Emotion Lecture Notes PDF

Emotion Dr Allison Matthews Lecture Outline Introduction to Emotion and the Brain Defining Emotion Early Hallmarks The neurobiology of Emotion The Amygdala and Fear Conditioning Animal Models Neuropsychology Human Models (implicit and Explicit Learning) Emo...

Emotion Dr Allison Matthews Lecture Outline Introduction to Emotion and the Brain Defining Emotion Early Hallmarks The neurobiology of Emotion The Amygdala and Fear Conditioning Animal Models Neuropsychology Human Models (implicit and Explicit Learning) Emotion and Cognition Attention Decision making Cognitive Control Stress and Health Stress response Psychosomatic disorders Psychoneuroimmunology  What are Emotions? Valenced responses to external stimuli and/or internal representations that…. Involve changes in multiple systems (experiential, behavioural, physiological) Are distinct from moods Can be unlearned or learned responses Involves appraisal of stimuli in terms of current goals Depend on different neural systems This Photo by Unknown Author is licensed under CC BY What are Emotions? Three components of emotion 1. a physiological reaction 2. a behavioural response 3. a feeling This Photo by Unknown Author is licensed under CC BY Defining emotion Basic emotions (Ekman): innate, universal, short-lasting Complex emotions (e.g., jealousy, parental love, romantic love) – longer lasting, no universal facial expression, socially/culturally learned Defining emotion Dimensions of emotion Valence (positive, negative) Arousal (intensity of response) Approach/withdraw Early Landmarks: The mind blowing case of Phineas Gage Phineus Gage (1848) - Iron bar through the skull resulted in dramatic changes in personality Computerised reconstruction shows damage to the medial prefrontal lobes (Damasio et al 1994) Early Landmarks: Darwin’s Theory of the Evolution of Emotional Expression (1872) Expressions of emotion evolved from behaviours indicating what an animal is likely to do next. Beneficial emotional signals will evolve to enhance communicative function. “principle of antithesis” Early Landmarks: Theories of Emotion James-Lange (1884) Stimulus triggers autonomic/skeletal response which triggers emotion Cannon-Bard (1915+) Stimulus triggers autonomic/skeletal response (emotional expression) and emotion in parallel  Theories of Emotion James-Lange Cannon-Bard Appraisal theory perception>cognitive appraisal >emotion>response Singer-Schacter Theory perception>general physiological reaction >cognition>emotion  Early Landmarks: Sham Rage Bard (1929) - decorticated cats exhibit extreme and unfocused aggressive responses Hypothalamus must be intact for sham rage to occur Hypothalamus is needed for expression of aggression and cortex serves to inhibit and direct responses? Early Landmarks: Limbic System and Emotion Papez (1937) proposed emotional circuit (limbic system) that includes hypothalamus Early Landmarks: Kluver-Bucy Syndrome (~1939) Kluver-Bucy syndrome Rare neurological disorder - bilateral damage to amygdala Major symptoms - lack of fear, urge to put objects into mouth, memory loss, hyper sexuality, visual distractibility, placidity, emotional blunting  Brain areas involved in Emotional Processing Amygdala Thalamus Hypothalamus (physiological & hormonal responses) Prefrontal cortex Orbito-frontal ACC Ventral striatum Insula Brain areas involved in Emotional Processing (physiological responses) Autonomic NS and HPA axis Brain areas involved in Emotional Processing Emotional processing involves the interaction between diverse regions of the brain  Brain areas involved in Emotional Processing Three main points have advanced the understanding of brain mechanisms of emotion Brain activity associated with each human emotion is diffuse There is usually motor and sensory regional activity along with an emotional response Brain activity for experienced, imagined, or observed emotion is similar The Amygdala Fear Conditioning Paradigm https://www.youtube.com/watch?v=ZlZekx1P1g4  The Amygdala and Fear Conditioning Lesions to amygdala blocks fear conditioning (but not UCR to aversive stimulus)  Sensory and thalamic inputs related to the CS and US converge on the lateral nucleus and induce synaptic plasticity  The Amygdala and Fear Conditioning Low road (be fast) Fast subcortical pathway via thalamus Rapid detection of threat High road (be sure) Slower cortical pathway Complex analysis of stimuli Contextual Fear Conditioning and the Hippocampus Pair an aversive stimulus with the context instead of with a discrete stimulus Bilateral hippocampal lesions Before training – prevents contextual conditioning Shortly after training – blocks retention of contextual fear conditioning  The Amygdala and Fear Conditioning: Summary The lateral nucleus of the amygdala is most critical in conditioned fear Conditioned fear is suppressed by the prefrontal cortex inhibiting the lateral amygdala The hippocampus mediates conditioned fear learning by informing the lateral amygdala about the context of the fear- related event Outputs from central nucleus regulate defensive behaviour and physiological responses  The Amygdala: Case study (SM) Urbach-Wiethe disease Specific deficit in identifying / reproducing fearful emotional expressions Not a conceptual deficit  Implicit Emotional Learning in Humans: Case study SP Lateral amygdala damage due to lobectomy to relieve epilepsy Unable to recognise fearful facial expressions (like SM) Did not acquire CR in fear conditioning paradigm  Skin Conductance Response (SCR) Emotional stimuli/situations initiate bodily responses (e.g. , sweating) which can be measured using a skin conductance response (SCR) Implicit Emotional Learning in Humans: Case study SP Explicit Emotional Learning Interactions between the hippocampus and amygdala 1. Normal indirect emotional responses to stimuli that are learned explicitly (instruction, observation, experience) 2. Enhancement of strength of explicit memories for emotional events  Indirect Emotional Responses to Explicit Learning Instructed fear paradigm Amygdala also plays a role in indirect expression of fear response Enhancement of Emotional Explicit Memories Arousal-induced enhancement of maze learning is blocked by lesions to the amygdala Arousal-induced enhancement can occur after initial encoding (ie during retention interval) Enhancement of Emotional Explicit Memories Mild arousal enhances explicit memory for emotional events (blocked by amygdala damage) Activity in amygdala is correlated with arousal- enhanced recollection Increased connectivity between amygdala and hippocampus during recall of emotional memories Flashbulb memories The Influence of Emotion on Perception and Attention Amygdala plays role in enhancing attention to emotional stimuli by enhancing early sensory processing via feedback projections to sensory cortex Attentional blink is reduced when the second of two words is emotional Early sensory areas are activated by phobic stimuli The Influence of Emotion on Perception and Attention High spider fear is associated with threat-specific attentional hypervigilance, as indexed by enhanced P1 amplitude at occipital electrode sites (Venetacci, Johnstone, Kirkby, & Matthews, 2018).  The Influence of Emotion on Decision Making Decision making is influenced by emotions – mediated by OFC OFC damage affects ability to respond to changing patterns of reward (medial) / punishment (lateral) in Iowa gambling task The Influence of Emotion on Decision Making Damasio et al – Somatic marker hypothesis Changes in physiological arousal to emotional events (e.g. a risky situation) are stored as "somatic markers" in memory Retrieval (or similar situations) reinstates the somatic markers and guides behaviour (e.g. making a response more or less likely) The Influence of Emotion on Decision Making Activation of medial OFC associated with experience and anticipation of regret Ppl with OFC damage don’t feel regret or anticipate negative consequences Cognitive Control of Emotion Process model of emotion regulation (Gross, 1998, 2015; Ochsner et al., 2012) Cognitive Control of Emotion Effects of cognitive control on emotional responses Gross (1998) - participants watched disgust eliciting film under 3 conditions (reappraisal, suppression, control) Measured subjective disgust, physiological reactions Only reappraisal reduced experience of disgust Suppression increased and prolonged sympathetic activation  Effects of cognitive control on brain activity Ochsner et al (2002) Reappraisal of negative emotions increased PFC activity, decreased amygdala activity PFC can modulate emotion generation in subcortical areas Ochsner, K. N., Bunge, S. A., Gross, J. J., & Gabrieli, J. D. (2002). Rethinking feelings: an FMRI study of the cognitive regulation of emotion. Journal of cognitive neuroscience, 14(8), 1215-1229. Effects of cognitive control on brain activity Ochsner et al (2004) Up or down regulate emotions to negative images Left lPFC, dACC activated by increasing or decreasing emotion Modulation of amygdala activation Ochsner, K. N., Ray, R. D., Cooper, J. C., Robertson, E. R., Chopra, S., Gabrieli, J. D., & Gross, J. J. (2004). For better or for worse: neural systems supporting the cognitive down-and up-regulation of negative emotion. Neuroimage, 23(2), 483-499. Effects of cognitive control on brain activity: Summary Ochsner et al 2012 Emotion regulation is controlled by areas of the prefrontal and cingulate cortex Often accompanied by decreased activation of emotion generation areas such as the amygdala and ventral striatum Ochsner et al. (2012)  Stress and Health Stress (stress response) – reaction to harm or threat (Selye, 1950s) Stressors – stimuli that cause stress Chronic psychological stress – most clearly linked to ill health In the short-term, stress is adaptive In the long-term, stress is maladaptive The Stress Response: Stress hormones Activation of the HPA axis resulting in release of hormones Activation of the sympathetic NS Brief stressors - release of cytokines (involved in inflammation and fever)  The Stress Response Stress responses are complex and varied Type of stressor, timing of stressor Individual differences, such as attitude, affect the magnitude of the stress response Example: women awaiting surgery who were “certain” they did not have breast cancer had milder stress than others Animal Models Some early models used levels of stress that might not have a human equivalent Some more recent models use social stresses (threat from conspecifics) Subordination stress in dominance hierarchies such as rats Subordinate male rats are more likely to attack juveniles, have smaller testes, lower blood testosterone and higher levels of glucocorticoids Psychosomatic Disorders: The Case of Gastric Ulcers Psychosomatic disorders – medical disorders with psychological causes For example: Gastric ulcers – lesions of stomach lining and duodenum More common in those who are stressed Ulcers are caused by a bacteria – stress appears to makes the body vulnerable to this bacteria  Psychoneuroimmunology Study of the interaction of psychological factors, the nervous system, and the immune system Immune system: protects us from infectious diseases by detecting and identifying antigens on cell surfaces Pathogens: disease causing agents Divisions of the mammalian immune system Innate immune system Attacks generic classes of pathogens Phagocytes destroy and consume pathogens and release cytokines (triggering inflammatory response) Adaptive immune system Targets specific pathogens identified by their antigens (basis of vaccination) Cytokines activate lymphocytes (white blood cells) Cell-mediated (T lymphocytes) Antibody-mediated (B lymphocytes) What Effect Does Stress Have on Immune Function: Disruptive or Beneficial? Effects of stress on immune function depends on the kind of stress Acute stressors improve (innate) immune function Chronic stressors impair (adaptive) immune function Evidence for a strong link between stress and susceptibility to infectious disease but sometimes difficult to establish causality  Early Experience of Stress Stress or mistreatment early in life may cause brain & endocrine abnormalities later Increase risk of psychiatric disorders among susceptible individuals Increase intensity of stress response (release of glucocorticoids) Handled rat pups show more adaptive stress response in adulthood (less glucocorticoids following stress) Due to handling or more grooming/licking by mothers?  Stress and the Hippocampus Hippocampus has many glucocorticoid receptors & is particularly susceptible to stress Following stress Dendrites of pyramidal cells are shorter and less branched Adult neurogenesis of granule cells reduced Disruption on hippocampus dependent tasks Effects blocked with adrenalectomy; produced with corticosteroids