Ch. 17 - emotion, stress, and health PDF

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Ch. 17 Biopsychology of Emotion, Stress, and Health LO 17 Early Landmarks in the Biopsychological Investigation of Emotion THEORY OF THE EVOLUTION OF EMOTION Darwin developed a theory of the evolution of emotional expression that was composed of 3 main ideas o Expressions of emotion evolve from beha...

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Ch. 17 – Biopsychology of Emotion, Stress, and Health

LO 17.1 Early Landmarks in the Biopsychological Investigation of Emotion DARWIN’S THEORY OF THE EVOLUTION OF EMOTION  Darwin developed a theory of the evolution of emotional expression that was composed of 3 main ideas = o Expressions of emotion evolve from behaviors that indicate what an animal is likely to do next. o If the signals provided by such behaviors benefit the animal that displays them, they will evolve in ways that enhance their communicative function, and their original function may be lost. o Opposite messages are often signaled by opposite movements and postures, an idea called the principle of antithesis.  Accounts for threat displays – aggression v. submission examples JAMES-LANGE AND CANNON-BARD THEORIES James-Lange Theory Cannon-Bard Theory  Autonomic activity and behavior that are  Emotional stimuli have two independent excitatory effects: they excite both the triggered by the emotional event (e.g., feeling of emotion in the brain and the rapid heartbeat and running away) produce expression of emotion in the autonomic the feeling of emotion – not vice versa  Emotional expression DEPEND entirely on and somatic nervous system. feedback from autonomic and somatic  Emotional expression and emotional expression are PARALLEL processes that nervous system activity. have NO DIRECT CAUSAL RELATION.  Emotional experience is totally INDEPENDENT of such feedback.  BOTH are INCORRECT; Today’s accepted view – Modern Biopsychological View  Autonomic and somatic feedback is NOT necessary to experience emotion. o

Though there are some dampening of certain emotional experiences

SHAM RAGE  1920’s = Bard discovered that decorticate cats (cortex removed) – respond aggressively to the slightest provocation.  Sham rage = exaggerated, poorly directed aggressive responses of decorticate animals o Occurs either when – cerebral hemispheres have been removed down to the hypothalamus or even to the extent when the hypothalamus is removed.  Conclusions: hypothalamus is critical for the expression of aggressive responses and the function of the cortex is to inhibit and direct these responses. LIMBIC SYSTEM AND EMOTION  1937 – Papez proposed that emotional expression is controlled by the limbic system  revised and expanded by Paul MacLean (1952) to limbic system theory of emotion. Limbic system contains = amygdala, mammillary body, hippocampus,  fornix, cingulate cortex, septum, olfactory bulb, and hypothalamus. KLUVER-BUCY SYNDROME  1939, Kluver and Bucy observed a syndrome in monkeys whose anterior temporal lobes had been removed.  Symptoms Included: o Consumption of almost anything that is edible

Ch. 17 – Biopsychology of Emotion, Stress, and Health

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o Increased sexual activity often directed an inappropriate objects o Tendency to repeatedly investigate familiar objects o Tendency to investigate objects with the mouth o LACK OF FEAR. Monkeys who were difficult to handle became tame after the surgery Seems to be a result of damage to the amygdala

LO 17.2 Emotions and the Autonomic Nervous System  Research on ANS focuses on 2 things: (1) degree to which specific patterns of ANS activity are associated with specific emotions, and (2) the effectiveness of ANS measures in polygraphy (lie detection). EMOTIONAL SPECIFICITY OF THE AUTONOMIC NERVOUS SYSTEM  James-Lange theory = different emotional stimuli induce DIFFERENT PATTERNS of ANS activity  producing different emotional experiences.  Cannon-Bard theory = ALL emotional stimuli produce the SAME general patter of sympathetic activation  prepares organism for action  Experimental evidence = specificity of ANS reactions lies between the extremes of total specificity and total generality. POLYGRAPHY – “lie detector test”  Problem: rarely possible in real-life situations to know for certain if the suspect is guilty or innocent.  Mock-crime procedure = volunteers participate in a mock crime and are then subjected t o a polygraph test by an examiner who is unaware of their “guilt” or “innocence.” o Control-question technique = physiological response to the target question is compared with the physiological responses to control questions (whose answers are known).  Polygraphy detects ANS activity, NOT LIES.  Guilty-knowledge technique (concealed information test) = o Polygrapher has a piece of information concerning the crime that would be known only to the guilty person.  Polygraphy assesses the suspect’s reaction to a list of actual and contrived details of the crime. o Innocent suspects react in the same way; the guilty react differently. LO 17.3 Emotions and Facial Expressions  Facial expressions are UNIVERSAL  (Ekman and Friesen) 6 primary emotions on facial expressions = surprise, anger, sadness, disgust, fear, and happiness. o Facial expressions of genuine emotion are composed of mixtures of these 6 primaries  Facial feedback hypothesis = our facial expressions influence our emotional experience VOLUNTARY CONTROL OF VACIAL EXPRESSION  2 ways of distinguishing true expressions from false ones (Ekman, 1985) o (1) Microexpressions of the real emotion often break through the false ones.  Last only 0.05 seconds, but is detectable o (2) Subtle differences between genuine facial expressions and false ones (by skilled observation).  1862 = Duchenne observed 2 facial muscles contracted during genuine smiles o Orbicularis oculi = encircles the eye and pulls the skin form the cheeks and forehead toward the eyeball; controlled ONLY BY GENUINE PLEASURE o Zygomaticus major = pulls the lips corners up; controlled VOLUNTARILY  Duchenne smile = genuine smile (with contractions from both muscles). FACIAL EXPRESSIONS: CURRENT PERSPECTIVES 1. Ekman’s 6 primary facial expressions of emotion rarely occur in PURE FORM

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Ch. 17 – Biopsychology of Emotion, Stress, and Health

2. Existence of other primary emotions has been recognized 3. BODY CUES play a major role in expressions of emotion 4. Ekman’s 6 primary facial expressions may not be as universal as originally believed. FEAR, DEFENSE, AND AGGRESSION o Fear = the emotional reaction to threat; motivating force for defensive behaviors o Defensive behavior = primary function is to protect the organism from threat or harm o Aggressive behavior = primary function is to threaten or harm LO 17.4 Types of Aggressive and Defensive Behaviors o Numerous detailed descriptions of aggressive and defensive behaviors research by Blanchards, Pellis and collegeus, and other biopsychologists  distinguished categories o 3 crieria basis for categories of aggressive and defensive behaviors o Their topography (form) o The situations that elict them o Apparent function o Target-site concept = the idea that the aggressive and defensive behaviors of an animal are often designed to attack specific sites on the body of another animal while protecting specific sites on its own. Table 17.2 Categories of Aggressive and Defensive Behaviors in Rats Predatory The stalking and killing of members of other species for the purpose of eating Aggressive Aggression them. Rats kill prey, such as mice and frogs, by delivering bites to the back of Behaviors the neck. Social Unprovoked aggressive behavior that is directed at a conspecific (member of Aggression the same species) for the purposes of establishing, altering, or mainting a social hierarchy. In mammals, occurs primarily among males. In rats, characterized by = piloerection, lateral attack, and bites directed at the defendr’s back. Intraspecific Defense against social aggression. In rats = freezing and flight; behaviors to Defensive Defense protect the back from bites. Behaviors Defensive Attacks that are lauched by animals when they are cornered by theretening Attacks members of their own or other spcies. In rats = lunging, shrieking, and biting attacks that are usually directed at the face of the attacker Freezing To avoid attack. If a human approahces a wild rat, it will often freeze until the and Flight human penetrates its safety zone  explode into flight Maternal The behaviors by which mothers protect their young. Defensive Similar to male social aggression in appearnce Behaviors Risk Behaviors performed to obtain specific information that helps them defend Assessment themselves more effecitvely. For example, rats that have been chased by a cat into their burrow do not emerge until they’ve spent considerable time at the entrance scanning the surrounding environment. Defensive Rats and other rodents spray sand and dirt ahead with their forepaws to bury Burying dangerous objects in their environment, drive off predators, and construct barriers in burrows. LO 17.5 Aggression and Testosterone  Major Conclusions (Soma and his colleagues) =

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Ch. 17 – Biopsychology of Emotion, Stress, and Health

Testosterone increases social aggression in the males of many species; aggression is largely abolished by castration in these same species. o In some species, castration has no effect on social aggression; in still others, castration reduces social aggression during the breeding season but not at other times. o The relation between aggression and testosterone levels is difficult to interpret because engaging in aggressive activity can itself increase testosterone levels o The blood level of testosterone, which is the only measure used in many studies, is not the best measure. What matters more at the testosterone levels in the relevant areas of the brain. In human males (more complicated) and evidence is unclear Lack of strong evidence of the involvement of testosterone in human aggression could mean that hormonal and neural regulation of aggression in humans differs from that in many other mammalian species. ALSO, most seemingly aggressive outbursts in humans are overreactions to real/perceived thread, and more appropriately viewed as defensive attack (NOT RELATED to testosterone) o

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NEURAL MECHANISMS OF FEAR CONDITIONING  Fear conditioning = the establishment of fear in response to a previously neutral stimulus (the conditioned stimulus) by presenting it, usually several times, before the delivery of an aversive stimulus (the unconditional stimulus). LO 17.6 Amygdala and Fear Conditioning  LeDoux and colleges – looked for the neural mechanisms of auditory fear conditioning (fear conditioning that uses a sound as a conditional stimulus) by making lesions in the auditory pathways of rats. o Bilateral lesions to medial geniculate nucleus (auditory relay nucleus of the thalamus) >> blocked fear conditioning to tone o Bilateral lesions to auditory cortex >> did NOT block fear conditioning  2 pathways from the medial geniculate nucleus (MGN) to the amygdala o DIRECT = MGN  amygdala  Amygdala receives input from all sensory systems, and it is believed to be the structure in which the emotional significance of sensory signals is learned and retained. o INDIRECT = MGN  auditory cortex  amygdala LO17.7 Contextual Fear Conditioning and the Hippocampus  Contextual fear conditioning = process by which benign contexts come to elicit fear through their association with fear-inducing stimuli  Hippocampus – key role in memory for spatial location  Bilateral hippocampal lesions block the subsequent development of a fear response to a context without blocking the development of a fear response to the explicit conditional stimulus

LO 17.8 Amygdala Complex and Fear Conditioning

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Amygdala complex = the amygdala is NOT a single structure, it is actually composed of a dozen or so major nuclei – subdivided into subnuclei (structurally distinct, different connections and functions). Lateral nucleus of the amygdala is critically involved in the acquisition, storage, and expression of conditioned fear. o Prefrontal cortex – thought to act on the lateral nucleus of the amygdala to SUPPRESS conditioned fear. o Hippocampus – interact with parts of the amygdala to mediate learning about the context of fear-related events. The amygdala is thought to control defensive behavior via outputs from the central nucleus of the amygdala.

BRAIN MECHANISMS OF HUMAN EMOTION LO 17.9 Cognitive Neuroscience of Emotion 3 fundamental findings 1. Brain activity associated with each human emotions is diffuse – there is not a center for each emotion – think of it as a MOSAIC for locations of brain mechanisms of emotion. 2. There is virtually always activity in motor and sensory cortices when a person experiences an emotion or empathizes with a person experiencing an emotion. a. Embodiment of emotions 3. Similar patterns of brain activity tend to be recorded when a person experiences an emotion, imagines that emotion, or sees somebody else experience that emotion. LO 17.10 Amygdala and Human Emotion  Amygdalae may play a role in evaluating the emotional significance of situations.  Urbach-Wiethe disease = a genetic disorder that often results in calcification (hardening by conversion to calcium carbonate, the main component of bone) of the amygdala and surrounding anterior medial temporal-lobe structures in both hemispheres o One Urbach-Wiethe patient with bilateral amygdalar damage  lost ability to recognize facial expressions of fear. LO 17.11 Medial Prefrontal Lobes and Human Emotion  Medial portions of the prefrontal lobes = sites of emotion-cognition interaction that have received the most attention.  Many studies of medial prefrontal lobe activity employ: o Suppression paradigms = participants are directed to inhibit their emotional reactions to unpleasant films or pictures o Reappraisal paradigms = participants are instructed to reinterpret a picture to change their emotional reaction to it. o Results: medial prefrontal lobes active in both paradigms; seem to exert their cognitive control of emotion by interacting with the amygdala.  Theories to specific functions = (maybe some or all) o Monitor difference between outcome and expectancy o Encode stimulus value over time o Predict the likelihood of error o Mediate the conscious awareness of emotional stimuli o Mediate social decision making

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Kawasaki and colleges = used microelectrodes to record 276 neurons in the anterior cingulate cortices (part of the medial prefrontal cortex) – 56 responded most strongly o Findings = confirms the link with medial prefrontal lobes with negative emotions  Also shows that not all neurons in the area perform the same function – neurons directly involved in emotional processing appear to be sparse and widely distributed in the human medial prefrontal lobes.

LO 17.12 Lateralization of Emotion  Lateralized emotions = meaning, that the left and right cerebral hemispheres are specialized to perform different emotional functions.  2 most prominent theories = o The right-hemisphere model of the cerebral lateralization of emotion holds that the right hemisphere is specialized for all aspects of emotional processing: perception, expression, and experience of emotion. o The valence model proposes that the right hemisphere is specialized for processing negative emotion and the left hemisphere is specialized for processing positive emotion.  Both theories are not supported by evidence; too general  Asymmetry of facial expressions = in most people, each facial expression begins on the left side. o Implies right-hemisphere dominance for facial expressions. LO 17.13 Neural Mechanisms of Human Emotion: Current Perspectives  Emotional situations produce widespread increases in cerebral activity, not just in the amygdalae and prefrontal cortex.  All brain areas activated by emotional stimuli are also activated during other psychological processes  No brain structure has been invariably linked to a particular emotion  The same emotional stimuli often activate different areas in different people STRESS AND HEALTH LO 17.14 the Stress Response  Hans Selye (1950’s) = emphasized the dual nature in the stress response – adaptive and maladaptive  Modern theory of stress = o Anterior-pituitary adrenal-cortex system o Sympathetic nervous system adrenal-medulla  Major feature of Selye’s theory – assertion that both physical and psychological stressors induce the same general stress response.  Stress responses are complex and varied; exact response depends on the…. o Stressor, timing, nature of the stressed person, and how the stressed person reacts to the stressor.  1990’s discovery = stressors produce inflammatory responses o Notably, stressors produce an INCREASE in blood levels of cytokines – a group of peptide hormones that are released by many cells and participate in a variety of physiological and immunological responses.  causes inflammation and fever o Cytokines are classified as adrenal hormones LO 17.15 Animal Models of Stress

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Ch. 17 – Biopsychology of Emotion, Stress, and Health

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Animal models of stress – involving social threats from conspecifics (members of the same species) Subordination stress = when conspecific threat becomes an enduring feature of daily life. o most readily studied in social species that form dominance hierarchies o subordinate male = attack juveniles, have smaller testes, shorter life spans, lower blood levels of testosterone, and higher blood levels of glucocorticoids subordination stress  parallels with “bullying” in human terms

LO 17.16 Psychosomatic Disorders: The Case of Gastric Ulcers  psychosomatic disorders = medical disorders in which psychological factors play a causal role o most, if not all, medical disorders are documented as psychosomatic  Gastric ulcers = painful lesions to the lining of the stomach and duodenum, which in extreme cases can be life-threatening (one of the first medical disorders to be classified as psychosomatic). o Major cause: H. plyori infection, but itself alone is insufficient, stress also mays a major role. LO 17.17 Psychoneuroimmunology: Stress, the Immune System, and the Brain  Psychoneuroimmunology = the study of interactions among psychological factors, the nervous system, and the immune system.  The Body’s 4 Lines of Defense: 1) Behavioral immune system – humans are motivated to avoid contact with individuals who are displaying symptoms of illness; bodies are primed to respond more aggressively to infection when they perceive signs of infection in others. 2) Variety of surface barriers that keep the body from being overwhelmed i. Skin, respiratory tract, eyes ii. Includes coughing, sneezing, tears, mucous 3) Innate immune system 4) Adaptive immune system INNATE IMMUNE SYSTEM  The innate immune system = the first component of the immune system to react o Reacts quickly, generally near points of entry of pathogens to the body.  Pathogens – disease causing agents o Triggered when toll-like receptors bind to a molecules on the surface of the pathogens or when injured cells send out alarm signals or when injured cells send out alarm signals  One of the first reactions to invasion of pathogens is inflammation o Triggered by the release of chemicals from damaged cells o Ex: Cytokines – attract leukocytes and other phagocytes into the infected area.  Leukocytes = white blood cells  Phagocytes = cells that engulf and destroy pathogens o Microglia = phagocytes that are specific to the CNS o Cytokines also promote healing of the damaged tissue once the pathogens are destroyed  Phagocytosis = destruction of pathogens by phagocytes; thought to be one of the first immune reactions to have evolved.

ADAPTIVE IMMUNE SYSTEM

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Differs from the innate immune system in 4 ways o Evolved more recently, first appearing in early vertebrates o Slower; takes longer to be fully manifeszted o Specific in the sense that it reacts against specific antigens o Has memory; once it has reacted against a particular pathogen, it reacts more...