Sleep and EEGS

Question 1

What is sleep and how is different from a coma

Answer 1

Sleep :State of unconsciousness from which an individual can be aroused via stimuli of light, touch, perception.
Coma: state of unconsciousness from which an individual CANNOT be aroused through stimuli.

Question 2

What is sleeping due to?

How has this been verified?

Answer 2

Occurs due an inhibitory process which occurs in the pons- impulses must be send through down the mid-line of the pons (damage to this area leads to sleep deprivation)

Question 3

Which are the neurotrasmitters involved in controlling sleep activity?

Answer 3

Serotonin and melatonin

Question 4

Which impulses control sleep activity?

Answer 4

Neurones which are fired from the reticular formation of the midbrain

Question 5

Where are the impulses from the reticular formation sent to?

Answer 5

• The hypothalamus
• The thalamus
• The cortex

Question 6

What controls the circadian rhythm of electrical impulses

Answer 6

Hypothalamus and Superchiasmatic nuclei are also related to control of slee

Question 7

What does circadian mean?

Answer 7

It defines a group of patterns in the body which change over 24 hours

Question 8

What stimuli do the SCN respond to?

Answer 8

• Time zone changes
• Day/night
• Work patterns

Question 9

Where is the SCN located?

What does this implicate?

Answer 9

Located just above the optic chiasma so must receive info from the brain

Question 10

How does the sleep cycle work?

Answer 10

• Excitatory neurones are activated (from sleep centres in reticular formation) in the ascending reticular activating system (ARAS) of reticular formation
• These excitatory neurones release impulses which stimulate excitatory pathways in the CNS and PNS
• A positive feedback system allows these pathways to stay activated for a very long period of time
• These cells slowly become fatigued
• Peptides from the sleep centres oft reticular formation are released- dominate over excitatory pathways= lead to sleepiness

Question 11

How do people who are blind dream?

Answer 11

• If bind from birth have auditory dreams

- If they become blind- they will slowly lose their ability to dream in vision

Question 12

How do dolphins and birds dream?

Answer 12

One side of the brain awake, one asleep.

Question 13

What does EEG measure

Answer 13

ecords electrical patterns of the brain
Measures amplitude of waves (size of wave : from 0-200 microV)
Measures frequency of waves ( measures the number of waves in 1 second 0-50)

Question 14

Different EEGs based on state of consciousness

Answer 14

• Awake: high frequency, low amplitude

- Asleep: low frequency, high amplitude

Question 15

4 types of wave seen on an EEG

Answer 15

Alpha
Beta
Theta Gamma

Question 16

Alpha waves

Answer 16

High frequency, high amplitude
Wave synchronise with each so high amplitude
-Occur when alert but relaxes e.g. with eyes closed

Question 17

beta waves

Answer 17

High frequency, low amplitude
Low amplitude a result of more waves due to more stimuli
More waves- desynchronise (opposing polarities)
-Occur when very very alert

Question 18

Theta waves

Answer 18

Low frequency, various amplitude

-Occur in children, times of emotional stress, frustration and during sleep

Question 19

Delta waves

Answer 19

Low frequency, low amplitude

Question 20

Stages of sleep

Answer 20

5 stages
1-4
REM

Question 21

stage 1

Answer 21

• Light sleep, easily aroused
• Waves have long amplitude and low frequency
• Low frequency Theta waves
• NON-REM waves
• Slow eye movements

Question 22

Stage 2

Answer 22

• Eye movements stop
• Even slower frequency waves
• Small rapid bursts of waves = sleep spindles (12-14Hz)

Question 23

Stage 3

Answer 23

• Very slow (2Hz)

- spindle activity decrease but where present waves are faster

Question 24

Stage 4

Answer 24

-Only delta waves

Question 25

REM sleeping

Answer 25

- EEG is very similar to someone who is awake- known as paradoxical - 25% of sleep - When dreaming occurs

Question 26

Characters of deep sleep

Answer 26

- very very deep for the first few hours - Decrease in vascular tone (BP), decrease in respiratory and metabolic rate - Most restful - Some dreams can occur but not as many as REM

Question 27

Characters of REM

Answer 27

- Can last between 5-30 mins every 90 mins - Becomes more frequent as hours of sleep increase - Where most dreams occur - Rapid movements of eye- all other skeletal muscles are inhibited by signals sent from the pons to spinal cord (prevents acting out of dreams- absent In people who suffer from REM sleep behaviour disorder) - HR/ RR and metabolism increase- mimics waves of a person who is highly awake - Dependant on cholinergic patheways of reticular formation to hypothalamus/thalamus and cortex. REM sleep can be increased by use of anticholerestinases

Question 28

Importance of sleeping on physiology

Answer 28

- Lower energy available (more being used by daily activites) - Clears waste products away from the CNS - Neuronal plasticity - Immune function - Cognitive function

Question 29

General importance of sleep

Answer 29

``` -Experiments show similar sleep cycle in birds and mammals- die after being deprived of sleep for 2-3 weeks When deprived: -Cognitive function impaired -Irritable -Sluggish -impaired physical performance -Psychosis in extreme cases ```

Question 30

Sleep disorders

Answer 30

- Insomnia - Nightmares - Night terrors - Sleep walking - Narcolepsy

Question 31

Insomnia Definition Types Treatments

Answer 31

Defined as insufficient sleep to be able to maintain adequate daytime behaviours Affects 33% of adults Types: -Primary/Chronic- idiopathic -Secondary/ temporary- when related to pain Treatment: Barbituates: no longer used as chronic use showed they decrease amount of time spent in REM, stages 3 and 4, can increase amount of time it takes to fall asleep and can cause people to wake up numerous times during the night Benzodiapenes: can cause addiction, though have less effect on REM sleep Preferred method is to adjust sleep behavioural patterns

Question 32

Cause of narcolepsy

Answer 32

Insufficient Orexin being released

Question 33

What are night terrors

Answer 33

Very vivid visions in delta-sleep Occur in 3-8 year olds No recollection the next morning

Question 34

What are nightmares

Answer 34

very vivid in REM sleeping | Only way yo treat is by waking them up

Question 35

Somnabulism- in what stage does it occur?

Answer 35

Not in REM- in vert deep sleep