Sleep

Question 1

circadian rhythms

Answer 1

functions that have a 24 hr rhythm
may be behavioral, physiological, or biochemical- eg. thirst, body temp, hormone levels= all have biological origin

Question 2

diurnal

Answer 2

active during the light

Question 3

nocturnal

Answer 3

active during the dark

Question 4

biological clocks

Answer 4

leads to precise timing
endogenous- not quite 24 hr
entrain- (set) to light-dark cycles

Question 5

entrain clock

Answer 5

with continuous dim light, behavior becomes free-running
when the light cycle shifts, the behavior also shifts

Question 6

what allows for entrainment?

Answer 6

light (visual input)
meals
sleep
jobs/class
activity (exercise)
several of these inputs are also regulated by the biological clock

Question 7

suprachiasmatic nucleus (SCN)

Answer 7

biological clock in SCN in hypothalamus

Question 8

when SCN is damaged

Answer 8

if light/dark cycle maintained, no change in behavior
if only dim light, random behavior

Question 9

isolated SCN neurons

Answer 9

can create circadian rhythm via chemical release (encapsulated in plastic)

Question 10

SCN sequence

Answer 10

happens in a cycle (takes around 24 hrs- per/cry rises in light)
1. clock and cycle bind to form dimer
2. clock/cycle cause per and cry transcription
3. per and cry dimerize
4. per/cry inhibit clock/cycle activity
5. over time, per and cry degrade
6. allow clock and cycle to dimerize

Question 11

molecular clock based on cyclical levels of :

Answer 11

clock and cycle/Bmal1
per (period) and cry (cryptochrome)

Question 12

how does light information reach SCN?

Answer 12

retinal ganglion cells (RGC) project to SCN (retinohypothalamic pathway)

Question 13

retinal ganglion cells (RGC)

Answer 13

RGC do not get information from rod and cone cells
RGC contain melanopsin (sensitive to light, especially blue light)

Question 14

retinohypothalamic pathway

Answer 14

1. light causes glutamate release in SCN
2. glutamate increases Per and Cry transcription
3. synchronizes SCN neurons to each other and light/dark cycle

Question 15

classes of sleep

Answer 15

non-REM sleep (NREM)
rapid-eye-movement sleep (REM)

Question 16

monitoring sleep

Answer 16

electroencephalography (EEG)
electro-oculography (EOG)
electromyography (EMG)

Question 17

EEG

Answer 17

measures brain waves- brain potentials
synchronized routes of action potentials

Question 18

EOG

Answer 18

eye movements

Question 19

EMG

Answer 19

muscle tension

Question 20

non-REM sleep

Answer 20

has 3 stages and a reduction in postural tension

Question 21

REM sleep

Answer 21

has small-amplitude & fast EEG waves, no postural tension, and rapid eye movement

Question 22

stages of sleep

Answer 22

90-110 min
NREM (stages 1-3)
REM

Question 23

waking

Answer 23

while alert: mix of fast frequencies and low amplitude waves
called beta activity of desynchronized EEG

Question 24

stage 2

Answer 24

sleep spindles
if waken up during stage 1 or 2, the person may deny they were sleeping

Question 25

sleep spindles

Answer 25

bursts of activity waves

Question 26

stage 3

Answer 26

slow waves sleep (SWS) has large-amplitude, very slow waves called delta waves
synchronization of cortical activity

Question 27

REM

Answer 27

small-amplitude, high-frequency waves
no postural tension
rapid eye movements under eyelids
vivid dreams (vs. thinking)
REM sleep is sometimes called paradoxical sleep

Question 28

young adult sleep

Answer 28

young adults should sleep 8 hr/night
REM episodes lengthen
stage 3 disappears
approx 2 hr REM/night
cannot fully “repay” sleep debt

Question 29

Why do we sleep?

Answer 29

energy conservation
niche adaptation
body restoration
memory consolidation

Question 30

energy conservation

Answer 30

reduced muscle tension, heart rate, blood pressure

Question 31

niche adaptation

Answer 31

nocturnal vs. diurnal

Question 32

body restoration

Answer 32

toxin build-up in CSF flows out of brain faster

Question 33

memory consolidation

Answer 33

sleep helps you retain information
neuronal activity patterns of learning are repeated during stage 3
synaptic remodeling

Question 34

sleep centers

Answer 34

basal forebrain
reticular formation (wakefulness)
subcoeruleus

Question 35

basal forebrain

Answer 35

NREM
activity in basal forebrain- turns on non-REM sleep

Question 36

reticular formation

Answer 36

wakefulness
activated when you have to get up in the night

Question 37

subcoeruleus

Answer 37

REM sleep
basal forebrain stops being activated and subcoeruleus
paralysis of alpha motor neurons

Question 38

hypothalamus (4th sleep center)

Answer 38

hypocretin/orexin cells send information to 3 other sleep centers
control switch between awake, NREM, REM (narcolepsy and sleep paralysis)