Motivation and Emotion - NS101-11_Eng PDF

Motivation and Emotions Lect. Univ. Dr. Claudiu Papasteri Chapter 1: Applying Research to [email protected] Everyday Exercise and Sport Introduction Affective neuroscience Emotional experience (feelings), emotional expression Behaviors presumed the expressions of...

Motivation and Emotions Lect. Univ. Dr. Claudiu Papasteri Chapter 1: Applying Research to [email protected] Everyday Exercise and Sport Introduction Affective neuroscience Emotional experience (feelings), emotional expression Behaviors presumed the expressions of internal emotions. Brain mechanisms of emotion derived from: – Animal models -> interpreted in the context of emotions, can’t determine feelings – Human studies – Brain lesions No one emotion system like sensory systems Early Theories of Emotion Darwin made the important observations that people in different cultures experience the same emotions and that animals appear to express some of the same emotions as humans. Expressions of anger in animals and humans. These drawings are from Darwin’s book The Expression of the Emotions in Man and Animals; they were used to support his claim that there are basic universal emotions. Darwin conducted one of the first extensive studies of emotional expression. Source: John van Wyhe, ed. 2002. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/) Early Theories of Emotion (cont.) The James–Lange theory: emotion experienced in response to physiological changes in body The Cannon–Bard theory: emotions occur independent of emotional expression—no correlation with physiological state – transection of the spinal cord => eliminates body sensations, doesn’t abolish emotion – stimulus–response neural loop: cerebral cortex – emotion: thalamus A comparison of the James–Lange and Cannon– Bard theories of emotion. In the James–Lange theory (red arrows), the man perceives the threatening animal and reacts. When he senses his body’s response to the situation, he becomes afraid. In the Cannon–Bard theory (blue arrows), the threatening stimulus first causes the feeling of fear, and the man’s reaction follows. Implications of Unconscious Emotion Interoceptive awareness = aware of our body’s autonomic function Stimulus can have emotional impact without conscious awareness. – Aversive conditioning to masked stimulus results in: Increased skin conductance (autonomic arousal) Increased activity in the amygdala Many possible ways for the brain to process emotional information Different emotions may depend on different neural circuits  Unconscious Emotional Brain Activity Unconscious emotional brain activity. (a) Human subjects were conditioned using photos of expressionless and angry faces. Subjects responded to the angry face, paired with a loud unpleasant sound, with increased ANS activity (skin conductance). (b) In the testing phase, an angry face was shown briefly, followed immediately by an expressionless face. Subjects reported seeing only the expressionless face, but increased skin conductance still occurred. (c) Despite the fact that the angry face was not perceived in the testing phase, amygdala activation (red and yellow) occurred only when an angry face preceded the masking stimulus. (Source: Morris, Öhman, and Dolan, 1998.)  The Limbic System Broca’s limbic lobe (1878) – Areas of brain forming a ring around corpus callosum (“libus” lat. border): cingulate gyrus, medial surface of temporal lobe, hippocampus System for emotion? Broca didn’t propose this The limbic lobe. Broca defined the limbic lobe as the structures that form a ring around the brain stem and corpus callosum on the medial walls of the brain. The main structures in the limbic lobe labeled here are the cingulate gyrus, medial temporal cortex, and the hippocampus. The brain stem has been removed in the illustration to make the medial surface of the temporal lobe visible.  The Papez Circuit James Papez (1930): emotional system on the medial wall of the brain linking cortex with hypothalamus – cortex-hypothalamus communication is mediated and is bidirectional => consistent with both the James–Lange and the Cannon–Bard theories of emotion The Papez circuit. Papez believed that the experience of emotion was determined by activity in the cingulate cortex and, less directly, other cortical areas. Emotional expression was thought to be governed by the hypothalamus. The cingulate cortex projects to the hippocampus, and the hippocampus projects to the hypothalamus by way of the bundle of axons called the fornix. Hypothalamic effects reach the cortex via a relay in the anterior thalamic nuclei. The Papez Circuit—(cont.) Cortex critical for emotional experience Hippocampus governs behavioral expression of emotion – Rabies infection implicates hippocampus in emotion -> hyperemotional responses Anterior thalamus – Lesions lead to spontaneous laughing or crying Paul MacLean popularized the term limbic system – Evolution of limbic system allows animals to experience and express emotions beyond stereotyped brain stem behaviors. The Limbic System—(cont.) Difficulties with the single emotion system concept – Diversity of emotions and brain activity – Many structures involved in emotion No one-to-one relationship between structure and function – Limbic system: use of single, discrete emotion system questionable Emotion Theories and Neural Representations Early theories of emotion and limbic system built on introspection and inference from brain injury and disease. Studies of disease and consequences of lesions not ideal for revealing normal function. More recent theories of emotion – Basic emotion theories – Dimension emotion theories Basic Emotion Theories Certain emotions thought to be unique, indivisible, universal experiences – Anger, disgust, fear, happiness, sadness, surprise Hypothesis that basic emotions have distinct representations or circuits in brain – Analogous to distinct representations for sensory experiences E.g. emotion correlates with activity in regions: sadness - medial prefrontal cortex fear - amygdala fMRI: different activation “hotspots” associated with the basic emotions – Patterns of activity, not single areas, may represent emotions Basic Emotion Theories - (cont.) Brain activation associated with five basic emotions. For each emotion, the strength of brain activation is indicated by color (yellow greater than red). The lower brain image compares activations associated with sadness (red and yellow greater sadness activity) and fear (blue greater fear activity). (Source: Hamann, 2012, p. 460.) Dimension Emotion Theories Emotions can be broken down into smaller fundamental elements. – Combined in different ways and differing amounts – Emotions correspond to brain activation along dimensions such as valence and arousal Valence (“pleasant–unpleasant”) Arousal (“weak emotion–strong emotion”) Psychological constructionist theories of emotion – Variation on dimensional theories dimensions do not carry affective weight, they are physiological processes that, on their own, do not concern only emotion – Includes nonemotional psychological components: language, attention, internal sensations from the body, and external sensations from the environment – Emotion an emergent consequence of combined components A Dimensional Representation of Basic Emotions A dimensional representation of basic emotions. In a dimensional theory, emotions such as happiness and sadness consist of differing amounts of brain activation corresponding to affective dimensions such as valence and arousal. (Source: Hamann, 2012, p. 461.) What Is an Emotion? Great diversity of perspectives on nature of emotions Unknown whether each emotion is represented by: – Activity in a specialized area of the brain – A network of areas – A more diffuse network of neurons Study approaches – Behavioral observations – Physiological recordings – Studies of effects of lesions and disease Fear and the Amygdala Research on fear and anger provides good examples of study of emotion The amygdala seems critical for emotion of fear – Other brain structures also involved – Amygdala active also in other emotional states Much research has been done on the amygdala The Amygdaloids - Anxious (album) 1. Anxious - 0:00 2. Once Bitten, Twice Shy - 3:16 3. Harm's Way - 5:43 4. Mind of Your Own - 7:37 5. Maybe I Lost My Mind - 10:51 6. What It Is to Be - 13:25 Book: Anxious (LeDoux, 2015) The Klüver–Bucy Syndrome Produced by temporal lobectomy (removal of the temporal lobes) in rhesus monkeys – Decreased fear and aggression – Decreased vocalizations and facial expressions of fear – Visual recognition problems, oral tendencies, and hypersexuality Temporal lobe lesions in humans—particularly lesions in amygdala – Exhibit symptoms of Klüver–Bucy syndrome – Flattened emotions – Same symptoms as monkeys: visual recognition problems, oral tendencies, and hypersexuality  Anatomy of the Amygdala below the cortex on the medial side gr. “almond” = complex of nuclei: 1. basolateral nuclei, 2. corticomedial nuclei, 3. central nucleus. A cross section of the amygdala. (a) Lateral and medial views of the temporal lobe, showing the location of the amygdala in relation to the hippocampus. (b) The brain is sectioned coronally to show the amygdala in cross section. The basolateral nuclei (surrounded by red) receive visual, auditory, gustatory, and tactile afferents. The corticomedial nuclei (surrounded by purple) receive olfactory afferents. Effects of Amygdala Stimulation and Lesions Bilateral amygdalectomy reduces fear and aggression in all tested animals – Anger, sadness, and disgust may also be affected S.M. case study of bilateral destruction of the amygdala: – inability to recognize fear in facial expressions not looking at the eyes of people fear is normally recognized by a two-way interaction between the amygdala and the visual cortex: amygdala instructs the visual system to move the eyes to determine the emotional expression – could recognize fear from tone of voice Electrical stimulation of amygdala -> increased vigilance or attention—anxiety and fear in humans fMRI imaging: Fearful faces evoke greater amygdala activity than happy or neutral faces. fMRI: Amygdala role in fear Key role in detecting fearful and threatening stimuli Some studies have reported amygdala activation in response to other facial expressions including happiness, sadness, and anger Human brain activity in response to emotional stimuli. (a) Neutral and fearful faces were used as visual stimuli. (b) Fearful faces produced greater activity in the amygdala (red and yellow areas within white squares) than neutral faces. (c) No difference in amygdala activity occurred in response to happy and neutral faces. (Source: Breiter et al., 1996.)  Neural Circuit for Learned Fear Emotional events are particularly vivid and long-lasting, especially fear (e.g. PTSD) Amygdala involved in forming memories of emotional and painful events -> Joseph LeDoux: removing amygdala eliminates the visceral conditioned fear response Confirmed on humans by – fMRI imaging – PET imaging A neural circuit for learned fear. Through conditioning, a sound tone becomes associated with the pain of an electrical shock. The fear response is mediated by the amygdala. The benign tone and the painful shock reach the basolateral nuclei of the amygdala by way of auditory and somatosensory cortex, and the signal is relayed to the central nucleus. The pairing of these stimuli leads to synaptic change in the amygdala and an enhanced response to the benign tone. Efferents from the amygdala project to the brain stem periaqueductal gray matter, causing the behavioral reaction to the conditioned tone, and to the hypothalamus, resulting in the autonomic response. The experience of an unpleasant emotion presumably involves projections to the cerebral cortex. Anger and Aggression—Intertwined in Animals Anger and Aggression: separate (aggression is not an emotion), but intertwined in animals because we cannot ask about emotion Predatory aggression—attack – Against different species for food – Few vocalizations, attack head or neck – No activity in sympathetic division of ANS Affective aggression—for show – Used for show, not kill for food – High levels of sympathetic activity – Makes vocalizations, threatening posture Amygdala lesions in animals -> less aggression, low in dominance hierarchy The Amygdala and Aggression Surgery to reduce human aggression – Amygdalectomy electrodes are passed into the temporal lobe with tip in amygdala electrical current passed through the electrode / injected solution => destroy amygdala – Psychosurgery—now treatment of last resort Results Reduced aggressive behavior Relief from anxiety Profound, unpleasant side effects Transorbital lobotomy. 1949 Nobel Prize in Medicine won by Egas Moniz for development of the frontal lobotomy technique Neural Components of Anger and Aggression Beyond the Amygdala The hypothalamus and aggression – Removal of cerebral hemispheres (telencephalon) but not hypothalamus -> sham rage sham rage = manifestations of rage without attack in situations that normally would not cause anger – Behavior reversed with additional lesions in hypothalamus Brain transections and sham rage. ➀ If the cerebral hemispheres are removed and the hypothalamus Hypothalamus may is left intact, sham rage results. normally be inhibited by ➀ and ➁ A similar result is obtained if the anterior hypothalamus is removed in addition to the cerebral cortex. telencephalon ➀, ➁, and ➂ If the posterior hypothalamus is removed in addition to the anterior hypothalamus, sham rage does not result. The Hypothalamus and Aggression John Flynn’s research – Elicited affective aggression (threat attack, similar to rage response) by stimulating medial hypothalamus – Predatory aggression (silent-biting attack) elicited by stimulating lateral hypothalamus not accompanied by the dramatic threatening gestures of affective aggression; crude attack Rage reactions in cats with hypothalamic stimulation. (a) Stimulation of the medial hypothalamus produces affective aggression (threat attack). (b) Stimulation of the lateral hypothalamus evokes predatory aggression (silent-biting attack). (Source: Flynn, 1967, p. 45.) The Midbrain and Aggression Two hypothalamic pathways to brain stem involving autonomic function – Medial forebrain bundle includes axons from the lateral hypothalamus projects to -> ventral tegmental area (VTA) => predatory aggression Lesions and stimulation of VTA affects behavior; hypothalamic stimulation does not -> may have only mediated effect, may also not be required – Dorsal longitudinal fasciculus projects to -> periaqueductal gray matter (PAG) => affective aggression Lesions and stimulation of PAG affects behavior; appears to influence behavior based on based on input from the amygdala A Neural Circuit for Anger and Aggression A neural circuit for anger and aggression. (a) The hypothalamus can influence aggressive behavior through projections to the ventral tegmental area and the periaqueductal gray matter. (b) In this simplified scheme, the expression of anger and aggression is controlled by a neural pathway from the amygdala through the hypothalamus, periaqueductal gray matter (PAG), and ventral tegmental area. Serotonergic Regulation of Anger and Aggression Serotonin deficiency hypothesis – Aggression is inversely related to serotonergic activity Serotonergic raphe neurons project to the hypothalamus and limbic structures via the medial forebrain bundle – Serotonin turnover—aggression in rodents turnover rate = rate of synthesis, release, and resynthesis of neurotransmitter Drug PCPA blocks serotonin synthesis—aggression – 2 out of 14 serotonin receptor subtypes involved in modulating anger and aggression — more aggressive or more impulsive? – Negative feedback loop: Some serotonin receptors are autoreceptors and are presynaptic on the raphe neurons which activated inhibit further serotonin release In humans also, reports of negative correlation between serotonin activity and aggression  Special Interest Phineas Gage – Dr. John Harlow articles: – 1848 “Passage of an Iron Rod Through the Head.” – 1868 “Recovery from the Passage of an Iron Bar Through the The path of the iron rod through Head” Gage’s skull. (Source: Damasio et al., 1994, p. 1104.) – hole through his head was more than 9 cm in diameter; projectile destroyed a considerable portion of the skull and left frontal lobe – Before: He possessed a well-balanced mind, and was looked upon by those who knew him as a shrewd, smart business man, very persistent in executing all his plans of operation” (pp. 339–340). – After: The equilibrium or balance, so to speak, between his intellectual faculties and animal propensities, seems to have been destroyed. He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint […]. His mind was radically changed, so decidedly that his friends and acquaintances said he was “no longer Gage.” (pp. 339–340) Phineas Gage and the rod that passed through his brain. (Source: Wikimedia.) Concepts Antonio Damasio – Emotions = programs of actions that rapidly modify the state of several components of our bodies in response, for instance, to a threat or an opportunity – Feelings are the mental experiences of body states, including those that are caused by emotions -> feeling of a specific affective state hub spoke Neural architecture terminology hub = convergence–divergence zone Concluding Remarks Controversy remains about extent to which emotions cause body changes or bodily changes cause emotions. Brain imaging shows emotions are associated with widespread brain activation. Some brain structures activated in multiple emotional states, others more specific to particular emotions. Emotional experiences are the result of complex interactions among sensory stimuli, brain circuitry, past experiences, and activity of neurotransmitter systems.