2. Introduction; methods in sleep research, sleep architecture

Question 1

Retrospective vs prospective methods to study sleep

Answer 1

retrospective = “how many times did that happen in the past month”

prospective = “here’s a sleep diary, keep it for a week”

Question 2

what does it mean behavioural measure of sleep

Answer 2

watching people sleep

Question 3

polysomnography

Answer 3

Records various physiological changes that occur during sleep: brain, muscles, eye movement. gold standard in sleep research. EEG + EOG + EMG + EKG. you put electrodes and they sleep like this.

Question 4

Actigraphy

Answer 4

measure gross levels of motor activity, when not moving maybe sleeping. it’s a watch-like device.

Question 5

issue with retrospective methods

Answer 5

people overestimate that stuff. I have a problem, i can NEVER sleep well. Inbuild bias.

Question 6

what’s best to counteract inbuild bias

Answer 6

prospective. ok it’s really 10 days out of 14.

Question 7

what are some issues with studying sleep through MRI?

Answer 7

• machine is noisy
• subjects can’t move
• invasive
• expensive
  + low temporal resolution

Question 8

depth electrodes

Answer 8

If you want to know what happens in the subcortical structures you need to implant electrodes past the neocortex into the deeper structures of the brain. In humans, we normally don’t do that stuff, the only way to get this type of information is people is through medical resistant epilepsy (epilectic crises that are not helped with medication), means you need surgery. Open up scalp, implant electrodes inside your brain.

Question 9

EOG

Answer 9

measures eye movements.
- used to categorize REM sleep
- use to see slow rolling eye movements during SWS

Question 10

EMG

Answer 10

measure of muscle tone. Electrodes of people’s chin, legs.

• used to detect muscle atonia characteristic of REM sleep
• used to diagnose some sleep disorders (ex. restless leg syndrome)

Question 11

EKG (ECG)

Answer 11

electrocardiogram: heart rate, heart activity. Electrodes around the chest and abdomen.

Suspicion of a heart disease, look at derivation during day and night

Question 12

EEG

Answer 12

electroencephalogram: recording of the brain’S electrical activity

We use it in sleep research for everything. When someone falls asleep, different stages of sleep, sleep disorders.

Question 13

frequency

Answer 13

number of cycles per second

Question 14

amplitude

Answer 14

how far from the baseline

Question 15

what does a higher amplitude mean

Answer 15

higher synchrony. all neurons same place, same time.

Question 16

limitation of EEG

Answer 16

summed up activity of gazilian neurons that are right under the scalp. not the ones deeper.

Question 17

beta, alpha, theta, delta

Answer 17

beta = wake
alpha = resting wake
theta = non rem stages 1&2 + REM
delta = slow wave sleep (non rem 3)

goes to smaller and smaller oscillation. Hz is thenumber of cycles per second

Question 18

what is sleep architecture

Answer 18

graphic representation of how your night went. different cycles.

Question 19

hypnogram is an example of

Answer 19

sleep architecture: progression of sleep stages