more common ' were characterised by low

amplitude and #ery irregular (desynchronised) wathat #aried between *+ and + cycles (-) or /beasecond.

& 1his pattern occurred when subects waroused, or engaged in some mental acti#ity


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What is Sleep

2 types o" acti#ity during wa$e"ul state

Alpha wa#es & . 3uring periods o" rest and rela4atwa#es slowed down ('*2 -) producing a moresynchronised /high&amplitude6 pattern


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What is Sleep

2 types o" acti#ity during sleep state

Slow wa#e sleep (SWS) & /beat0 was much slower that normally "ound during the awa$e state, and "distinct stages (stages *'7) could be distinguishe


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1heta wa#es (7

3elta wa#es (*

3elta wa#es compr

Alpha wa#es (


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What is Sleep

2 types o" acti#ity during sleep state

Rapid eye mo#ement (RE)

& identi:ed by EE; acti#ity that resembled more closely the type o" "ound during wa$ing.

& this type o" sleep was accompanied by eye mo#ements that coulddarting about under the eyelids

& occurs about


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Cyclarou

minsREminsRE

1ime

SWS


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Sleep across the li"e span


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Infant Ad

Sleep cycle * hour appro4.


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-igh amount o" RE sleep occurs in the :rst year

*sttheory RE sleep plays a role in the de#elopmthe ner#ous system

2ndtheory RE sleep is necessary "or the storagein"ormation in the brain to allow learning and memta$e place


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Sleep across the li"e spanmaturation of the s

normally occurs b

adolescence (6 8

Young adult

ld age

!mount of time sp

especially in "#"

gro$ older


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Sleep depri#ation

a change in beha#iour or decrease in per"ormancecaused by $eeping an indi#idual awa$e can be attto the lac$ o" sleep.

sleep depri#ation in humans has not been so easy

interpret, because it appears to ha#e relati#ely litconsistent eBect other than ma$e the person "eelsleepy.

Studies show that sleep depri#ation in humans do


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1his is the case o" eter 1ripp, a disc oc$ey who ato stay awa$e "or 2 hours as a publicity stunt

money "or charity. -e made radio broadcasts "rombooth in Dew or$0s 1imes Suare in "ull #iew o" thand was constantly attended in order to pre#ent -owe#er, it was only during the last days o" his dethat 1ripp began to e4perience diGculties. 1he :rst si

slurred speech "ollowed by night&time auditory halluand paranoia. %y the end o" his ordeal he belie#edwas being drugged and re"used to cooperate with hi(3ement *). -owe#er, it had ta$en about a weedepri#ation to produce these eBects.

Sleep depri#ation Case *


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1his is the case o" a *8&year&old college student3iego called Randy ;ardner, who, in *5, challeworld sleep depri#ation record o" 2> hours (* dahours), which was, at the time, the world recoGuinness Book of Records. ;ardner was constantly scrutiny o" two obser#ers and, "or the last :#e closely "ollowed by William 3ement and ;eorge"rom Stan"ord =ni#ersity. 3uring his attempt,e4perienced a number o" diGculties includingirritability and memory problems.

Sleep depri#ation Case 2


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%y the se#enth day his EE; no longer showed tpatterns o" alpha wa#es associated with being awthese symptoms showed considerable Huctuation ' alast night he went to an amusement arcade "or se#where he played William 3ement at a penny bas$et(about * games were played) and won e#ery sinA"ter brea$ing the world record, ;ardner ga#e a cohimpeccable account o" himsel" at a national press co

Sleep depri#ation Case 2


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Sleep depri#ation

Case * and 2 shows that the main eBect appears the per"ormance o" comple4 mental or physiologitas$s reuiring a steady degree o" concentration.

1he results "rom these studies do not pro#ide con

e#idence that sleep is a #ital process.


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%rain mechanisms o" sleep

1he main area o" thebrain responsible "orthe production o"sleep is located in thebrain stem

speci:cally in thereticular "ormation#ia a pathway o"a4ons called theascending reticular

acti#ating system.


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in%ol%ed in a $ide

range of functions,including autonomic

acti%ity, motor

refle&es and sensory

analysis, and

recei%es input from

many other brain

structures


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laterodorsaltegmental nu(I1D) and the

pedunclopontegmental nu(1D)

' recei%e

cholinergic p

from + an

thereby prod

REM sleep


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site of noradrenaline.co

site of serotoninfibres

hibition o" cholinergic neurons in the I1D and 1D produces SW


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stimulation oregion produpatterns o" sacti#ity

recei#es in"othe stomach,duodenum aand this maye4plain why o"ten "acilitat


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Reciprocal odel o" RE Sleep

;1FI1D and 1D

Raphe Duclei andIateral Coeruleus

SWSSleep

DS1


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Circadian Rhythms

-

Jnternal mechanisms that "unctions as a Kcycle6 physiological and biochemical acti#ity

- Dearly all li"e"orms has one "orm o" circadian rhy

Early in thee#ening(growth

hormone)

Iate in thee#ening

(melatonin)

Wa$ing time in themorning

(cortisol and

Iate in thea"ternoon

(adrenaline)


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Deural basis "or circadian rhyth

1hree properties "or a

circadian pacema$er

*. it recei#es in"ormation "romthe senses (particularlyhelp"ul would be #isual

in"ormation concerning dayand night) to account "or the"act that circadian rhythmscan be reset byzeitbegers

Leitbegers ' stimuli that are regulators o" circadian rhythms (e4. light and dar$)

?


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circadian pacema$er

2. it has an intrinsicrhythm o" its own so

circadian rhythms can be"ree&running ?


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circadian pacema$er

+. it has output to otherregions o" the brain that

are in#ol#ed in circadiantypes o" beha#iour, suchas the sleep'wa$e cycle.

?


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Suprachiasmatic nucleus (SCD)- Circadian pacema$er in humans

- 3isco#ered in *


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!pticner#e

SCRetinohypothalamic tract

& J" lesioned, it is "ound that light and dar$ cueslonger able to reset the circadian /cloc$0, althouanimals still ha#e normal #ision


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1he most importantpathway is to thepineal gland!& Secretes the hormonemelatonin

& Controlled by a pathwaycalled the superior cervicalganglion


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SCD insuperior cervical ganglion

3ARNDESS

Onoradrenaline ineal cells (serotonin) melaton

D & acetyltrans"erase OIight terminates t


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Sleep & Wa$e disordersO

- encompass * disorders or disorder groups

E4.

insomnia disorder, hypersomnolence disorder, narcolbreathing&related sleep disorders, circadian rhythm swa$e disorders, non&rapid eye mo#ement (DRE) slearousal disorders, nightmare disorder, rapid eye mo#

(RE) sleep beha#ior disorder, restless legs syndromsubstance?medication&induced sleep disorder.

& o"ten accompanied by depression, an4iety, and cogniti#ethat must be addressed in treatment planning and manag


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Sleep & Wa$e disorders

InsomniaDisorder (DSM 5 "#5$% I&D '" )

- dissatis"action with sleep uantity or uality with como" diGculty initiating or maintaining sleep.

- Accompanied by clinically signi:cant distress or impasocial, occupational, or other important areas o" "unct

-

may occur during the course o" another mental disordmedical condition, or it may occur independently

- the most pre#alent o" all sleep disorders and most "reobser#ed as a comorbid condition with another mediccondition or mental disorder (7 ' 59)


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+arcolepsy (DSM 5 ,)#""- #"'- #'"% I&D '" )#)''-

)$.*

- recurrent daytime naps or lapses into sleep. Sleepiness typicadaily but must occur at a minimum three times a wee$ "or at lmonths (Criterion A).

- generally produces cataple4y, which most commonly presentsepisodes (seconds to minutes) o" sudden, bilateral loss o" mus

precipitated by emotions, typically laughing and o$ing.

- aBects .29&.79 o" the general population in most countrboth genders with a slight male preponderance

- can co&occur with bipolar, depressi#e, and an4iety disorders, acases with schiophrenia.


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/reat0ing Related Sleep Disorders

- %reathing disruptions during sleep

- obstructi#e sleep apnea hypopnea (3S ' 5 +28' * ;78.++)

- the most common breathing&related sleep disorder

- Central sleep apnea (3S ' 5 +28.2*, 8>.7, .5* ;78.+*, +8, R>.+)

- Sleep related hypo#entilation (3S ' 5 +28.27, .JC3 ' * ;78.+7, .+5. .+>)


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&ircadian R0yt0m Sleep 1a2e Disorders (3S +8.75)

- persistent or recurrent pattern o" sleep disruption tprimarily due to an alteration o" the circadian systea misalignment between the endogenous circadianand the sleep&wa$e schedule reuired by an indi#idphysical en#ironment or social or pro"essional sche

- 3elayed sleep phase type, Ad#anced sleep phase tJrregular sleep&wa$e type, Don&27&hour sleep&wa$eShi"t wor$ type

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Sleep and the Circadian Rhythm