Intro to psychology - basic processes: Chapter 5 - Consciousness (con't)

Electromyograph (EMG)

Records muscular activity and tension

Electrooculograph (EOG)

Records eye movements

The average length of time it takes people to fall asleep

25 minutes, depending on factors like how long it has been since the person has slept, where the person is in their circadian cycle, the amount of noise or light in the sleep environment, and the person’s age, desire to fall asleep, etc

Stage 1 non-REM sleep (con’t)

The alpha waves that probably dominated EEG activity just before falling asleep give way to lower-frequency EEG activity in which theta waves are prominent

Slow-wave sleep (SWS)

Low-frequency delta waves become prominent in EEG recordings.

REM (Rapid Eye Movement) sleep [con’t]

Was discovered accidentally in the 1950s in Nathaniel Kleitman’s lab at the University of Chicago

Sleep cycle repetition

The sleep cycle is usually repeated 4 times

Sleep cycle repetition (con’t)

The first REM period is relatively short, lasting only a few minutes. Subsequent REM periods get progressively longer, peaking at around 40–60 minutes in length

Sleep cycle repetition (III)

Most slow-wave sleep occurs early in the sleep cycle, and REM sleep tends to pile up in the second half of the sleep cycle.

Non-REM (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

Non-REM (NREM) sleep and sleep cycles

NREM intervals tend to get shorter, and descents into NREM stages usually become more shallow

Age and sleep patterns

Canadians between the ages of 15 and 24 reported the greatest sleep time, while those between 35 and 44 reported the least sleep

Age and the sleep cycle

Age can greatly alter the sleep cycle

e.g. Babies may sleep six to eight times in a 24-hour period, which consolidates as they grow

Culture and sleep

In tropical cultures, there may be “siesta hours” where shops close and activities are curtailed in the afternoon to permit people to enjoy a short midday nap and avoid working in the hottest part(s) of the day

The ascending reticular activating system (ARAS)

Consists of the afferent fibres running through the reticular formation that influence physiological arousal

Brain structures and the regulation of sleeping and waking

Activity in the pons and adjacent areas in the midbrain seem to be critical to the generation of REM sleep

Brain structures and the regulation of sleeping and waking (con’t)

Research has focused on the importance of various areas in the hypothalamus for the regulation of sleep and wakefulness

Brain structures and the regulation of sleeping and waking (III)

Specific areas in the medulla, thalamus, and basal forebrain have also been implicated in the control of sleep, and a variety of neurotransmitters are involved

The evolutionary significance of sleep

Sleep is seen in a highly diverse range of organisms, and that it appears to have evolved independently in birds and mammals suggests that it has considerable adaptive value

Effects of sleep deprivation

It can impair individuals’ attention, reaction time, motor coordination, and decision-making, and may also have negative effects on endocrine and immune system functioning

Effects of REM deprivation and slow wave sleep

It has little impact on daytime functioning and task performance, but it creates a “rebound effect,” where people spend extra time in REM periods for 1- 3 nights to make up for their REM deprivation

Sleep and memory

Sleep seems to enhance participants’ memory of specific learning activities that occurred during the day

Sleep and creative performance

REM may promote creative insights related to previous learning

Sleep loss and health

Evidence suggests that sleep loss can affect physiological processes in ways that may undermine physical health

e.g. Increases in hunger, mortality rates

How many sleep disorders are there?

83 different types of sleep disorders

Insomnia

Chronic problems in getting adequate sleep that result in daytime fatigue and impaired functioning

Insomnia (con’t)

Occurs in three basic patterns:

• Difficulty in falling asleep initially

• Difficulty in remaining asleep, and

• Persistent early-morning awakening.

Consequences of insomnia

Is associated with reduced productivity; increased absenteeism at work; an elevated risk for accidents, anxiety, and depression; and notable increases in quite a variety of serious health problems

Insomnia statistics

17% of Canadian adults (6.3 million people) suffer from it

Insomnia statistics (con’t)

The prevalence of it increases with age and is about 50% more common in women than in men

Insomnia treatments

Benzodiazepine sedatives, which were originally developed to relieve anxiety

e.g. Dalmane, Halcion, and Restoril

Insomnia treatments (con’t)

Nonbenzodiazepine sedatives, which were designed primarily for sleep problems

e.g. Ambien, Sonata, and Lunesta

Consequences of sedatives

It’s possible to overdose on sleeping pills (especially in conjunction with alcohol use), and can have carryover effects that can make people drowsy and sluggish the next day

Sleeping pill use and mortality

6.1% of the sedative users died, whereas the death rate among non-users was only 1.2%

Narcolepsy

A disease marked by sudden and irresistible onsets of sleep during normal waking periods, where a person goes directly from wakefulness into REM sleep, usually for a short period

Narcolepsy statistics

Is uncommon and seen in only about 0.05% of the population; is sometimes genetic

Sleep apnea

Frequent, reflexive gasping for air that awakens a person and disrupts sleep where a person is awakened from their sleep hundreds of times a night

Sleep apnea (con’t)

Occurs when a person literally stops breathing for a minimum of ten seconds and has loud snoring

Sleep apnea statistics

Is seen in about 8% of adults, and its prevalence is increasing, especially amongst males, older adults, postmenopausal women, obese people, and those with a genetic predisposition to the disease

Sleep apnea risks

It increases vulnerability to cardiovascular diseases and more than doubles one’s overall mortality risk

Night terrors

Abrupt awakenings from slow wave, NREM sleep, accompanied by intense autonomic arousal, remarkable accelerations of heart rate, and feelings of panic

Night terrors (con’t)

Victims typically let out a piercing cry, bolt upright, and then stare into space; panic normally fades quickly, and a return to sleep is fairly easy, with no memory of the it the next day

Night terrors statistics

Occurs mainly in adults, but they are more common in children (6 - 30%)

Somnambulism (sleepwalking)

When a person arises and wanders about while remaining asleep

Somnambulism (sleepwalking) statistics

About 15% of children exhibit it, whereas 2.5% of adults do it

Somnambulism (sleepwalking) duration

Episodes can last from a minute or 2, up to 30 minutes, and sleepwalkers may awaken during their journey, or they may return to bed without any recollection of their excursion.

Somnambulism (sleepwalking) duration (con’t)

Occurs during the first three hours of sleep, when individuals are in slow-wave sleep

Somnambulism (sleepwalking) reasons

Genetic predisposition, and episodes are associated with prior sleep deprivation and increased stress

REM sleep behaviour disorder (RBD)

Potentially troublesome dream enactments during REM periods where people may talk, yell, gesture, flail about, or leap out of bed during their REM dreams

REM sleep behaviour disorder (RBD) statistics

Occurs mostly in men, who typically begin experiencing this problem in their 50s or 60s

REM sleep behaviour disorder (RBD) cause

Deterioration in the brainstem structures that are normally responsible for immobilization during REM periods

REM sleep behaviour disorder (RBD) cause (con’t)

Drugs and alcohol, high chocolate intake, and migraine headaches

Nightmares

Anxiety-arousing dreams that lead to awakening, usually from REM sleep

Nightmares (con’t)

A person who awakens from a nightmare recalls a vivid dream and may have difficulty getting back to sleep.

Nightmares causes

Measures of an individual’s stress and well-being

Nightmares statistics

• 5% of adults have occasional trouble with them

• 10% - 50% experience them regularly

Electrocardiograph/electromyography (EKG)

A machine that records the contractions of the heart

Narcotics

Drugs derived from opium that are capable of relieving pain

Psychoanalytic theory

Understands dreams as expressions of unconscious wishes and desires.

Problem-solving theory

Sees dreams as opportunities to work through everyday challenges.

Activation-synthesis theory

Proposes that dreams are the brain's attempt to make sense of random neural firings.

Altered state of consciousness theory

Argues that when people are hypnotized, they are in different state based on changes in their brain activity.