Sleep stages and arousal theory

Physiological Mechanisms of Arousal

• Sleep can override other motives, such as hunger or sex, when one has gone without it for a lengthy period.

Learning Objectives

• The chapter will cover brain mechanisms involved in arousal.
• Properties, mechanisms, and functions of sleep will be described.
• Stress will be defined and its influence on the body discussed.
• Ways people deal with stress will be addressed.

Arousal Theory

• Yerkes-Dodson Law describes the relationship between performance and how aroused someone is.
• The Yerkes-Dodson Law is graphically represented by an inverted U-function.
• Behavior changes, as someone becomes more aroused
• Motivation results from the activation of the Central Nervous System (CNS).
• There is an optimal level of arousal for tasks
• Task-specific optimal level is not the same for all tasks.
• The inverted U does not hold for all performances, such as symbol matching.
• In 1937, Bremer found through studies that the structures (brain stem/pons) between cuts are critical for moving from asleep to awake.
• Encephale isole (isolated brain) shows a normal sleep-wake cycle.
• Cerveau isole (isolated forebrain) shows sleep-wake cycle abolished, constant sleep
• EEG is the electroencephalogram
• Alpha waves are synchronous patterns present when resting
• Beta waves are desynchronized patterns when alert, attentive, and aroused.

Reticular Activating System (RAS)

• The RAS is a group of neurons in the brain stem.
• Electrical stimulation of the RAS results in beta waves due to stimulation from external stimuli
• RAS receives sensory input
• Lindsley discovered the RAS in the 1950s
• Fibers from the RAS extend to the cortex.
• RAS is responsible for arousing an animal from sleep.
• RAS dictates where in the arousal continuum we will focus and what to pay attention to.

Hebb's Theory

• Sensory information serves two jobs: provide information (cue function) and arouse the animal (arousal function).
• Motivation equals activation of the RAS.
• Upstream equals get ready.
• Downstream equals thoughts.

Psychophysiological Measures

• Measuring arousal is multidimensional (Lacey, 1967)
• Few correlations exist between brain activity and behavior.
• Atropine can cause an EEG to appear sleepy while the cat/dog is awake and physostigmine causes the EEG to appear awake while the cat/dog is sleepy.
• Comatose patients can have normal EEG readings, whereas normal people may have sleeplike EEGs at times.
• The three types of arousal are: Behavioral, Autonomic, and Cortical.
• Behavioral arousal is enacted initiated animal or person.
• Autonomic arousal is changes in bodily functions.
• Cortical arousal is desynchronized, fast brain waves.

Criticisms of Arousal Theory

• There is no strong relationship between behavioral, cortical, and autonomic arousal measures.
• Cortical arousal is not always related to motivated or emotional states
• There is belief that motivation might be influenced by other things than physiological mechanisms

Sleep

• Sleep is its own type of behavior and not the lack of behavior.
• Individual differences exist in the amount of sleep someone needs
• Sleep can also be a motivating factor.
• Lack of sleep can cause attention deficits, problems with immune function, and even death.
• Problems sustaining performance may occur after deprived of sleep

Sleep: General Properties

• Dement (1972) showed that sleep occurs when we are least efficient.
• Circadian Rhythms are cyclic changes that occur every 24 hours.
• Sleep has two separate processes: Homeostatic and Circadian.
• With the Homeostatic process, longer awake equals more likely to sleep
• The Circadian process tells us when to wake up.

Types of Sleep

• Unihemispheric slow-wave sleep (USWS) is when one half of the brain sleeps at a time.
• It is seen in whales and birds.
• Rapid-Eye Movement (REM) sleep and non-REM sleep are present in all other mammals.

Stages of Sleep

• "Drifting off" is the gradual transition between stages of sleep
• Relaxed wakefulness is the first sleep stage
• Stages 1-4 are moving from wakefulness to sleep, non-REM sleep
• Stage 5 is REM sleep
• A usual pattern through sleep stages is 1, 2, 3, 4, 3, 2, 5.

Stages of Sleep: Stage 1

• People in this stage exhibit relaxed wakefulness.
• Theta wave activity is seen

Stages of Sleep: Stage 2

• Sleep spindles (14 Hz/sec) and K-complexes are seen.

Stages of Sleep: Stage 3

• Delta waves occur 20-50% of the time in this stage.
• This is also called slow-wave sleep due to high amplitude and low delta waves.

Stages of Sleep: Stage 4

• Delta waves occur more that 50% of the time in this stage.
• The amount of delta waves decrease with age.
• Decline in delta waves is sharp after age 30.
• Delta waves disappear in some people after they turn 50.

Stages of Sleep: Stage 5

• This stage marks the beginning of REM sleep.
• It has a mix of theta, alpha, and beta waves.
• There is low muscle tone due to inhibition of motor neurons
• This is the stage where one typically dreams
• Time in this stage increases throughout the night.

Non-REM vs. REM

• Non-REM sleep is restorative and allows the body to rebuild resources.

• Reduction of stages 3 and 4 sleep are seen in healthy older people

• Forward shifting of REM sleep earlier in the night may occur

• Snoring occurs in Non-REM sleep

• Non-REM sleep is typified by nonemotional, random thoughts (like when awake)

• REM sleep organizes connections in brain and is when dreaming occurs

• REM sleep is typified by emotionally-loaded, lifelike dreams that are sometimes bizarre

• REM sleep is also known as paradoxical sleep.

Total Sleep

• In total sleep, 5% of time is spent in stage 1.
• 50% of time is spent in stage 2
• 6% of time is spent in stage 3
• 14% of time is spent in stage 4
• 25% of time is spent in stage 5

Dreams

• Research shows that everyone dreams.
• You are more likely to remember your dreams, if awakened during REM sleep
• Dreams are brief and last longer toward the end of sleep.
• Dream content depends on time.
• Early dreams often repeat the previous day.
• Later dreams are of stored memories.
• Around 65% of dreams are of negative emotion

Dreams: Domhoff (2001)

• Dream content depends on time.
• Neurocognitive theory of dreams states that dreaming is "a developmental cognitive achievement that depends upon the maturation and maintenance of a specific network of forebrain structures”
• Continuity principle states personal concerns during the day also appear in dreams.
• Repetition principle states characters, settings, and social interactions recur in dreams across time.

Dreams: Revonsuo (2000)

• Threat Simulation Theory states that dreaming simulates threats, allowing us to rehearse perceiving and avoiding them.
• Greater instances of negative emotion/aggression are present in dreams.
• Children dream about wild animals more often than do adults.

Sleep Deprivation

• The effect of sleep deprivation depends on the task.
• Short tasks can be performed if one is sufficiently motivated, regardless of sleep
• Performance on long, boring tasks requires high motivation.

Dream Deprivation

• REM pressure: subjects were woken more constantly to deprive them of REM sleep. Dement found sleep deprived test subjects appeared irritable/anxious and had trouble concentrating but this has not been replicated.
• REM rebound: when dream-deprived subjects could sleep normally, they dreamed much more than normal, lasting for several days.

REM Deprivation

• Drug usage can cause REM deprivation.
• Barbituates can cause REM deprivation.
• Amphetamines can cause REM deprivation.
• Alcohol can cause REM deprivation.
• Withdrawal can cause REM deprivation: delirium tremens, or DTs

Physiology of Sleep

• During NREM sleep, blood pressure, heart rate, and respiration decrease.
• During NREM sleep, veins/arteries are dilated (vasodilation).
• During REM sleep, blood pressure, heart rate, and respiration increase.
• During REM sleep, increased flow of blood to the brain.

Arousal Neurotransmitters

• Acetylcholine increases general arousal in the cortex.
• Norepinephrine has high production during waking hours and is responsible for general arousal.
• Serotonin is most active during waking hours.
• Histamine has high levels during waking hours.
• Orexin is implicated in arousal.

Sleep Neurotransmitter

• Ventrolateral preoptic (VLPO) area is responsible for delta wave sleep
• GABA (gamma-aminobutryric acid) is produced by VLPO
• It inhibits the regions that are associated with arousal such as: Locus coerulus, Raphe, Tuberomammilary nucleus, and Lateral hypothalamus.

Adenosine, the "Sleep Chemical"

• Pieron, early 1900s, tested spinal fluid from sleep-deprived dogs and injected into control dogs
• The control dogs slept more.
• Pappenheimer (1976) tested spinal fluid from sleep-deprived goats and injected into cats.
• The cats were drowsy.
• Adenosine is produced by the brain during waking hours and inhibits neurons for arousal.
• Caffeine and theophylline block adenosine receptors, causing one to stay awake.

Functions of Sleep

• Restorative function: sleep restores body and mind
• Brain organization: sleep organizes brain function
• Programming/consolidation of memories: sleep helps programming and consolidate memories
• Storage of complex associative information: sleep allows this to be stored

Stress

• Stress happens when the body is forced to cope with or adapt to a changed situation.
• Stress can be beneficial, due to “Optimal levels"
• Stress can be psychological or physical.
• Stress acts as a Homeostatic function.
• You are able to react less to a threat when you have total control

Endocrine System

• Glands throughout the body secrete hormones into the blood stream
• Hormones are chemical signals which regulate organs
• Major glands of the endocrine system: pituitary & adrenal glands

Pituitary Gland

• This gland is also known as the "Master gland."
• It's located at the base of the brain
• The Hypothalamus releases hormones to cause the pituitary gland to work

Adrenal Glands

• These glands are located on top of kidneys.
• The Adrenal Cortex is made up of Cortisol and Aldosterone.
• Cortisol regulates blood sugar levels
• Aldosterone regulates water/electrolyte balances
• The adrenal medulla releases Epinephrine/Norepinephrine, regulating blood pressure and fuel metabolism.

Stress Mechanism

• Encountering a stressor (internal/external) activates the hypothalamus.
• The activated hypothalamus activates Sympathetic Nervous System
• This activated Hypothalamus then secretes CRH and stimulates Piluitary gland
• The Piluitary gland then secretes ACHT.
• Stimulates Adrenal Medulla
• Stimulates Adrenal Cortex
• Epi/Norepi releases from hypothalamus.
• Cortisol/Aldosterone releases from Piluitary gland.

General Adaptation Syndrome

• This consists of 3 stages: Alarm reaction, Resistance, and Exhaustion.
• Alarm reaction helps prepare the entire body for attack (epinephrine).
• Resistance mobilizes the body parts that are under attack.
• Resistance also increases ability to adapt.
• Stressor becomes general again in Exhaustion stage.
• Additional resources are then brought to the site of stressor
• Death if unresolved =

General Adaptation Syndrome

• This consists of 3 stages: Alarm reaction, Resistance, and Exhaustion.
• Designed to eliminate or contain the stressing element
• Can respond to anxiety, loud noises, or crowding
• The syndrome gets overactive and causes: Ulcers, high blood pressure, kidney disease, inflammation, allergies

Life Change, Stress, and Illness

• Life events increase susceptibility to physical and mental illness.
• Illness clusters can be a sign of stress such as colds/exams.
• Emotional insulation also suggests stress

Buffers to Stress

• Hardiness, Commitment, Control, Challenge, and Exercise
• Social Support
• Sex-role orientation
• Self-complexity
• Humor
• Optimism

Buffers

• Social and emotional support theory
• Explanatory style
• Optomistic vs. pesimistic
• Style or expression
• knowledge
• Emotional insulation
• Looking beyond the moment
• alternate plans

Health Psychology

• Baum & Posluszny (1999)
• Behavior influences health 3 ways:
• biological changes
• Behavioral Risk
• Impaired behavior

Pyschoneuroimmunology

Looking at relationships between behavior, nervous system & and immune system 3 types:

• Immune responses
• Psychosocial factors
• Emotion

Psychoneuroimmunology

• Acute Stressors
• short lived stressors
• Adaptive & maladaptive stressors
• Enhances immune response

Psychoneuroimmunology

• chronic stressors
• Long lived stressors
• Maladpative stressors
• Immunosupression

Effects:

Placebo inhibits an insert

• Placebo response
• The perceive change created by placebo
• Influenced by persons expectation
• Placebo responders vs non responders
• Desire-expectation model
• Desire-motivation to feel differently
• Expectation belief that the treatment will cause a different of feeling

Sexual Arousal Stages

• Vasocontrition
• contraints on of bloods
• Myotonia increase in muscle tone
• Stages of sexual response cycle -Excitement phisical stituli
• Plato increase intensity to prepare for organism -Orgasm- climaz, gender differences -Resolution- refractory
• perios for men

Sexaul Arousal bodily changes

• Female
• Carpopedal spam- voluntary contractions of hand and feet
• Sex flush redding of fushl

Male:

-2 stage process organism and e generation

Sexaul Arousal bodily change

• Saxoul desire
  • Appetitive
• Desire must come before the arusal
  • Hypoactive Saxul desire
• Looong sexual appetite
• become uninterested in sexual behavior orasam vs satisfaction -Desire excitement plato orasam solution satisfaction refractory perid