Chronobilogy/ Sleep and Waking

Question 1

What is the order of the sleep cycle?

Answer 1

stage 1, stage 2, stage 3, stage 4, stage 3, stage 2, REM, stage 2 etc

Question 2

How do the sleep stages shift as the night goes on?

Answer 2

more REM sleep, less stage 4 sleep

Question 3

What waves are associated with awake EEG? awake but drowsy?

Answer 3

Beta waves

alpha waves

Question 4

What waves are associated with stage 1?

Answer 4

theta waves

Question 5

What waves are associated with stage 2?

Answer 5

theta waves and kappa waves, as well as sleep spindles

Question 6

What waves are associated with stage 3?

Answer 6

delta waves (20-50% of EEG)

Question 7

What waves are associated with stage 4?

Answer 7

delta waves (over 50%)

Question 8

What stage is restorative sleep?

Answer 8

stage 4

Question 9

What do REM waves look like?

Answer 9

look like awake waves, with sawtooth waves too sometimes

Question 10

What dominates in REM sleep? What NT is used for this tone to dominate?

Answer 10

sympathetic tone, brain uses NE to make brain more awake even though youre asleep

Question 11

How does sleep shift across the lifespan?

Answer 11

quantity of sleep decreases, lose stage 3 and 4 sleep

Question 12

What is melatonin produced by and in response to what stimulus?

Answer 12

produced by pineal gland with loss of light (uninhibition of pineal gland)

Question 13

What do the MT1 and MT2 receptors for melatonin do?

Answer 13

MT1- lowers brain activity and arousal by suppressing sympathetic drive and RAS
MT2- facilitates 24 hr circadian clock in the suprachiasmatic nucleus

Question 14

How does cortisol affect sleep?

Answer 14

it peaks in the morning to help awakening, links hypothalamic-pituitary axis to circadian system

Question 15

What chemicals are wakefulness chemicals? (6)

Answer 15

Ach, glu, NE, DA, 5HT, histamine

Question 16

What does the basal forebrain (BF) release?

Answer 16

Ach during wakefulness and sleep
GABA to inhibit inhibitory neurons in sleep promoting centers
(promotes wakefulness while lowering sleepiness)

Question 17

What does the laterodorsal and pedunculopontine tegmental nuclei (LDT/PPT) in the pons release?

Answer 17

Ach to promote wakefulness

Question 18

What does NE do? Where is it released from?

Answer 18

optimizes attention and task performance while awake, excessive firing causes insomnia and anxiety at night
released from LC

Question 19

How are blood pressure meds used to treat insomnia?

Answer 19

decrease sympathetic activation to lower effect of NE and lessen nightmares and anxiety

Question 20

What releases histamine?

Answer 20

tuberomamillary nucleus

Question 21

What does the H1 receptor do? H3?

Answer 21

H1- leads to wakefulness when stimulated

H3- autoreceptor that inhibits histamine activity to promote sleep

Question 22

What does stimulating H1 or blocking H3 cause?

Answer 22

wakefulness

Question 23

Where is serotonin (5HT) released from? What does it generally do?

Answer 23

dorsal raphe nucleus, promotes wakefulness and inhibits REM

Question 24

What is the circadian clock gene?

Answer 24

5HT 7

Question 25

Dopamine produced from the substantia nigra does what? from the ventral tegmental area? from the periaqueductal gray?

Answer 25

- SN--> promotes movement - VTA--> promotes reward - PAG--> wakefulness

Question 26

Is orexin part of the reticular activating system?

Answer 26

no, it runs parallel to it and stimulates it when it falters to sustain wakefulness

Question 27

Where is orexin made? What does it act on?

Answer 27

lateral hypothalamus, acts on LC and TMN

Question 28

What does the thalamus do in regulating wakefulness/sleep?

Answer 28

coordinates and gates the separate but interacting arousal systems, integrates the systems to spit out either glu or gaba to cortex

Question 29

Does RAS incrementally increase wakefulness chemicals or do so in an all or none fashion?

Answer 29

incrementally increases (acts like a light dimmer)

Question 30

What is the suprachiasmatic nucleus?

Answer 30

master switch for sleep/wakefulness, dampens TMN and RAS

Question 31

What does the orexin system act as?

Answer 31

backup generator if TMN or RAS falters

Question 32

What are TMN and VLPO? Do they act incrementally or in all or none fashion?

Answer 32

TMN- wake center, VLPO- sleep center | wake/sleep on/off switch, act in all or none fashion