Module 5: Dual Processing, Sleep, and Dreams

The Brain and Consciousness Psychology began in the 1800's as “the description

and explanation of states of consciousness.” During the first half of the 20th century Psychology

focused only on directly observable behavior. After 1960, however, the idea of distinct states of

mind and mental processes began to remerge. Advances in neuroscience made it possible to relate brain activity to activities such as sleeping, dreaming, and other mental states.

Currently psychologists affirm the importance of cognition, or internal mental processes.

The Brain and Consciousness Consciousness- Our awareness of ourselves and

our environments. Some psychologists speculate that consciousness

– the awareness of awareness – offers an evolutionary advantage (for example, by helping us act on our long term interests by considering consequences and reading others' intentions).

How do collections or networks of neurons communicating with each other give rise to such subjective experiences as contentment, pain, and anxiety?

States of Consciousness

Dual Processing

One of the central ideas of cognitive neuroscience is that much of our brain processes information outside of our conscious awareness.

Perception, memory, thinking, language and attitudes all operate at two levels – a conscious deliberate “high road” and an unconscious automatic “low road”.

The Two Track Mind

Dual Processing- The principle that information is often simultaneously processed on separate conscious and unconscious tracks.

For example, vision is actually the result of a dual processing system. One system, the visual perception track, enables us recognize objects and plan future actions. The second system, a visual action track, guides our moment to moment actions.

Hollow Face Illusion

On rare occasions, the two conflict. Shown the hollow face illusion, people will mistakenly perceive the inside of a mask as a protruding face...

Yet they will unhesitatingly and accurately reach into the inverted mask to flick off a buglike target stuck to the face. What their mind doesn't know, their “hand does”.

Hollow Face Illusion

The Two Track Mind

Unconscious Parallel Processing- The brain's ability to do multiple things simultaneously. This frees the conscious mind to deal with new challenges. For example, traveling by car on a familiar route, your hands and feet do the driving while your mind rehearses the upcoming day.

Serial Conscious Processing- Doing things one step at a time. Though slower than parallel processing, this allows for attention to be directed towards solving new problems. For example, you can write the number three or move your foot in a circle although probably not do both at the same time.

Selective Attention

The focusing of conscious awareness on a particular stimulus. Conscious awareness is usually focused on a very limited aspect of everything we experience.

By one estimate, the five senses take in 11,000,000 bits of information per second, of which consciousness processes about 40.

Selective Attention

The cocktail party effect is the ability to attend to only one voice among many. When paying attention to one voice or conversation, other surrounding voices and conversations may only be recalled in terms of a speakers gender and / or loudness.

Selective Attention and Accidents

Talking on the phone while driving requires one's selective attention to shift back and forth from the road to the phone.

80% of motor vehicle crashes involve driver distraction.

Cell phone use while driving increases the likelihood of having an accident 4 times while having a passenger increases it 1.6 times.

Even hands free cell phone talking is more distracting than a conversation with passengers who can see the driving demands and pause the conversation.

Selective Inattention

At the level of conscious awareness we are “blind” to all but a tiny amount of the visual stimuli we perceive.

Inattentional Blindness - Failing to see visual objects when our attention is directed elsewhere.

- Ex. Gorilla suit Change Blindness - Failing to notice changes in

the environment.

- Ex. Giving directions to a construction worker.

Sleep and Dreams

Even when you are deep asleep, your perceptual window is not completely shut.

Low frequency sounds leave sleepers undisturbed but high frequency sounds, such as a babies cry, interrupts it.

Many of sleep's mysteries are now being solved by EEG research that measures Cerebral Cortex electrical activity.

Sleep and Dreams:True or False

When most people dream of performing some activity, their limbs often move in concert with the dream.

Older adults sleep more than young adults. Sleepwalkers are acting out their dreams. Sleep experts recommend treating insomnia

with an occasional sleeping pill. Some people dream every night; others seldom

dream.

Circadian Rhythm Circadian Rhythm- The biological clock; regular body rhythms,

for example of temperature and wakefulness) that occur on a 24 hour cycle.

Body temperature rises as morning approaches, peaks during the day, dips for a time in the early afternoon, and begins to drop before we go to sleep.

Bright light activates light sensitive retinal proteins which send signals to the brain's suprachiasmatic nucleus- a pair of rice sized cell clusters in the hypothalamus. The suprachiasmatic nucleus operates by causing the brain's pineal gland to decrease its production of sleep inducing hormone melatonin in the morning or increase it in the evening.

Bright light at night helps delay sleep and resets our biological clock when we stay up late and sleep on weekends.

Bright light helps to reset the biological clock.

Suprachiasmatic Nucleus

Sleep Stages Alpha Waves- Relatively slow brain waves of a relaxed, awake state.

Stage 1 Sleep- During this stage you may experience fantastic images, resembling hallucinations. May have sensations of falling or floating weightlessly. Such hypnagogic sensations may later be incorporated into memories. “Out of body experience,” stage of sleep.

Stage 2 Sleep- Characterized by sleep spindles, bursts of rapid, rhythmic brain activity. Can still be awakened without too much difficulty.

Stage 3 Sleep- Transition to long, slow delta wave sleep.

Stage 4 Sleep- Delta wave sleep. These two slow wave stages last for about 30 minutes, during which it is difficult to be awakened. It is at the end of deep sleep that children may wet the bed or sleep walking occurs. 20% of 3 – 12 year olds have at least one episode of sleep walking. 5% have repeated episodes.

REM Sleep

REM Sleep

For about 10 minutes before waking, brain waves become rapid and saw-toothed, more like those of the nearly awake Stage 1 sleep. But unlike Stage 1 sleep, during REM sleep your heartrate rises, your breathing becomes rapid and irregular, and every half-minute or so your eyes dart around in momentary bursts of activity behind closed lids.

REM sleep was first discovered in 1952.

Although the brains motor cortex is active during REM sleep, your brain blocks its messages, leaving muscles relaxed – so relaxed that, except for an occasional finger, toe, or facial twitch, you are essentially paralyzed.

Moreover you cannot be easily awakened. REM sleep is sometimes called paradoxical sleep since with the body internally aroused and externally calm.

REM Sleep

For about 10 minutes before waking, brain waves become rapid and saw-toothed, more like those of the nearly awake Stage 1 sleep. But unlike Stage 1 sleep, during REM sleep your heartrate rises, your breathing becomes rapid and irregular, and every half-minute or so your eyes dart around in momentary bursts of activity behind closed lids.

REM sleep was first discovered in 1952.

Although the brains motor cortex is active during REM sleep, your brain blocks its messages, leaving muscles relaxed- so relaxed that, except for an occasional finger, toe, or facial twitch, you are essentially paralyzed. Moreover you cannot be easily awakened. REM sleep is sometimes called paradoxical sleep since with the body internally aroused and externally calm.

REM Sleep

REM sleep indicates the beginning of dreams.

The sleep cycle repeats itself about every 90 minutes. As the night goes on deep Stage 4 sleep gets progressively shorter and then disappears.

People experience about 600 hours a year dreaming and have more than 100,000 dreams over a typical lifetime.

Why Do We Sleep?

The idea that everyone needs 8 hours of sleep is untrue.

Newborns spend nearly 2/3 of their day asleep, and adults no more than 1/3.

Sleep patterns are genetically influenced. In twin study's of fraternal and identical twins, only the identical twins sleep patterns were strikingly similar.

Sleep patterns are culturally influenced. Thanks to modern light bulbs, shift work, and social diversions, those who would have gone to bed at 9:00 PM are now up until 11:00 PM.

The Effects of Sleep Loss

Teens who typically need 8 to 9 hours of sleep now average less than seven, nearly two hours less each night than their counterparts of 80 years ago.

28% of high school students acknowledged falling asleep in class at least once a week.

Sleep deprivation entails difficulty studying, diminished productivity, tendency to make mistakes, irritability, and fatigue.

Sleep Deprivation increases ghrelin, a hunger arousing hormone, and decreases leptin, a hunger suppressing hormone.

Deprivation also increases cortisol, a stress hormone that stimulates the body to make fat. Children and adults who sleep less than normal are fatter than those who sleep more.

Why Do We Sleep? Sleep protects- From an evolutionary perspective, sleeping at

night kept humans from dangerous situations and allowed them to survive.

Sleep helps us recuperate- Sleeping helps restore and repair brain tissue. Sleep gives neurons time to repair themselves while allowing unused connections to weaken.

Sleep is for making memories- People trained to perform tasks recall them better after a nights sleep. In both humans and rats, neural activity during slow wave sleep re-enacts and promotes recall of prior novel experiences.

Sleep also feeds critical thinking- Dreams inspire noteworthy literary, artistic, and scientific achievements.

Sleep may play a role in the growth process- During sleep the pituitary gland releases growth hormone. As we age, we release less hormone and spend less time sleeping.

Sleep Disorders

Insomnia- A recurring problem in falling or staying asleep. 1 in 10 adults, and 1 in 4 older adults complain of insomnia.

Narcolepsy- A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times. These episodes usually last about 5 minutes.

Sleep Apnea- A sleep disorder characterized by temporary cessation of breathing during sleep and repeated momentary awakenings.

Night Terrors- A sleep disorder characterized by high arousal and appearance of being terrified; unlike nightmares, night terrors occur during stage four sleep, within two or three hours of falling asleep, and are seldom remembered.

What We Dream?

What do we dream?

Daydreams involve familiar details of our lives whereas REM dreams are vivid, emotional, and bizzare.

We spend about six years of our lives in dreams.

People commonly dream of repeatedly failing in an attempt to do something; of being attacked, pursued, or rejected; or experiencing misfortune.

Only 1 in 10 dreams among men and 1 in 30 dreams among women are overtly sexual.

Sleep apnea patients, who repeatedly awaken with a gasp for air, and then fall back asleep, don't remember these episodes during the night.

Why We Dream?

Freud said, To satisfy our wishes...

- Manifest Content- Remebered story line of drem

- Latent Content- The underlying meaning of the dream

To file away memories

To develop and preserve neural pathways

To make sense of neural static

To reflect cognitive development

- REM Rebound- The tendency for REM sleep to increase following REM sleep deprivation.