sleep

Question 1

why are EEGs negative?

Answer 1

because sodium is rushing into the cell and depolarizing it

Question 2

synchronized activity description?
- when, shape

Answer 2

• neurons “in phase”
• summation causes large amp, low frequency EEG
• during sleep

Question 3

desynchronized activity description?
- when, shape

Answer 3

• neurons “out of phase”
• get a complicated rhythm
• low amp, high frequency
• when brain is active
• seen in REM sleep

Question 4

what are neural pacemakers?

Answer 4

• multiple VG channel types
• neurons can fire in rhythmic bursts of APs
• synchronized by thalamic input

Question 5

oscillator circits

Answer 5

• steady rate, drives inhibitory cell, then theres bursts of spikes, then quiet.
• delicate balance similar to adaptation in vision
• synchronized by each-other

Question 6

define a seizure?

Answer 6

abnormal synchronized brain activity

Question 7

what are the two main categories of seizures?
define them.

Answer 7

generalized
- affects entire brain, loose consciousness

partial/focal
- affects only a portion of the brain
- commonly associated with brain damage and tumors
- temporal lobe

Question 8

what are the types of generalized seizures?

Answer 8

grand mal / tonic-clonic

petit mal/focal

Question 9

describe grand mal

Answer 9

sudden onset
- recovery takes up to hours
- tonic phase: stiff limbs, may stop breathing
- clonic phase: rapid muscle contractions

Question 10

describe petit mal

Answer 10

Patient is completely dissociated from everything around them, only subtle motor signs

Question 11

what are the types of partial seizures?

Answer 11

simple

complex

Question 12

define simple partial

Answer 12

• retain awareness
• spasms

Question 13

complex partial

Answer 13

• loose consciousness (seem in a daze)
• graded start ans stop
• can last minutes
• temporal lobes are most commonly involved
• aura often precedes seizure

Question 14

what is eplilepsy?

Answer 14

• reoccurring seizures

Question 15

how to anticonvulsants work?

Answer 15

• shift excitatory/inhibitory balance
• can block Na+ channels, Gu receptors
• can inhibit metabolism or increase release of GABA

Question 16

what are other treatments for seizures?

Answer 16

• deep brain stimulation
• surgery
• keto diet (decrease neuron excitability)

Question 17

what are status seizures?

Answer 17

• rare seizures that last longer than 5 minutes
• can be fatal

Question 18

why do we sleep?

Answer 18

• conserve energy at night
• rest and recover
• memory consolidation
• disease prevention (obesity, alzheimers)
• self protection when most vulnerable

Question 19

what happens when rats did not sleep?

Answer 19

• weight loss
• temperature regulation disrupted
• weakened immune system
• death

Question 20

what would happened to randy when he did not to sleep?

Answer 20

• fatigue
• hallucinations
• speech
• memory
• he was fine after he slept

Question 21

how does sleep relate to memory?

Answer 21

hippocampus activity is increases

Question 22

how does sleep relate to memory?

Answer 22

hippocampus activity is increases

Question 23

what are the effects of sleep deprivation in humans?

Answer 23

• inc heart rate, blood pressure, heart attack and cortisol levels
• leptin decreases, ghrelin increases
• male and female hormone levels are reduced
• type 2 diabetes

Question 24

what is the glymphatic system?
what does it do?

Answer 24

• glial cells form channels along arteries and veins in the brain
• extracellular fluid carries away proteins and waste some of which can be toxic through cerebral spinal fluid

Question 25

what impact does loss of sleep have on the glymphatic system?

Answer 25

- removal of beta amyloid via the glymphatic system is impaired in alzheimers patients - sleep loss may contribute to this

Question 26

what is fatal familial insomnia disease? what causes it?

Answer 26

- rare disease triggered by mutation in gene that codes a prion protein - causes cell death in the thalamus (relay center), which leads to an inability to sleep symptoms - onset in 50s - insomnia - weight loss - dementia - uncoordinated movement - unable to walk or talk - death after 1-3 years

Question 27

what are the differences between REM and non-REM sleep?

Answer 27

REM = rapid eye movement, paradoxal sleep non-REM = slow wave

Question 28

what is the relationship between wave shape and sleep?

Answer 28

deeper sleep= bigger waves

Question 29

describe non-REM sleep?

Answer 29

- 75% of sleep - 4 stages based on EEG - low muscle tone and body movements - slow to no eye movement - occasional dreams - increased parasympathetic nervous system - dec heart rate, bp, breathing rate

Question 30

describe REM sleep?

Answer 30

- 25% of sleep - rapid eye movements - EEG looks awake - atonia=no muscle tone - increased sympathetic activity - complex dreaming

Question 31

what causes atonia in REM sleep? what are the results?

Answer 31

- inhibition of lower motor neurons - eyes, toes, fingers uninhibited

Question 32

what is atonia and REM sleep behavior disorder?

Answer 32

- loss of REM atonia

Question 33

what is the typical sleep cycle?

Answer 33

- progression from light to deep sleep to light sleep - there are about 5-7 cycles in a night

Question 34

how long is first REM episode to the last REM epidose?

Answer 34

- first = 10 minutes - last = 40-90 minutes

Question 35

what is the reticular activating system (RAS)?

Answer 35

- "little net" - consists of about 100 nuclei in the brain stem

Question 36

what occurs when the RAS is stimulated?

Answer 36

- RAS activates the brain - makes EEG jump from sleep to awake

Question 37

what happens when the rostral RAS is lesioned in an animal?

Answer 37

- animal is put into non-REM sleep or coma

Question 38

what does ATP have to do with sleep?

Answer 38

- the active brain uses more ATP which is broken down into adenosine and phosphate - less adenosine = more awake - more adenosine = more sleep pressure = neurons are more hyperpolarized as day goes on, more ATP is used and more adeonsine builds up in the system

Question 39

what is the suprachiasmatic nucleus (SCN)? what does it synchronize with?

Answer 39

- SCN is synchronized to light, but not dependent on it - SCN spikes when "light inhibits the Pineal gland for less release of melatonin"

Question 40

how does melatonin work?

Answer 40

- it is released when night begins to fall - makes us more aware that it is is dark outside - also associated with temperature

Question 41

what areas in the brain are most active during REM sleep and dreams?

Answer 41

- visual cortex

Question 42

what are the 3 principles of narcolepsy?

Answer 42

- REM sleep attacks - cataplexy - sudden atonia triggered by intense emotions - sleep paralysis - atonia that extends into time awake

Question 43

what is narcolepsy caused by?

Answer 43

degeneration of hypocretin neurons in the lateral hypothalamus