Sleep

Question 1

What are effects of not sleeping?

Answer 1

bad mood, memory, and attention
Chronic sleep deprivation is linked to neurodegeneration

Question 2

What are the stages of sleep?

Answer 2

NREM (non rapid eye movement) and REM alternates, deep sleep of NREM, REM

Question 3

What goes along with NREM?

Answer 3

slow wave sleep
hard to wake up

Question 4

What goes along with REM?

Answer 4

paradoxical sleep
awake-like brain activity, vivid dreams

Question 5

Why do we get sleepy?

Answer 5

Homeostatic “sleep pressure” builds up as more time is spent awake and pressure relieved by sleep

Question 6

What do somnogens do?

Answer 6

substance that causes or induces sleepiness
may mediate sleep pressure

Question 7

What does adensosine do?

Answer 7

important somnogen
binding receptors expressed on surface membrane of neurons (A1 and A2A)
Astrocytes (glial cells) are main source of adenosine

Question 8

What does NBTI do?

Answer 8

blocks removal of adenosine from extracellular space

Question 9

What does the A1 receptor do?

Answer 9

inhibit wake-promoting neurons

Question 10

What does A2A receptors do?

Answer 10

excite sleep promoting neurons

Question 11

What does caffeine do?

Answer 11

blocks both A1 and A2A receptors

Question 12

What are circadian rhythms?

Answer 12

internal biological clock that coordinates our physiology and behavior (e.g. body temp, hormone levels, cognitive performance, sleep) with the day-night cycle
24h long

Question 13

What is the suprachiasmatic nucleus (SCN)?

Answer 13

pacemaker in the hypothalamus that is the master regulator of circadian rhythms in mammals

SCN has an intrinsic circadian rhythm

Light “entrains” SCN pacemaker activity to match the environmental light-

Question 14

What is von Economo’s sleeping sickness?

Answer 14

patients slept excessively

patients had brain lesions where brainstem meets forebrain and in anterior hypothalamus.

observed smaller fraction of patients that had
insomnia and only slept a few hours each day (had lesions in the anterior hypothalamus)

Question 15

What happened to adenosine levels in the cat throughout the day?

Answer 15

levels rise as it is awake longer, drops when asleep
when levels are artificially high it slept longer than normal

Question 16

What does the suprachiasmatic nucleus do?

Answer 16

has high activity through the day and low at night and helps regulate when the body wants to sleep
located in the hypothalamus

Question 17

What does the hypothalamus do in the brain?

Answer 17

controls things that are uncontrollable in the body: temperature, breathing, heart rate, hunger, sleep regulation

Question 18

What is the wakefulness neuron called?

Answer 18

orexin (hypocretin)

Question 19

what is narcolepsy?

Answer 19

chronic sleep issues (sleepy during the day, fragmented at night)

REM aspects can happen at any time of the day
cataplexy: sudden muscle paralysis by strong emotions
sleep paralysis
vivid hallucinations when falling asleep

Question 20

What are the 3 functions of sleep?

Answer 20

memory consolidation
synapse homeostasis
metabolic waste clearance

Question 21

what does memory consolidation do?

Answer 21

repeated replay of wake cell firing patterns helps transfer short term memory to long term memory
(hippocampus to cortex)
repeated stuff– neurons that fire together wire together

Question 22

what does synaptic homeostasis do?

Answer 22

synapses become strengthened during learning and activity during sleep leads to reduction in synapse
(so that the synapse strength is cut down– thats why it takes so long to learn things (takes multiple days of study))

Question 23

what does waste clearance do in the brain?

Answer 23

clears toxins from the brain tissues and during sleep clearance is enhanced
spaces between cells expand, brain and blood vessel activity do slow wave activity (deep sleep)