Wk 8.1 Sleep and Wakefulness

Question 1

What is the definition of sleep?

Answer 1

unconscious state from which a person can be aroused by sensory or other stimuli(Perodic reversible state)

Question 2

What is the sleep epidemiology?

Answer 2

Ranks among the 3 important considerations in maintaining good health
Other two are:good nutrition stress management

62% of us population have sleeping problems

Question 3

What is the function of sleep?

Answer 3

• Allows body to return to equilibrium
• Restoration – recover and prepare for next awake session
• Adaptation – hide from predators when we are most vulnerable or to conserve energy.
• REM sleep has been shown to aid in consolidation of memories

Question 4

What does REM stand for and what happens during this stage?

Answer 4

Rapid Eye Movement Dreaming takes place

Question 5

What are the stages of sleep

Answer 5

Stage 1 - wake- relax but going to sleep

Stage 2 first stage of sleep, k complexes and spindles waves on EEG means the person is asleep

Stage 3- less thalamic activity, neurons firing together

Stage 4- deep stage, 30 mins to get to this stage

Question 6

What happens during deep sleep?

Answer 6

More the neurons are firing closer together

Bigger signal because the more the fire together, the more electrical waves

Question 7

How do you read sleep cycle EEG?

Answer 7

High frequency and low amplitude for wake
Low frequency and high amplitude - for asleep

Question 8

1.What is the % of sleep time in REM?
2. What happens in REM
3. What does REM cause
4. What does REM activate

Answer 8

1.Occupies 25% of total sleep time

2.Activity changes to REM approximately 4-5 times a night

3.Irregular heart rate and respiration

4.Melanin-concentrating neurons strongly active

Question 9

How is sleep measured?

Answer 9

Electroencephalogram (EEG) electrode - attached to scalp to get information from the cortex

Question 10

What regions are involved in sleep regulation?

Answer 10

Thalamus
Hypothalamus
Pineal gland
Locus Coeruleus
Dorsal raphe
An and po nucleus

Question 11

Information on vebtrolateral preoptic nucleus?

Answer 11

-Contain GABAergic andGalanergic neurons

-Reduce monoamine arousalsystem during sleep

-Monoamine neurons inhibit its neurons

Question 12

What are the two wakefulness pathways and what do they do?

Answer 12

-Acetylcholine Pathway Thalamocortical pathway= Activates thalamic relay neurons and reticular nucleus of thalamuscrucial for transmission of information to cerebral cortex

-Monoamine pathway Extrathalamic pathway = Activates neurons in the basal forebrain before activating cortex

Question 13

What are the 2 acetylochloine cell gorups

Answer 13

-Pedunculo-pontine (PPT)
- Laterodorsal tegmental nuclei(LDT

Question 14

What does monoaminergic neurons in the upper brainstem include.

Answer 14

• Locus ceruleus (NA)
• Raphe Nucleus (5HT) (dorsal andmedial)
• PAG and VTA (Dopamine)
• Tuberomamillary neurons(Histamine)- anti inhibits histamine leading to feeling sleepy

Question 15

Which pathway is highly activated in REM sleep?

Answer 15

Acetylcholine Pathway

Question 16

1.What is the flip flop sleep circuit?
2. How does it work?

Answer 16

1. Two halves strongly inhibit each other and produce on or off switch

2.If either side is damaged or weakened= instability occurs in both sleep andwake states.

• When monoamines fire rapidly during wakefulness they inhibit the VLPO.
• When VLPO neurons fire rapidly during sleep they inhibit the discharge of the monoamine groups

Question 17

What is the Regulation of sleep/wake cycles?

Answer 17

-Suprachiasmatic Nucleus of theHypothalamus = A Brain Clock

• 20,000 neurons and their circadian actibity is activated by light (Light is detected by eyes)

-Intact SCN produces rhythmic message:SCN cell firing rate varies with circadian rhythm

Question 18

How does glycogen and Adeosine work?

Answer 18

Glycogen broken down to adenosine (Increased through out the day)

Adenosine increase causes need to sleep so It activated the vetro-laterial preoptic nucleus, blocks one of the sleep pathway the basal pathway

Question 19

What does caffeine do to adeosine?

Answer 19

Caffeine blocks adeosine receptors and promotes alertness and arousal

Question 20

What are the types of sleep disorders?

Answer 20

Insomnia
Narcolepsy
Restless leg syndrome
Sleep apnoea

Question 21

What does insomia do?

Answer 21

Increase cerebal metabolism on PET
during sleep EEG - decreased delta and theta activity and increase in beta activity
Body temp is slighty higher

Question 22

What are the different types of Insomnia?

Answer 22

-Sleep onset insomnia=Difficulty sleeping and longer sleep onset

-Sleep maintenance insomnia= difficulty staying asleep and awaking up

-Sleep offset insomnia= waking up early

-Nonrestorative sleep=Fatigue despite good sleep duration

Question 23

What is Nacrolespy and key information?

Answer 23

-Neurological disorder- causes excessive daytime sleepiness

-Associated with Cataplexy

-Abdnormal REM sleep

-Neuronal loss of hypocretin neurons

Question 24

What is Restless leg syndrome?

Answer 24

-Urge to move legs during sleep (arms, trunk orhead may be affected

Question 25

What is sleep apnea?

Answer 25

Condition where the walls of throat relax and narrow and blocks breathing