Sleep/ARAS - Ruff

Question 0

What cells do EEGs measure? Why/How?

Answer 0

Pyramidal cells

• major cells in the cortex
• excitatory –> make electrical fields that EEGs can pick up
• are next to a lot of other pyramidal cells that do similar things (additive response)

Question 1

What is EEG?

Answer 1

Non-invasive measurement of brain activity using scalp electrodes

Question 2

What type of EEG wave is observed when someone is awake, has eyes open, or is actively thinking?

Answer 2

Beta wave

Question 3

What type of wave on an EEG has the highest frequency, but lowest amplitude?

Answer 3

beta wave

Question 4

What type of wave is observed on an EEG when someone is awake, has their eyes closed, and is relaxed?

Answer 4

alpha wave

Question 5

What type of EEG wave has a high frequency and large amplitude?

Answer 5

alpha wave

Question 6

What type of wave is observed on an EEG when someone is meditating or drowsy?

Answer 6

theta wave

Question 7

What type of EEG wave has low frequency and high amplitude?

Answer 7

theta wave

Question 8

What type of wave is observed on an EEG when someone is in slow-wave sleep?

Answer 8

Delta wave

Question 9

What type of EEG wave has the lowest frequency and highest amplitude?

Answer 9

delta wave

Question 10

What EEG changes occur during a seizure?

Answer 10

• General seizure: spike-wave pattern, wave patters everywhere
• Complex partial seizure: starts in a hemisphere and moves

Question 11

Why is it important to put EEG electrodes on the entire cortex in the case of a seizure?

Answer 11

So you can localize where the seizure starts/what parts of the brain are effected.

Question 12

What is seen in an EMG, EOG, and EEG while awake?

Answer 12

EMG - will have muscle tone
EOG - will have saccades
EEG - will have beta waves

Question 13

What is seen in an EMG, EOG, and EEG while in Non-REM sleep?

Answer 13

EMG - less muscle tone
EOG - no saccades, will have rolling motions of the eyes
EEG - no beta waves, just slow waves

Question 14

What is seen in an EMG, EOG, and EEG while in REM?

Answer 14

EMG - no muscle tone
EOG - the saccades will be present again
EEG - will have beta waves like when awake

Question 15

What are the changes in wave patterns during sleep Stages I-IV?

Answer 15

Stage I - decrease in frequency
Stage II - higher amplitude (sleep spindle) and even more increase in frequency (more coherent)
Stage III - lower frequency
Stage IV - lower frequency, higher amplitude, where restorative sleep takes place

Question 16

What system controls the sleep cycle?

Answer 16

Ascending reticular activating system

Question 17

What does the Ascending Reticular Activating System (ARAS) promote?

Answer 17

AWAKE state

Question 18

What monoaminergic nuclei/NT’s are involved in the sleep cycle (ARAS)?

Answer 18

Tuberomammillary nucleus - Histamine
Raphe nuclei - 5HT
Locus coeruleus - NE
VTA/Substantia nigra - DA

Question 19

What state does histamine promote?

Answer 19

Awake! That’s why antihistamines make you tired!

Question 20

What cholinergic nuclei/NT’s are involved in the ARAS?

Answer 20

Laterodorsal Tegmental Nucleus (LDT) - ACh
Pedunculopontine Nucleus (PPT) - ACh
Basal forebrain (BF) - ACh

Question 21

What neuropeptides does the Lateral Hypothalamus secrete and what are their actions?

Answer 21

Orexin - promotes AWAKE, stimulates monoaminergic/cholinergic nuclei to release NT to promote arousal

Melanin-concentrating horomone (MCH) - promotes REM SLEEP

Question 22

What condition is the result of the complete loss of orexin?

Answer 22

Narcolepsy

Question 23

What two conditions have partial loss of Orexin?

Answer 23

• Parkinson disease

- Traumatic Brain Injury

Question 24

What are Orexin antagonists used for?

Answer 24

sleep aids

Question 25

What two nuclei promote sleep by releasing inhibitory GABA and Galanin?

Answer 25

- Ventrolateral Preoptic Nucleus (VLPO) | - Median Preoptic Nucleus (MNPO)

Question 26

What inhibitory, "clear shield" structure that wraps around the thalamus contributes to sleep spindles and waves?

Answer 26

Thalamocortical Circuit | and corticothalamic projections

Question 27

In waking, the Laterodorsal Tegmental Nucleus (LDT) and the Pedunculopontine Nucleus (PPT) have what action on the thalamus and reticular nucleus of the thalamus?

Answer 27

- Excite Thalamus | - Inhibit reticular nucleus of the thalamus

Question 28

What action does the Reticular nucleus of the thalamus have when active?

Answer 28

Inhibition of the thalamus - wants you to SLEEP

Question 29

What is Non-REM sleep characterized by?

Answer 29

- "Waves" or oscillations in the EEG - Slow, rolling eye movements - Decreases in HR, BP, Temp, & Metabolic rate - Dreams are less frequent, vivid, and emotion than during REM sleep

Question 30

During Non-REM sleep, the LDT/PPT is inhibited by Preoptic nucleui, resulting in what?

Answer 30

- Reticular nucleus of the thalamus = Active - Reticular nucleus of the thalamus --> Inhibits thalamus in bursts - Thalamus bursts of hyperpolarization --> send bursts of AP's to the cortex --> excites pyramidal cells (oscillations) - Cortex/pyramidal cells send bursts back to reticular nucleus (increase bursts) and to the thalamus (stop bursts)

Question 31

During REM Sleep, the LDT/PPT are active, resulting in what?

Answer 31

- Inhibition of the reticular nucleus of the thalamus - Activation of the Thalamus --> Transmission Mode - Thalamus sends "sensory" info to cortex (about cortex, memories, experiences = crazy dreams)

Question 32

What two areas of the brain are active while dreaming?

Answer 32

- Anterior Cingulate Cortex = emotions | - Parahippocampal Gyrus = memories

Question 33

What area of the brain is inactive during dreaming and is the reason why you do crazy shit in your dreams?

Answer 33

Dorsolateral Prefrontal Cortex = responsible for impulse control

Question 34

Why is motor suppression during REM important?

Answer 34

Critical so you do not act out your dreams!

Question 35

Describe the Motor Suppression pathway during REM Sleep. | 3-4 steps

Answer 35

1. Lateral hypothalamus (MCH) - inhibits LC/Raphe (usually excites motorneurons) - activates Subceruleus nucleus 2. Subceruleus nucleus activates Ventromedial Medulla 3. Ventromedial medulla (glycinergic) inhibits motor neurons in the spinal cord = REM atonia

Question 36

What action does the LC/Raphe have during Non-REM/Wake states?

Answer 36

1. Activates motor neurons of the spinal cord | 2. Inhibits LDT/PPT

Question 37

What are possible functions of sleep?

Answer 37

- Reducing energy expenditure - Replenish brain glycogen - Cognition = brain plasticity; consolidation, association, and pruning of memories; consolidation of learning - Metabolic clearance = Glymphatic system

Question 38

What are the short term consequences/effects of sleep deprivation?

Answer 38

-Cognitive impairment: reaction time, judgement

Question 39

What are the long term consequences/effects of sleep deprivation?

Answer 39

- Cognitive decline - Problems with homeostasis (metabolism, temperature) - Infections - Hallucinations, seizures - Death

Question 40

Is REM sleep necessary?

Answer 40

NO

Question 41

What happens in sleep apnea?

Answer 41

Only get to STAGE II: - muscle tone decreases in Non-REM sleep - palate muscle becomes relaxed and airway gets blocked - body wake you up to start breathing - patient are unable to reach Stage III and IV to get restorative sleep

Question 42

What happens in REM behavior disorder?

Answer 42

- Loss of REM atonia = muscle tone during REM - Ranges from talking/small movements to acting out dream - 80% later develop alpha-synucleinopathies (parkinson's/lewy bodies) (may be first symptom of parkinson's)