Exam 3: Sleep Pt 3

Question 1

sleep is an active state mediated by

Answer 1

• a forebrain system: generates SWS
• brainstem system: activates forebrain to wakefulness
• pontine system (pons): triggers REM sleep
• hypothalamic system : coordinates the other 3 systems

Question 2

melatonin is produced by ___ in response to___

Answer 2

produced by pineal gland

in response to changes in light

Question 3

light exposure to retina is relayed by ____ and inhibits ____

Answer 3

relayed by SCN

inhibits melatonin secretion

Question 4

melatonin secretion is suppressed by

Answer 4

bright light and hence levels increase during the night

Question 5

what do neurons use as their source of fuel

Answer 5

glucose

Question 6

when neurons run out of glucose what do they look to?

Answer 6

astrocytes

- provide additional glucose by mobilizing glycogen from storage

Question 7

what does the process of neurons needing astrocytes since no glucose produce?

Answer 7

adenosine - inhibitory neuromodulator

Question 8

accumulation of adenosine increases…

Answer 8

delta waves

Question 9

caffeine

Answer 9

adenosine antagonist

- blocks sleep signals from binding to receptors

Question 10

acetylcholine system: where are cell bodies located? where do the axons project to?

Answer 10

• cell bodies in basal forebrain and pons (PPN)

axons project to : cerebral cortex and brainstem

Question 11

activation of Ach neurons produces behavioral activation and ____

Answer 11

cortical dysynchrony

Question 12

high Ach during __ and __

Answer 12

wakefulness and REM sleep

Question 13

Ach agonists vs Ach antagonists

Answer 13

Ach agonists: inc arousal

Ach antagonists: dec arousal

Question 14

Norepinephrine neurons in ___ show high activity in wakefulness and low activity in sleep - zero in REM sleep

Answer 14

Locus Coeruleus (LC)

Question 15

LC neurons play role in…

Answer 15

vigilance

Question 16

Raphe nuclei in ____ wake up forebrain

Answer 16

reticular formation

Question 17

electrical stimulation vs lesions to forebrain

Answer 17

electrical: wakes up animals
lesions: produces persistent sleep

Question 18

serotonin may suppress what?

Answer 18

processing of sensory information preventing reactions that may disrupt ongoing activities

Question 19

depression

Answer 19

low serotonin levels - extreme fatigue - not enough serotonin to keep you aroused

Question 20

histamine cell bodies are located…

Answer 20

in tuberomammillary nucleus of the hypothalamus

Question 21

where do histamine axons project to?

Answer 21

cerebellum, thalamus, basal ganglia, basal forebrain, hypothalamus

Question 22

cortical projections histamine

Answer 22

direct increase in cortical activation and arousal

basal forebrain projections- indirect through Ach-ergic neurons

Question 23

antihistamines

Answer 23

cause drowsiness as a side effect

Question 24

orexin

Answer 24

neuropeptide

aka hypocretin

Question 25

where are the cell bodies of orexin located

Answer 25

lateral hypothalamus

Question 26

where do the axons of orexin project to?

Answer 26

- basal forebrain, raphe nuclei, tuberomamillary nuclues | - strongly excite cholinergic, NE, serotonergic, dopaminergic, histaminergic systems

Question 27

what does orexin promote and prevent

Answer 27

promote: wakefulness inhibits: REM sleep prevents: transition from wakefulness directly into REM sleep

Question 28

narcolepsy

Answer 28

degeneration of orexin neurons - or low release of orexin when they should be awake they randomly fall asleep - struggle to stay alert

Question 29

flip-flop circuit for sleep

Answer 29

results in sleep OR wakefulness - not both at same time | - brain regions responsible for sleep and awake states are mutually inhibitory

Question 30

main sleep controller

Answer 30

ventrolateral preoptic area (VLPA)

Question 31

group of GABA neurons in hypothalamus

Answer 31

VLPA

Question 32

what does activity in the VLPA suppress and promote?

Answer 32

suppress: alertness and arousal promotes: sleep - inc activity during sleep - dec activity during wakefulness

Question 33

the constant SWS activity in the forebrain is generated by...

Answer 33

basal forebrain | - activated at onset of sleep, suppresses tuberomamillary nucleus

Question 34

neurons in the basal forebrain become active at sleep onset and release ______ which suppresses activity in the nearby _____

Answer 34

GABA | tuberomamillary nucleus

Question 35

what activates the cortex

Answer 35

reticular formation in the brainstem

Question 36

stimulation vs lesions to the reticular formation

Answer 36

stimulation: wakes up sleeping animals lesions: produce persistent sleep

Question 37

what does the reticular formation increase in arousal systems

Answer 37

norepinephrine, serotonin, histamine

Question 38

what do the basal forebrain and reticular formation seem to guide the brain through

Answer 38

SWS and wakefulness

Question 39

the VLPA and major wakefulness promoting regions are reciprocally connected by ...

Answer 39

inhibitory GABAergic neurons

Question 40

when the flip flop is in "wake" state arousal systems are ___ and VLPA is ____

Answer 40

active | inhibited

Question 41

when flip flop is in "sleep" state VLPA is ____ and arousal systems are ____

Answer 41

active | inhibited

Question 42

what does adenosine buildup disinhibit?

Answer 42

VLPA

Question 43

adenosine increases sleep pressure to shut down arousal which in turn turns on the ____

Answer 43

VLPA

Question 44

stabilize sleep/waking flip-flop through excitatory connections with wakefulness neurons

Answer 44

orexin neurons | - constant release of orexin when awake to lock in the aroused state

Question 45

what brain region triggers REM sleep

Answer 45

the subcoeruleus of the pons

Question 46

neurons of the subcoeruleus (3 things)

Answer 46

- only active in REM sleep - inhibit motor neurons to keep them from firing in REM sleep (sleep paralysis, do not move body) - lesions prevent loss of muscle tone in REM sleep (start to act out dreams in REM - sleep walking)