15. Sleep

Question 1

How do we measure brain activity?

Answer 1

By recording EEG by attaching electrodes to the scalp

Awake = noisy lines
Going to sleep = noisy lines
Deep sleep = constant oscillations
REM = more stable and straight

Question 2

How do we measure muscle activity?

Answer 2

By recording EMG by attaching electrodes to the chin

Question 3

What happens to our posture during sleep?

Answer 3

Our posture remains until REM -> when our muscles completely relax (despite brain activity looking more active)

Question 4

How do we record eye movements?

Answer 4

By recording EOG by attaching electrodes by the eyes

Question 5

What happens to our eye movement during sleep?

Answer 5

There is no eye movement until REM, during which our eyes move back and forth rapidly

Question 6

Beta activity

Answer 6

13-30 Hz, typical of aroused and focused state

Consists of high frequency, low amplitude oscillations

Question 7

Alpha activity

Answer 7

8-13 Hz, typical of awake person in relax state

Question 8

Theta activity

Answer 8

<4 Hz, occurs during deepest stages of slow-wave sleep

Question 9

REM

Answer 9

Rapid eye movement sleep

Associated with dreaming, rapid eye movements, desynchronized neural activity, and muscle paralysis

Question 10

What happens to cerebral blood flow and oxygen consumption during REM?

Answer 10

Both increase

Question 11

What happens when you lack sleep?

Answer 11

Mind begins to deteriorate, Increased in stress hormones, mood swings, impulsive behavior
Sleep debt created needs to be repaid

Question 12

What ist he correlation between larger animals and sleep and why (according to the restoration theory)?

Answer 12

Larger animals = less sleep because larger brains clean waste faster

Larger animals have lower basal metabolic rate per cell = each cell requires less energy overall

Question 13

Waste-removal theory

Answer 13

Cellular waste builds up in the brain during periods of wakefulness and decreases during sleep, gets washed away during the process of glymphatic system

Question 14

Ionic gradient rebalancing hypothesis

Answer 14

Rebalancing the ionic gradients to ensure optimal conditions for brain function

Question 15

Brain plasticity/learning & memory/synaptic homeostasis hypothesis

Answer 15

Neural networks reorganize as information is learned and forgotten

Think of a phone restarting to update

Question 16

Circadian rhythm

Answer 16

Changes in behavior and psychology that follow a 24-hour cycle, maintained in an internal clock

Question 17

Suprachiasmatic nucleus (SCN)

Answer 17

The master clock in our body located in the hypothalamus

Does not determine how much we sleep

Question 18

What is the 24-hour clock maintained by?

Answer 18

Two interlocking feedback loops

Question 19

Sleep molecule hypothesis

Answer 19

Some molecules promote sleep at high concentrations

Question 20

What molecule promotes sleep and how?

Answer 20

Adenosine by promoting vIPOA neurons

Question 21

What happens to signaling molecules during sleep?

Answer 21

Amount released decreases

Question 22

What are two arousal circuits?

Answer 22

Orexin and Histamine, neuropeptides released by neurons in the hypothalamus

Question 23

What do histamine receptor blockers (antihistamines) do?

Answer 23

Cause drowsiness

Question 24

What do norepinephrine and serotonin do during awake and sleep states?

Answer 24

Awake = firing, asleep = stop firing

Question 25

vIPOA

Answer 25

Ventrolateral preoptic area Area of hypothalamus that promotes sleep Electrical stimulation of vIPOA causes immediate sleep and drowsiness

Question 26

Orexin

Answer 26

Peptide produced by neurons in lateral hypothalamus that promote wakefulness

Question 26

What is the flip-flop circuit between sleep/awake and what does it entail?

Answer 26

vIPOA neurons > arousal neurons = sleep Arousal neurons > vIPOA neurons = awake Both cannot be activate at the same time

Question 27

Narcolepsy

Answer 27

Rare sleep disorder that includes excessive daytime sleepiness and irresistible urges to sleep Death of orexin neurons -> cannot control flip-flop circuit

Question 28

Sleep paralysis

Answer 28

Waking up consciously and not having control over the body

Question 29

Cataplexy

Answer 29

Experiencing complete muscle paralysis while awake, triggered by strong emotional reaction or sudden physical effort

Question 30

Insomnia

Answer 30

Difficulty falling asleep or after awakening during the night

Question 31

Fatal Familial Insomnia/Sporadic Fatal Insomnia

Answer 31

Rare diseases involving progressively worsening insomnia that can lead to death Associated with progressive neurodegeneration around the thalamus

Question 32

non-REM parasomnias

Answer 32

Sleep disorders that occur during non-REM sleep or during transitions out of sleep E.g., sleepwalking, sleep-talking

Question 33

Sleep terrors

Answer 33

Waking with an overwhelming feeling of terror Common between ages of 3-7 years old

Question 34

REM sleep behavior disorder

Answer 34

Person does not become paralyzed during REM sleep Associated with brain degeneration and often occurs prior to Parkinson's