9.3 Why Sleep? Why Rem? Why Dream?

Question 0

____ serves many functions. During sleep, we rest our muscles, decrease metabolism, rebuild proteins in the brain, reorganise synapses, and strengthen memories.

Answer 0

Sleep

Question 1

You feel tired at the end of the day because ____ processes in your brain force you to become less aroused and less alert.

Answer 1

inhibitory

Question 2

People who don’t get enough sleep have trouble concentrating and become more vulnerable to illness, especially ____ ____.

Answer 2

mental illness

Question 3

Even one night of sleeplessness activates the ____ ____. That is, you react to sleep deprivation as if you were ill. With more prolonged sleep deprivation, people report dizziness, tremors, and hallucinations.

Answer 3

immune system

Question 4

During sleep, a mammals body temperature decreases by 1° or 2°C, enough to save a significant amount of ____.

Answer 4

energy

Question 5

Also during sleep, ____ activity decreases, saving more energy.

Answer 5

muscle

Question 6

Animals ____ their sleep duration during food shortages, when energy conservation is especially important.

Answer 6

increase

Question 7

If one of the main functions of sleep is to shutdown activities at times of relative inefficiency, we might expect to find _________ in species that are equally effective at all times of the day. This appears to be true.

Answer 7

little or no sleep

Question 8

Another apparent function of sleep is improved ____.

Answer 8

memory

Question 9

If people learn something and then go to ____, or even take a nap, their memory often improves beyond what it was before the sleep.

Answer 9

sleep

Question 10

Sleep also helps people ____ their memories: in one study, people who just practised a complex task were more likely to perceive a hidden rule after a period of sleep than after a similar period of wakefulness.

Answer 10

reanalyse

Question 11

Another study found that a nap that included REM sleep enhanced performance on certain kinds of ____ ____ ____.

Answer 11

creative problem solving

Question 12

Researchers recorded activity in the ____ during learning, and then recorded the same locations during sleep. Results: patterns that occurred during sleep resembled those that occurred during learning, except that they were more rapid during sleep.

Answer 12

hippocampus

Question 13

The amount of hippocampal activity during sleep correlated highly with subsequent improvement in ____.

Answer 13

performance

Question 14

These results suggest that the brain ____ its daily experiences during sleep.

Answer 14

replays

Question 15

The hippocampus replays recently learned patterns during quiet ____ periods, not just during sleep.

Answer 15

waking

Question 16

Another aspect of sleeps contribution to memory relates to sleep spindles. They indicate an exchange of information between the ____ and the ____ ____. In both rats and humans, sleep spindles increase in number after new learning.

Answer 16

thalamus : cerebral cortex.

Question 17

Dream research faces a special problem: what we know that dreams comes from people’s ____, and researchers have no way to check the accuracy of those reports.

Answer 17

self-reports

Question 18

According to the ____-____ ____, a dream represents the brains efforts to make sense of sparse and distorted information.

Answer 18

activation-synthesis hypothesis

Question 19

Dreams begin with periodic bursts of spontaneous activity in the ____ – the PGO waves previously described – that activates some parts of the cortex but not others.

Answer 19

pons

Question 20

The ____ combines this haphazard input with whatever other activity was already occurring and does its best to synthesise a story that makes sense of the information.

Answer 20

cortex

Question 21

____ ____, such as sounds in the room, occasionally get incorporated into a dream, although usually they do not.

Answer 21

Sensory stimuli

Question 22

An alternative view of dreams has been labelled the ____ ____ because it was derived from the clinical studies of patients with various kinds of brain damage.

Answer 22

clinicoanatomical hypothesis

Question 23

Clinicoanatomical hypothesis emphasises that dreams begin with arousing stimuli that are ____ within the brain combined with recent memories and any information the brain is receiving from the senses.

Answer 23

generated

Question 24

However, the clinico-anatomical hypothesis puts less emphasis on the pons, PGO waves, or REM sleep. It regards dreams as thinking that takes place under unusual conditions, similar to ______ during everyday life.

Answer 24

mind-wondering

Question 25

Patients with damage to the ____ ____ have problems binding body sensations with vision. They also report no dreams.

Answer 25

parietal cortex

Question 26

Fairly high activity is also found in the areas of the ____ ____ outside V1. Those areas are presumably important for the visual imagery that accompanies most dreams.

Answer 26

visual cortex

Question 27

Finally, activity is high in the ____, ____, and other areas important for emotions and motivations.

Answer 27

hypothalamus, amygdala