Chapter 5: Variations in consciousness(1)

Question 1

Define consciousness.

Answer 1

Consciousness is the awareness of internal and external stimuli.

Question 2

Define mind-wandering.

Answer 2

Mind wandering refers to people’s experience of task-unrelated thoughts, thoughts that are not related to what they are intentionally trying to do at a given moment.

(CS)

Question 3

What is the most commonly used indicator of variations in consciousness?

Answer 3

The electroencephalograph (EEG) is a
device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp.

Question 4

What are the processes and structures of the brain that are implicated in mind wandering?

Answer 4

Default mode network and the fronto-parietal network.

(CS)

Question 5

Human brain-wave activity is usually divided into four principal bands, Name them and their state of consciousness.

Answer 5

Beta (β) : Normal waking thought, alert problem-solving
Alpha (α): Deep relaxation, blank mind, meditation
Theta (θ): Light sleep
Delta (Δ) : Deep sleep

Question 6

What are biological rhythms and what do they tell you?

Answer 6

Biological rhythms are periodic fluctuations in physiological functioning.

The existence of these rhythms means that organisms have internal “biological clocks” that somehow monitor the passage of time.

(CS)

Question 7

Define circadian rhythms.

Answer 7

Circadian rhythms are the 24-hour biological cycles found in humans and many other species.

Question 8

What are the functions of circadian rhythms?

Answer 8

1. regulation of sleep
2. blood pressure
3. urine production
4. hormonal secretion

Question 9

How does the day-night cycle reset biological clocks?

Answer 9

When exposed to light, some receptors in
the retina sends direct inputs to a small structure in the hypothalamus called the suprachiasmatic nucleus.

The SCN sends signals to the nearby pineal
gland, whose secretion of the hormone melatonin
plays a key role in adjusting biological clocks.

Question 10

Define social jet lag.

Answer 10

This mismatch between sleep times on
workdays versus off days have been labeled social jet lag.

Question 11

What is an electromyograph and electrooculograh and what are they used for?

Answer 11

An electromyograph (EMG), which
records muscular activity and tension, and an electrooculograph (EOG), which records eye movements

Question 12

What are the events in the first stage of sleep?

Answer 12

1. A brief stage of light sleep
2. Breathing and heart rate slow as muscle tension and body temperature decline.
3. Theta waves are prominent
4. Hypnic jerks occur.

Question 13

What are the events of stage 2?

Answer 13

1. Brief bursts of higher-frequency brain waves called sleep spindles.
2. Brain waves become higher in amplitude and slower in frequency, as the body moves into a deeper form of sleep, called slow­wave sleep.

Question 14

What happens after a person reaches slow wave sleep?

Answer 14

Once individuals reach slowwave sleep they stay there for roughly 30 minutes.

Then the cycle reverses itself and the sleeper gradually moves back upward through the lighter stages.

Question 15

What are the events of stage 3&4 sleep?

Answer 15

During slow-wave sleep (SWS), sleep stage 3, high-amplitude, low-frequency delta waves become prominent in EEG recordings.

Question 16

What is REM sleep?

Answer 16

When sleepers reach what should be stage 1 once again, they usually go into the fifth stage of sleep, which is most widely known as REM sleep.

REM is an abbreviation for the rapid eye movements prominent during this stage of sleep.

Question 17

What are the events of the 5th stage/REM stage?

Answer 17

1. A “deep” stage of sleep that people are relatively hard to awaken from it.
2. Irregular breathing and pulse rate.
3. Muscle tone is extremely relaxed—and the sleeper is virtually paralyzed.
4. Dominated by high­frequency
   beta waves.
5. Dream reports are more likely during the REM stage.

Question 18

How are NREM stages marked?

Answer 18

NREM sleep consists of sleep stages 1 through 3, which are marked by an absence of rapid eye movements, relatively little dreaming, and varied EEG activity

Question 19

How many times are the stages of sleep repeated?

Answer 19

4.

Question 20

Explain sleep trends in babies and infants.

Answer 20

Newborns will sleep a total of 16 hours of
sleep.

Infants spend much more of their sleep time in the REM stage than adults do.

Question 21

What is one brain structure important for sleep and wakefulness?

Answer 21

One brain structure that is important to
sleep and wakefulness is the reticular formation in the core of the brainstem.

Question 22

What is the ARAS?

Answer 22

The ascending reticular activating system
(ARAS) consists of the afferent fibers running through the reticular formation that influence physiological arousal.

Question 23

What happens when the fibres of ARAS is cut?

Answer 23

When these ascending fibers are cut in
the brainstem of a cat, the result is continuous sleep.

Question 24

What are the brain structures critical for
the generation of REM sleep?

Answer 24

Activity in the pons and adjacent areas in the midbrain.

Question 25

What are the 3 hypothesis of sleep?

Answer 25

1. Sleep evolved to conserve organisms’ energy.
2. The inactivity of sleep is adaptive because it reduces exposure to predators
   and the consumption of precious resources.
3. Sleep is adaptive because it helps
   animals restore bodily resources depleted by waking activities.