Chapter 17 Notes - Summary Biopsychology PDF

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1 Chapter 17 Biopsychology of Emotion, Stress, and Health 3 important qualities of fear: 1. the easiest emotion to infer from behavior in various species 2. It plays an important adaptive function in motivating the avoidance of threatening situations 3. Chronic fear is 1 common source of stress I. B...

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1 Chapter 17 – Biopsychology of Emotion, Stress, and Health 3 important qualities of fear: 1. It’s the easiest emotion to infer from behavior in various species 2. It plays an important adaptive function in motivating the avoidance of threatening situations 3. Chronic fear is 1 common source of stress I.

Biopsychology of Emotion: Introduction a. Early Landmarks in the Biopsychological Investigation of Emotion i. The Mind-Blowing Case of Phineas Gage (1848) ii. DARWIN’S THEORY OF THE EVOLUTION OF EMOTION 1. 1st major event in study of biopsychology of emotion was publication in 1872 of The Expression of Emotions in Man and Animals by Darwin a. Darwin argues largely on basis of anecdotal evidence that particular emotional responses (human facial expressions) tend to accompany same emotional states in all members of a species b. Believed that expressions of emotions are products of evolution 2. Composed of 3 main ideas: a. Expressions of emotion evolve from behaviors that indicate what animal is likely to do next b. If signals provided by such behaviors benefit the animal that displays them, they will evolve in ways that enhance their communicative function, & their original function may be lost c. Opposite messages are often signaled by opposite movements & postures, Principle of Antithesis 3. To be most effective, signals of aggression & submission must be clearly distinguishable; thus, they tend to evolve in opposite directions iii. JAMES-LANGE AND CANNON-BARD THEORIES 1. James-Lange Theory: 1884 a. Emotion-inducing sensory stimuli are received & interpreted by the cortex, which triggers changes in the visceral organs via ANS & in skeletal muscles via SNS b. Then, autonomic & somatic responses trigger experience of emotion in brain. c. Effect, James-Lange theory reversed the usual commonsense way of thinking about the causal relation b/w the experience of emotion & its expression d. Argued that autonomic activity & behavior that are triggered by emotional event (rapid heartbeat & running away) produce feeling of emotion, not vice versa 2. Cannon-Bard Theory: 1915 a. Emotional stimuli have 2 independent excitatory effects: i. Excite both feeling of emotion in brain & expression of emotion in ANS & SNS b. Views emotional experience & emotional expression as parallel processes that have no direct causal relation 3. According to James-Lange theory, emotional experience depends entirely on feedback from ANS & SNS activity 4. According to Cannon-Bard theory, emotional experience is totally independent of such feedback

2 5. Failure to unqualified support led to modern biopsychological view a. 3 principal factors in emotional response i. Perception of emotion-inducing stimulus ii. Autonomic & somatic responses to stimulus iii. Experience of emotion iv. SHAM RAGE 1. Decorticate: Lacking a cortex 2. Bard discovered decorticate cats respond aggressively to slightest provocation: After light touch, they arch their backs, erect their hair, hiss, & expose their teeth 3. Abnormal in 2 respects: a. Inappropriately severe b. Not directed at particular targets 4. Sham Rage: Exaggerated, poorly directed aggressive responses of decorticate animals 5. Can be elicited in cats whose cerebral hemispheres have been removed down to, but not including the hypothalamus, but it can’t be elicited if hypothalamus is also removed 6. Hypothalamus in critical for expression of aggressive responses & function of cortex is to inhibit & direct these responses v. LIMBIC SYSTEM AND EMOTION 1. 1937, Papez proposed that emotional expression is controlled by several interconnected nuclei & tracts that ring the thalamus 2. Limbic System: Amygdala, Mammillary Body, Hippocampus, Fornix, Cingulate Cortex, Septum, Olfactory Bulb, & Hypothalamus 3. Proposed that emotional states are expressed through action of other structures of the circuit on hypothalamus & are experienced through their action on cortex 4. Papez theory was expanded by Paul Ma& became influential limbic system theory of emotion vi. KLÜVER-BUCY SYNDROME 1. Includes following behaviors: a. Consumption of almost anything that is edible b. Increased sexual activity often directed @ inappropriate objects c. Tendency to repeatedly investigate familiar objects d. Tendency to investigate objects w/ the mouth e. Lack of fear 2. In primates, most symptoms appear to result from damage to amygdala 3. Has been observed in several species 4. A Human Case of Klüver-Bucy Syndrome b. Emotions and the Autonomic Nervous System i. Research on role of ANS in emotion has focused on 2 issues: 1. The degree to which specific patterns of ANS are associated w/ specific emotions 2. Effectiveness of ANS measures in polygraphy (lie detection) ii. EMOTIONAL SPECIFICITY OF THE AUTONOMIC NERVOUS SYSTEM 1. Experimental evidence suggests that specificity of ANS reactions lies somewhere b/w extremes of total specificity & total generality 2. Ample evidence indicates that not all emotions are associated w/ same pattern of ANS activity 3. There’s also no evidence that each emotion is characterized by distinct pattern of ANS activity iii. POLYGRAPHY

3 1. Polygraphy: Method of interrogation that employs ANS indexes of emotion to infer the truthfulness of a person’s responses 2. Main problem is evaluating the effectiveness of polygraphy is that it’s rarely possible in real-life situations to know for certain whether subject is guilty or innocent 3. Many studies have employed the Mock Crime Procedure: Volunteers participate in mock crime & are then subjected to a polygraph test by an examiner who is unaware of their “guilt” or “innocence” 4. Usual method is Control-Question Technique: The physiological response to the target question is compared w/ the physiological responses to control questions whose answers are known a. Average success rate: 80% 5. Guilty-Knowledge Technique: A.K.A. Concealed Information Test a. In order to use the polygrapher must have piece of info concerning the crime that only the guilty person knows c. Emotions and Facial Expressions i. UNIVERSALITY OF FACIAL EXPRESSION 1. Ppl of diff cultures make similar facial expressions in similar situations & can correctly identify the emotional significance of facial expressions displayed by people from cultures other than their own 2. Most convincing study was study of members of isolated New Guinea tribe ii. PRIMARY FACIAL EXPRESSIONS 1. Primary facial expressions: Surprise, anger, sadness, disgust, fear, & happiness 2. All other facial expressions of genuine emotion are composed of mixtures of the 6 primaries iii. FACIAL FEEDBACK HYPOTHESIS 1. Facial Feedback Hypothesis: Hypothesis that our facial expressions influence our emotional experience iv. VOLUNTARY CONTROL OF FACIAL EXPRESSION 1. Reasons for choosing to put on false facial expressions: a. Putting on a false smile to reassure a worried friend (+) b. Putting on a false smile to disguise a lie (-) 2. 2 ways of distinguishing true expressions from false ones a. Microexpressions (Brief facial expressions) of real emotion often break through the false one i. Last only about 0.05 sec, but w/ practice can be detected w/o aid of slow-motion photography b. There often subtle diffs b/w genuine facial expressions & false ones that can be detected by skilled observers 3. Most widely studied diff b/w genuine & false facial expression 1st described by Duchenne (French anatomist) in 1862 a. Said that simple enjoyment could be distinguished from deliberately produced smiles by consideration of 2 facial muscles that are contracted during genuine smiles: Orbicularis oculi (Encircles the eye & pulls the skin from cheeks & forehead toward eyeball) & Zygomaticus Major (Which pulls the lip corners up) b. Zygomaticus Major can be controlled voluntarily, whereas orbicularis oculi is normally contracted only by genuine pleasure 4. Duchenne Smile: Genuine smile v. FACIAL EXPRESSIONS: CURRENT PERSPECTIVES

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1. Video recordings has contributed 4 important qualifications to Ekman’s original theory: a. Now clear that Ekman’s 6 primary facial expressions of emotion rarely occur in pure form—they’re ideals w/ many subtle variations b. Existence of other primary emotions has been recognized c. Now clear that body cues, not just facial expressions, play major role in expressions of emotion d. There’s evidence that Ekman’s 6 primary facial expressions may not be universal as originally believed Fear, Defense, and Aggression a. Fear: Emotional reaction to threat; it’s motivating force for defensive behaviors b. Defensive Behaviors: Behaviors whose primary function is to protect the organism from threat or harm c. Aggressive Behaviors: Behaviors whose primary function is to threaten or ham d. Types of Aggressive and Defensive Behaviors i. Blanchard & Blanchard have derived rich descriptions of rat intraspecific aggressive & defensive behaviors by studying interactions b/w Alpha Male (Dominant male) of an established mixed-sex colony & small intruder ii. Another study by Pellis & colleagues in 1998 w/ study of cats 1. Videotaping interactions b/w cats & mice a. Diff cats react to mice in diff ways 2. Led to 2 important conclusions: a. Cats don’t play w/ their prey; cats that appeared to be playing w/ the mice were simply vacillating b/w attack & defense b. One can best understand each cat’s interactions w/ mice by locating the interactions on a linear scale (total aggressiveness at 1 end & total defensiveness at other) iii. Categories of aggressive & defensive behaviors are based on 3 criteria: 1. Their topography (form) 2. Situations that elicit them 3. Their apparent function iv. Target-Site Concept: Idea that the aggressive & defensive behaviors of an animal are often designed to attack specific sites on its own v. Rats w/ Lateral septal lesions don’t initiate more attacks, but they are hyperdefensive when threatened e. Aggression and Testosterone i. Soma & colleagues major conclusions on comparative research literature on testosterone & aggression 1. Testosterone increase social aggression in males of many species; aggression is largely abolished by castration in these same species 2. Some species, castration has no effect on social aggression; in others, castration reduces social aggression during the breeding season but not at other times 3. Relation b/w aggression & testosterone levels is difficult to interpret bc engaging in aggressive activity can itself increase testosterone levels 4. Blood level of testosterone is not the best measure. What matters more are testosterone levels in relevant areas of brain ii. Few studies have found that violent male criminals & aggressive male athletes tend to have higher testosterone levels than normal, indicating that aggressive behaviors increase testosterone Neural Mechanisms of Fear Conditioning

5 a. Fear Conditioning: The establishment of fear in response to a previously neutral stimulus (conditioned stimulus) by presenting it, usually several times, b4 delivery of an aversive stimulus (unconditioned stimulus) b. Amygdala and Fear Conditioning i. Auditory Fear Conditioning: Fear conditioning that used a sound as a conditional stimulus ii. LeDoux & colleagues began search for the neural mechanism of auditory fear conditioning by making lesions in auditory pathways of rats 1. Found that bilateral lesions to medial geniculate nucleus blocked for fear conditioning to a tone 2. But bilateral lesions to auditory cortex didn’t 3. Indicates that in order for auditory fear conditioning to occur, it’s necessary for signals elicited by tone to reach the medial geniculate nucleus but not the auditory cortex a. Also indicates that pathway from medial geniculate nucleus to structure other than auditory cortex (amygdala) plays key role in fear conditioning iii. Medial Geniculate Nucleus (MGN): Auditory relay nucleus of the thalamus iv. Pathway to PAG elicits appropriate defensive responses v. Pathway to lateral hypothalamus elicits appropriate sympathetic vi. 2 pathways to from MGN to amygdala: 1. Direct one 2. Indirect one: Projects via auditory cortex 3. Only cortical route is capable of mediating fear conditioning to complex sounds vii. Sound signals from MGN of thalamus reach the amygdala directly, or indirectly via auditory cortex c. Contextual Fear Conditioning and the Hippocampus i. Contextual Fear Conditioning: Process by which benign contexts come to elicit fear through their association w/ fear-inducing stimuli ii. Has been produced in lab in 2 ways: 1. Been produced by conventional fear-conditioning procedure a. Ex. If rat repeatedly receives an electric shock following conditional stimulus, such as tone, the rat will become fearful of the conditional context (test chamber) and the tone 2. Been produced by delivering aversive stimuli in a particular context in the absence of any other conditional stimulus a. Ex. If rat receives shocks in a distinctive test chamber, the rat will become fearful of that chamber 3. Bilateral hippocampus lesions block the subsequent development of fear response to context w/o blocking the development of a fear response to the explicit conditional stimulus d. Amygdala Complex and Fear Conditioning i. Amygdala Complex: Cluster of many nuclei ii. Lateral Nucleus of the Amygdala: Critically involved in acquisition, storage, & expression of conditioned fear iii. Prefrontal cortex: Thought to act on lateral nucleus of amygdala to suppress conditioned fear iv. Hippocampus: Thought to interact w/ that part of amygdala to mediate learning about the context of fear-related events v. Amygdala: Thought to control defensive behavior via outputs from central nucleus of amygdala

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Brain Mechanisms of Human Emotion a. Cognitive Neuroscience of Emotion i. Studies using fMRI to see people experiencing or imaging emotions or watching others experience emotions have established 3 points that have advanced our understanding of brain mechanisms of emotions in fundamental ways 1. Brain activity associated w/ each human emotion is diffuse—there isn’t a center for each emotion a. “Mosaic” for locations of brain mechanisms of emotion 2. There’s virtually always activity in motor & sensory cortices when person experiences an emotion or empathizes w/ person experiencing an emotion 3. Similar patterns of brain activity tend to be recorded when person experiences an emotion, imagines that emotion, or sees somebody else experience that emotion ii. 3 fundamental findings are influencing how researchers are thinking about the neural mechanisms of emotion iii. Embodiment of Emotions: Re-experiencing of relate patterns of motor, autonomic, & sensory neural activity during emotional experiences iv. Findings may help explain the remarkable ability of humans to empathize w/ others b. Amygdala and Human Emotion i. Amygdalae appear to play a role in performance of any task w/ an emotional component 1. Play role in evaluating emotional significance of situations ii. The Case of S.P., the Woman Who Couldn’t Perceive Fear iii. Urbach-Wiethe Disease: Genetic disorder that often results in calcification of the amygdala & surrounding anterior medial temporal-lobe structures in both hemispheres 1. 1 patient w/ bilateral amygdalar damage was found to have lost ability to recognize facial expressions of fear 2. Patients sometimes have difficulty recognizing other complex visual stimuli iv. Calcification: Hardening by conversion to calcium carbonate, the main component of bone c. Medial Prefrontal Lobes and Human Emotion i. Emotion & cognition often studied independently, but it’s believed that they’re better studied as diff components of same system ii. Functional brain-imaging studies have found evidence of activity in medial prefrontal lobes when emotional reactions are being cognitively suppressed or re-evaluated iii. Suppression Paradigms: Participants are directed to inhibit their emotional reactions to unpleasant films or pictures iv. Reappraisal Paradigms: Participants are instructed to reinterpret a picture to change their emotional reaction to it v. When both paradigms used the medial prefrontal lobes are active & seem to exert their cognitive control of emotion by interacting w/ amygdala vi. Theories of medial prefrontal lobes function: 1. Monitor diff b/w outcome & expectancy 2. Encode stimulus value over time 3. Predict likelihood of error 4. Mediate the conscious awareness of emotional stimuli 5. Medial social decision making vii. Kawasaki & colleagues used microelectrodes to record from 267 neurons in anterior cingulate cortices of 4 patients prior to surgery 1. Assessed activity of neurons when patients viewed photographs w/ emotional content

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2. Of 267 neurons, 56 responses most strongly & consistently to negative emotional content 3. Confirms previous research linking medial prefrontal w/ negative emotional reactions 4. Also shows that not all neurons in area perform same function a. Neurons directly involved in emotional processing appear to be sparse & widely distributed in human medial prefrontal lobes d. Lateralization of Emotion i. Evidence suggesting that emotional functions are lateralized, left & right cerebral hemispheres are specialized to perform diff emotional functions ii. Theories of cerebral lateralization of emotion: 1. Right Hemisphere Model: Holds that right hemisphere is specialized for all aspects of emotional processing: perception, expression, & experience of emotion 2. Valence Model: Proposes that the right hemisphere is specialized for processing negative emotion & the left hemisphere is specialized for processing positive emotion iii. Wager & colleagues conclusion was that current theories of lateralization of emotion are too general from neuroanatomical perspective iv. Overall comparisons revealed no interhemispheric diff in amount of emotional processing or valence of emotions being processed v. However, when comparisons were conducted on structure-by-structure bases, they revealed substantial evidence of lateralization of emotional processing 1. More activity is observed in left amygdala vi. Another approach, based on observing the asymmetry of facial expressions e. Neural Mechanisms of Human Emotion: Current Perspectives i. 4 important points: 1. Emotional situations produce widespread increases in cerebral activity, not just in the amygdalae & prefrontal cortex 2. All brain areas activated by emotional stimuli are also activated during other psychological processes 3. No brain structure has been invariably linked to a particular emotion 4. The same emotional stimuli often activate diff areas in diff people Stress and Health a. Stressors: Experiences that induce the stress response b. The Stress Response i. Hans Selye, 1st described stress response in 1950s & emphasized its dual nature ii. Short term, produces adaptive changes that help the animal respond to stressor 1. Ex: Mobilization of energy resources iii. Long term, produces changes that area maladaptive 1. Ex: Enlarged adrenal glands iv. Attributed the stress response to activation of anterior-pituitary adrenal-cortex system v. Concluded that stressors acting on neural circuits stimulate the release of adrenocorticotropic hormone (ACTH) 1. ACTH triggers release of glucocorticoids from adrenal cortex & glucocorticoids produce many of components of stress response vi. Stressors activate the SNS, increasing the amounts of epinephrine & norepinephrine released from adrenal medulla vii. In 1990s it was discovered that stressors produce physiological reactions that participate in the body’s inflammatory responses

8 viii. Cytokines: Group of peptide hormones that are released by many cells & participate in a variety of physiological & immunological responses, causing inflammation & fever ix. Stressors produce an increase in blood levels of cytokines c. Animal Models of Stress i. 2 problems w/ extreme forms of stress research: 1. Ethics 2. Are often of questionable scientific value ii. Better animal models of stress involve the study of social threat from conspecifics iii. Subordination Stress: When conspecific threat becomes an enduring feature of daily life 1. Most readily studied in social species that form dominance hierarchies d. Psychosomatic Disorders: The Case of Gastric Ulcers i. Psych...