Sleep Flashcards
What are effects of not sleeping?
bad mood, memory, and attention
Chronic sleep deprivation is linked to neurodegeneration
What are the stages of sleep?
NREM (non rapid eye movement) and REM alternates, deep sleep of NREM, REM
What goes along with NREM?
slow wave sleep
hard to wake up
What goes along with REM?
paradoxical sleep
awake-like brain activity, vivid dreams
Why do we get sleepy?
Homeostatic “sleep pressure” builds up as more time is spent awake and pressure relieved by sleep
What do somnogens do?
substance that causes or induces sleepiness
may mediate sleep pressure
What does adensosine do?
important somnogen
binding receptors expressed on surface membrane of neurons (A1 and A2A)
Astrocytes (glial cells) are main source of adenosine
What does NBTI do?
blocks removal of adenosine from extracellular space
What does the A1 receptor do?
inhibit wake-promoting neurons
What does A2A receptors do?
excite sleep promoting neurons
What does caffeine do?
blocks both A1 and A2A receptors
What are circadian rhythms?
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
What is the suprachiasmatic nucleus (SCN)?
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-
What is von Economo’s sleeping sickness?
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)
What happened to adenosine levels in the cat throughout the day?
levels rise as it is awake longer, drops when asleep
when levels are artificially high it slept longer than normal
What does the suprachiasmatic nucleus do?
has high activity through the day and low at night and helps regulate when the body wants to sleep
located in the hypothalamus
What does the hypothalamus do in the brain?
controls things that are uncontrollable in the body: temperature, breathing, heart rate, hunger, sleep regulation
What is the wakefulness neuron called?
orexin (hypocretin)
what is narcolepsy?
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
What are the 3 functions of sleep?
memory consolidation
synapse homeostasis
metabolic waste clearance
what does memory consolidation do?
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
what does synaptic homeostasis do?
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))
what does waste clearance do in the brain?
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)
