Consciousness

1. Continuum of Consciousness • Consciousness refers to different levels of awareness of one’s thoughts and feelings. • It may include creating images in one’s mind; following one’s thought processes, or having unique emotional experiences. • The continuum of consciousness refers to a wide range of experiences, from being acutely aware and alert to being totally unaware and unresponsive. • Some of the experiences that make up the continuum of consciousness.

2. Controlled processes: • Controlled processes are activities that require full awareness, alertness, and concentration to reach some goal. • A controlled process such as talking on a cell phone while driving involves focusing most of your attention on talking and little on driving.

3. Automatic processes: • Automatic processes are activities that require little awareness, take minimal attention, and do not interfere with other ongoing activities. • Examples of automatic processes include eating while reading or watching television

4. Daydreaming: • Daydreaming is an activity that requires a low level of awareness, often occurs during automatic processes, and involves fantasizing or dreaming while awake. • We may begin daydreaming in a relatively conscious state and then drift into a state between sleep and wakefulness.

5. Altered states of consciousness: • Altered states of consciousness result from using any number of procedures—such as meditation, psychoactive drugs, hypnosis, or sleep deprivation—to produce an awareness that differs from normal consciousness. • We enter an altered state of consciousness every night when we go to sleep.

6. Sleep and Dreams: • Sleep consists of five different stages that involve different levels of awareness, consciousness, and responsiveness, as well as different levels of physiological arousal. • The deepest state of sleep borders on unconsciousness. • Because of our decreased awareness, 8 hours of sleep may seem like one continuous state. • However, it is actually composed of different states of body arousal and consciousness • One interesting sleep state involves dreaming. • Dreaming is a unique state of consciousness in which we are asleep but experience a variety of astonishing visual, auditory, and tactile images, often connected in strange ways and often in color. • People blind from birth have only auditory or tactile dreams.

7. Rhythms of Sleeping & Waking • Biological Clocks: • Biological clocks are internal timing devices that are genetically set to regulate various physiological responses for different periods of time. • Biological clocks can be set for hours (secretion of urine), for a single day (rise and fall in internal body temperature), or for many days (women’s 28-day menstrual cycle). • A circadian rhythm refers to a biological clock that is genetically programmed to regulate physiological responses within a time period of 24 hours (about one day).

8. Length of day: • However, in a better controlled study, researchers reported that for both young (mean age 24) and older (mean age 67) adults, the sleep-wake circadian clock is genetically set for a day lasting an average of 24 hours and 18 minutes (Czeisler et al., 1999). • Resetting the circadian clock: • Because your circadian clock is genetically set for about 24 hours, 18 minutes, it must be reset each day to match our agreed upon 24-hour-long day. • The resetting stimulus is morning sunlight, which stimulates newly discovered light-detecting cells in the eye’s retina (see p. 96) (Purves et al., 2008). • These retinal cells, which are involved in sensing the amount of light and are not involved in seeing, send electrical signals to the brain’s circadian clock and reset it by about 18 minutes each day.

9. Circadian Problems and Treatments: • Shift Workers: • Staying awake when your sleep-wake clock calls for sleep results in decreased performance in cognitive and motor skills (Drummond, 2000). • For example, employees who work the graveyard shift (about 1–8 A.M.) experience the highest number of accidents, reaching their lowest point, or “dead zone,” at about 5 A.M., when it is very difficult to stay alert. • Jet lag: • It is the experience of fatigue, lack of concentration, and reduced cognitive skills that occurs when travelers’ biological circadian clocks are out of step or synchrony with the external clock times at their new locations. • Resetting Clock: • Light therapy is the use of bright artificial light to reset circadian clocks and to combat the insomnia and drowsiness that plague shift workers and jet-lag sufferers. • It also helps people with sleeping disorders in which the body fails to stay in time with the external environment.

10. Melatonin: • It is a hormone that is secreted by the pineal gland, an oval-shaped group of cells that is located in the center of the human brain. • Melatonin secretion increases with darkness and decreases with light. • The suprachiasmatic nucleus regulates the secretion of melatonin, which plays a role in the regulation of circadian rhythms and in promoting sleep.

11. Stages of Sleep: • The stages of sleep refer to distinctive changes in the electrical activity of the brain and accompanying physiological responses of the body that occur as you pass through different phases of sleep. • The alpha stage is marked by feelings of being relaxed and drowsy, usually with the eyes closed. • Alpha waves have low amplitude and high frequency (8–12 cycles per second).

12. Non-REM Sleep: • Non-REM sleep is where you spend approximately 80% of your sleep time. • Non-REM is divided into sleep stages 1, 2, 3, and 4; each stage is identified by a particular pattern of brain waves and physiological responses. • (REM stands for rapid eye movement.)

13. Stage 1: • This is the lightest stage of sleep. • Stage 1 sleep is a transition from wakefulness to sleep and lasts 1–7 minutes. • In it, you gradually lose responsiveness to stimuli and experience drifting thoughts and images. • Stage 1 is marked by the presence of theta waves, which are lower in amplitude and lower in frequency (4–7 cycles per second) than alpha waves.

16. Stage 2: • This is the first stage of what researchers call real sleep. • Stage 2 sleep marks the beginning of what we know a sleep, since subjects who are awakened in stage 2 report having been asleep. • EEG tracings show high-frequency bursts of brain activity called sleep spindles.

17. Stages 3 and 4: • About 30–45 minutes after drifting off into sleep, you pass through stage 3 and then enter into stage 4 sleep. • Stage 4 sleep, which is also called slow-wave or delta sleep, is characterized by waves of very high amplitude and very low frequency (less than 4 cycles per second) called delta waves. • Stage 4 is often considered the deepest stage of sleep because it is the most difficult from which to be awakened. • During stage 4, heart rate, respiration, temperature, and blood flow to the brain are reduced, and there is a marked secretion of GH (growth hormone), which controls levels of metabolism, physical growth, and brain development.

18. REM sleep: • REM sleep makes up the remaining 20% of your sleep time. • It is pronounced “rem” and stands for rapid eye movement sleep because your eyes move rapidly back and forth behind closed lids. • REM brain waves have high frequency and low amplitude and look very similar to beta waves, which occur when you are wide awake and alert. • During REM sleep, your body is physiologically very aroused, but all your voluntary muscles are paralyzed. • REM sleep is highly associated with dreaming. • You pass into REM sleep about five or six times throughout the night with about 30 to 90 minutes between periods. • You remain in each period of REM sleep for 15 to 45 minutes and then pass back into non-REM sleep.

19. REM—Dreaming and Remembering: • Dreaming: • One of the biggest breakthroughs in dream research was the finding that about 80–90% of the times when subjects are awakened from a REM period, they report having vivid, complex, and relatively long dreams (Dement, 1999). • In contrast, only about 10% of subjects awakened from non-REM sleep report similar kinds of dreams. • One of the first questions asked was what happens when people are deprived of REM sleep and dreaming. • Many subjects have been deprived of REM sleep and dreaming without showing any major behavioral or physiological effects (Bonnet, 2005). • However, suppressing REM sleep does produce a curious phenomenon called REM rebound. • REM rebound refers to individuals spending an increased percentage of time in REM sleep if they were deprived of REM sleep on the previous nights.

20. Remembering: • The occurrence of REM rebound suggests a need for REM sleep, and one such need involves memory. • In one study, subjects learned to press a button when they spotted a moving target on a screen. • Subjects tested on the same day as training showed a modest improvement. However, when subjects were tested the next day, those subjects allowed to get the most REM sleep (slept 8 hours) showed the greatest improvement compared to subjects who got the least REM (slept 6 hours). • Researchers concluded that REM sleep helps us store or encode information in memory and advise students to get a good night’s sleep so that what they studied the previous day has a chance to be stored in the brain’s memory (Stickgold, 2000, 2005).