Chapter 3: Physiological Mechanisms of Arousal

CHAPTER 3: PHYSIOLOGICAL MECHANISMS OF AROUSAL Hollie Pellosmaa, Ph.D. “Anyone who has gone for any lengthy period of time without sleep realizes that sleep can become an overpowering motive, easily overriding such motives as hunger or sex.” (p. 68) CHAPTER 3: LEARNING OBJECTIVES  Disc...

CHAPTER 3: PHYSIOLOGICAL MECHANISMS OF AROUSAL Hollie Pellosmaa, Ph.D. “Anyone who has gone for any lengthy period of time without sleep realizes that sleep can become an overpowering motive, easily overriding such motives as hunger or sex.” (p. 68) CHAPTER 3: LEARNING OBJECTIVES  Discuss which brain mechanisms are involved in arousal  Describe the properties, mechanisms, and functions of sleep  Define stress, and discuss how to influences the body  Discuss the ways people deal with stress AROUSAL THEORY  Yerkes-Dodson Law: inverted U-function; describes the relationship between performance and arousal AROUSAL THEORY  Behavior will change as we become more aroused  Motivation is the result of activation of the CNS  Optimal level of arousal for a task  Task-specific  optimal level is not the same for all tasks  Inverted U does not hold for all performances (e.g. symbol matching) AROUSAL THEORY  Bremer, 1937  Encephale isole (isolated brain): Normal sleep-wake cycle  Cerveau isole (isolated forebrain): Sleep- wake cycle is abolished, constant sleep  Suggests that the structures (brain stem/pons) between the cuts are critical for moving from asleep  awake AROUSAL THEORY  EEG: Electroencephalogram  Alpha waves: synchronous pattern; resting  Beta waves: desynchronized pattern; alert, attentive, and aroused RETICULAR ACTIVATING SYSTEM (RAS)  Group of neurons in the brain stem  Electrical stimulation of the RAS = beta waves = stimulation from external stimuli RETICULAR ACTIVATING SYSTEM (RAS)  Receives sensory input  Lindsley, 1950s  Fibers cortex  RAS arouses the animal from sleep  wakefulness  Dictates where were are in the arousal continuum  Dictates what we pay attention to HEBB’S THEORY  Sensory information has 2 jobs:  Provide information (“cue function”)  Arouse the animal (“arousal function”)  Motivation = activation of the RAS  Upstream = get ready  Downstream = thoughts? PSYCHOPHYSIOLOGICAL MEASURES  Few correlations between brain activity and behavior  Atropine (EEG sleepy, cat/dog awake) vs. Physostigmine (EEG awake, cat/dog sleepy)  Comatose patients, normal EEG vs. Normal responding sometimes seen with sleeplike EEGs  Lacey, 1967 – arousal is multidimensional  3 different types of arousal:  Behavioral arousal: initiated by animal/person  Autonomic arousal: changes in bodily functions  Cortical arousal: desynchronized, fast brain waves CRITICISMS OF AROUSAL THEORY  No strong relationship between behavioral, cortical, and autonomic arousal measures  Cortical arousal is not always related to motivated or emotional states  Motivation might be influenced by other things than physiological mechanisms SLEEP  Sleep is a type of behavior, not the lack of behavior  Individual differences in amount needed  Sleep can also be a motivating factor  Lack of sleep causes attention deficits, problems with immune function or even death  Problems sustaining performance after deprived SLEEP: GENERAL PROPERTIES  Dement (1972)  Sleep = when we are least efficient  Circadian rhythms: cyclic changes that occur every 24 hours  Sleep has 2 separate processes:  Homeostatic – longer we’re awake, more likely to sleep  Circadian – tells us when to wake up TYPES OF SLEEP  Unihemispheric slow-wave sleep (USWS): one half of the brain sleeps at a time  Seen in whales and birds  Other Mammals: Rapid-Eye Movement (REM) sleep vs. non-REM sleep STAGES OF SLEEP  “Drifting off” – gradual transition between stages:  Relaxed wakefulness  Stage 1 Moving from wakefulness  sleep  Stage 2 non-REM  Stage 3 sleep  Stage 4  Stage 5 – REM sleep  Pattern  1, 2, 3, 4, 3, 2, 5 STAGES OF SLEEP: STAGE 1  Relaxed wakefulness  Stage 1  theata wave activity STAGES OF SLEEP: STAGE 2  Sleep spindles (14 Hz/sec) and K-complexes STAGES OF SLEEP: STAGE 3  Delta waves occurring 20-50% of the time  Slow-wave sleep: high amplitude, low delta waves STAGES OF SLEEP: STAGE 4  Delta waves occurring > 50% of the time  Decreases with age  Sharp decline after 30  Disappearing in some people 50+ STAGES OF SLEEP: STAGE 5  REM sleep  Mix of theta, alpha, and beta waves  Low muscle tone due to inhibition of motor neurons  Typically, dreaming  Time in this stage increases throughout the night NON-REM VS. REM Non-REM REM  Restorative function  Organizes connections in brain  Allow body to rebuild resources  Dreaming  Reduction of stages 3 and 4 in healthy older people  ~Bizarre, emotionally-loaded,  Forward shifting of REM sleep earlier in the lifelike night?  “Paradoxical sleep”  Snoring  ~Nonemotional, random thoughts (like when awake) TOTAL SLEEP  Stage 1 = 5%  Stage 2 = 50%  Stage 3 = 6%  Stage 4 = 14%  Stage 5 = 25% DREAMS  Research shows that we all dream  More likely to remember them if we are awakened during REM sleep  Dreams are usually brief  Longer (even up to an hour) toward the end of sleep  Content depends on time  Early in night/sleep = previous day  Later in night/sleep = stored memories  Negative emotions  ~65% DREAMS: DOMHOFF (2001)  Neurocognitive theory of dreams: “a developmental cognitive achievement that depends upon the maturation and maintenance of a specific network of forebrain structures”  Continuity principle: personal concerns during the day also appear in dreams  Repetition principle: characters, settings, social interactions, etc., recur in dreams across time DREAMS: REVONSUO (2000)  Threat Simulation Theory: dreaming functions to simulate threats, allowing us to rehearse perceiving and avoiding threats  Support:  Greater instances of negative emotion/aggression  Children dream about wild animals more often than do adults SLEEP DEPRIVATION  Depends on type of task  Short tasks with sufficient motivation  Long, boring tasks requiring high motivation DREAM DEPRIVATION  REM pressure: subjects had to be woken more constantly to deprive them of REM sleep  Dement found they 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  Can last for several days REM DEPRIVATION  Drug usage  Cause REM deprivation:  Barbituates  Amphetamines  Alcohol  Withdrawal: delirium tremens, or DTs PHYSIOLOGY OF SLEEP  During NREM sleep:  Blood pressure, heart rate, and respiration  Veins/arteries dilate (vasodilation)  During REM sleep:  Blood pressure, heart rate, respiration  Increased flow of blood to brain AROUSAL NEUROTRANSMITTERS  Acetylcholine  Increases general arousal in the  Histamine cortex  High levels during waking  Norepinephrine  Orexin  High production during waking  Implicated in arousal  Serotonin  Most active during waking SLEEP NEUROTRANSMITTER  Ventrolateral preoptic (VLPO) area  Delta wave sleep  GABA (gamma-aminobutryric acid)  Produced by VLPO  Inhibit the regions that are associated with arousal  Locus coerulus  Raphe  Tuberomammilary nucleus  Lateral hypothalamus ADENOSINE, THE “SLEEP CHEMICAL”  Pieron, early 1900s  CSF sleep-deprived dogs  control dogs  Control dogs slept more  Pappenheimer (1976)  CSF goats  cats  Cats were drowsy  Adenosine  Produced by brain during waking hours  Inhibitory  neurons for arousal ADENOSINE, THE “SLEEP CHEMICAL”  Support: caffeine and theophylline block adenosine receptors, causing you to stay awake FUNCTIONS OF SLEEP  Restorative function  Brain organization  Programming/consolidation of memories  Storage of complex associative information FUNCTIONS OF SLEEP STRESS  Stress: happens when the body is forced to cope with or adapt to a changed situation  Can be good!  “Optimal levels” of stress  Psychological vs. physical  Homeostatic function  Having control helps you react LESS to a threat ENDOCRINE SYSTEM  Glands throughout the body that secrete hormones into the blood stream  Hormones are chemical signals which regulate organs  Major glands: pituitary & adrenal PITUITARY GLAND  “Master gland”  Located at base of brain  Hypothalamus – releases hormones to cause the pituitary gland to work ADRENAL GLANDS  Located on top of kidneys  Adrenal cortex  Cortisol  regulates blood sugar  Aldosterone  water/electrolyte balance  Adrenal medulla  Epinephrine/Norepinephrine  blood pressure & fuel metabolism STRESS MECHANISM GENERAL ADAPTATION SYNDROME  3 Stages  Alarm reaction  Help prepare the entire body for attack (epinephrine)  Resistance  Mobilizes just the body parts that are under attack  Ability to adapt is increased  Exhaustion  Stressor becomes general again  Additional resources brought to site of stressor  If unresolved = death GENERAL ADAPTATION SYNDROME GENERAL ADAPTATION SYNDROME  “Designed to eliminate or contain the stressing element”  Can respond to anxiety, loud noises, or crowding  If overactive, can cause:  Ulcers, high blood pressure, kidney disease, inflammation, allergies LIFE CHANGE, STRESS, AND ILLNESS  Life events  susceptibility to physical and mental illness  Illness clusters  Colds/exams  Suggests emotional insulation SOCIAL READJUSTMENT RATING SCALE (SRRS) LIFE EVENTS SCALE PSS-10 BUFFERS TO STRESS  Hardiness  Commitment further support  Control that  Challenge controllability is  Exercise an important  Social support factor  Sex-role orientation  Self-complexity  Humor  Optimism BUFFERS  Social support theory  Explanatory style  Optimistic vs. pessimistic  Expressive style  Humor  Knowledge  Emotional insulation  Looking beyond the moment  Alternate plans HEALTH PSYCHOLOGY  Baum & Posluszny (1999)  Behavior influences health 3 ways: 1. Biological Changes 2. Behavioral Risk 3. Illness Behaviors PSYCHONEUROIMMUNOLOGY  Looks at relationships between behavior, nervous system, and the immune system  3 types: 1. Immune responses 2. Psychosocial factors 3. Emotion PSYCHONEUROIMMUNOLOGY  Acute stressors  Short-lived stressors  Adaptive and maladaptive stressors  Enhances immune response PSYCHONEUROIMMUNOLOGY  Chronic stressors  Long-lived stressors  Maladaptive stressors  Immunosuppression PLACEBO EFFECTS  Placebo  inert substance that people think makes them feel better  Placebo response  the perceived change created by a placebo  Influenced by person’s expectations, desires (motivation), emotion, past effects/memories  Placebo responders vs. non-responders  Desire-expectation model  Desire = motivation to feel differently  Expectation = belief that the treatment will cause a difference in feeling SEXUAL AROUSAL: STAGES  Vasocongestion: concentration of blood  Myotonia: increase in muscle tone  Stages of the sexual response cycle  Excitement – physical stimuli  Plateau – increase in intensity to prepare for orgasm  Orgasm – climax, gender differences  Resolution – refractory period for men SEXUAL AROUSAL: BODILY CHANGES  Female  Carpopedal spasm – involuntary contractions of hands and feet  Sex flush – reddening of flush  Male  Two-stage process (orgasm and ejaculation) SEXUAL AROUSAL  Sexual desire  ~appetite  Desire must come before arousal  Hypoactive sexual desire  Losing sexual appetites  Become uninterested in sexual behavior  Orgasm vs. satisfaction  Desire  excitement  plateau  orgasm  resolution  satisfaction  refractory period HAVE A GREAT WEEK!