9_Emotion - Emotion Emotion: affect (bewogenheid) -depends...

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Unformatted text preview: Emotion Emotion: affect (bewogenheid) -depends on the situation -short lasting Does this charming macaque feel any emotion? Mood: (stemming) -independent of situation -longer lasting E. Munch Emotions, feelings, mood Emotions and emotions Emotions: -objective, physiologic processes (indirectly studied, e.g. by measurement of cortisol, heart rate..) -typical related to a specific situation (e.g. fear when seeing a dog) 1. Basic emotions, primary emotions (innate) Feelings: subjective (first person) have an important function in communication (through facial mimics, body language…) need some kind of consciousness. Mood: largely independent of situation longer lasting than emotions In scientific literature, the distinction between emotions and feelings is frequently overlooked. fear, rage, disgust, astonishment, joy, sorrow (angst en woede, walging en verbazing, vreugde en verdriet) primitive animals can be anxious, e.g. Aplysia no reflexes, but complex reactions 2. Cultural emotions e.g. men of the Goeroeroemba tribute in New-Guinea: “wild-men-emotion” 3. Complexe emotions social emotions, cognitive emotions, higher emotions romantic love, empathy, shame… no emotions in proper meaning In popular scientific literature, the distinction between emotions, feelings and mood is frequently overlooked. 1 Emotions and motivation Biological needs (e.g. hunger) lead (if possible) to a choise that gives satisfaction (reward as a determing effect for primary motivation) Emotions and drifts Emotions: mental processes that generate adaptive responses and conduct behavior. Basic emotions evolved because they serve as motivation (punishment and reward), enhancing fitness Nucleus accumbens, amygdala and prefrontal cortex are the basic structures of the reward system (dopaminergic) Motivation: internal and external factors that stimulate people to be interested and to exert persistent effort in attaining a goal. It results from the interactions among conscious and unconscious factors such as the (1) intensity of desire or need, (2) incentive, and (3) expectations of the individual or of others. Emotions and suppression Instinct ~ unconditional reflex ~ basic emotion automatic, unwilled, not learned behavior as reaction to specific stimuli (e.g. mother-instinct). Drifts: rests from evolution, atavisms. Can be dominated by human capacities, e.g. rationality. Robotic emotions e.g. suppressing fear: ventro-medial PFC Robot “Kismet” (MIT): can produce some emotional facial expressions Artificial life: experiments are being conducted with computers to generate emotions by theirselves Ventro-medial PFC When the ventro-medial PFC is damaged: utilitary moral judgments (e.g. to kill one person saving multiple persons) 2 Emotions and other animals Emotions and other animals Damasio (neurologist, USA) Only humans have the perception of their emotions Cognitive, polymodal neocortex is necessary Do I feel any Panksepp (biologist, USA) Other animals do have emotions The neocortex is not essential emotion? Crevits (neuropsychiatrist, Ghent) Other animals have (some) emotions, i.e. to a certain degree: gradualistic view - Subcortical structures are involved in emotions (e.g. fear) - Neocortical zones are activated during certain emotions (fMRI) e.g. feeling isolated from society Problem: how to prove ??? Theories of emotion Emotion in However, individuals with no peripheral sensation experience emotion. the brain Munch, 1893 3 Earlier views: Current view: •The hypothalamus is critical in the efferent component of emotion •The neocortex (esp. prefrontal and cingulate) is involved in the cognitive component •The amygdala (limbic system) is central to both, cortical and efferent systems Feedback from the periphery is involved in the generation of a complete emotional experience. Two pathways A direct (unconscious) path: simple, gross elements of the stimulus are analysed => direct action An indirect (conscious) path: emotional importance attached on complex information. A conscious, willed, rational correction of emotional reactions becomes possible. Parallel conscious and unconscious emotional behavior (LeDoux, 1986) Parallel conscious and unconscious emotional behavior (LeDoux, 1986) 4 Cingulate gyrus Thalamus Prefrontal cortex (control of behavior) Hypothalamus Emotional stimulus => thalamus => AMYGDALA (emotion) Hypothalamus PAG (stress system) amygdala • add the emotional colour to sensations influence behavior activate the stress systeem (if threat ) • memory for emotional events (behavior) Smell Olfactory bulb Amygdala Hippocampus Main structures: amygdala, hippocampus, gyrus cinguli, hypothalamus The limbic system is involved in emotions, memory and learning Remember the phylogeny: Fear (emotion) is an important element in case of danger, threat. The limbic system appeared early in evolution. ant cingulate cortex ant cingulate cortex brainstem nuclei orbitofrontal cortex => automatisms: registered in (genetic) memory (otherwise, every new member has to learn and to risk the same threats hypothalamus and basal forebrain Important zones for emotions Frontal: orbitofrontal cortex anterior cingulate cortex Temporal: amygdala (limbic S) hypothalamus Brainstem: some nuclei 5 Fear Science 2002, 298, 1191-4 Cortical regions implicated in emotional experience include -orbitofrontal cortex (yellow), -insular cortex ( purple), -anterior (blue) and posterior (green) cingulate cortices. The amygdala (red) is involved in linking perception with automatic emotional responses and memory. Fear Laboratory procedures for measuring fear Innate fear by a natural menace (evolutionary importance) => responses: defensive behavior, stress, autonomous reactions… Human Rodent ∆ heart rate Increase heart rate Learned fear cf. conditional reflex (Pavlov) Decreased appetite Increased startle Increased motility Decreased pain reactivity Decrease motor activity Central State of Fear Decreased appetite Increased startle Defecation Decreased pain reactivity ∆ motor activity 6 Pavlovian fear conditioning Auditory Stimulus & Shock Central State of Fear ∆ heart rate decreased salivation increased startle defecation hypoalgesia ∆ Activity Pavlovian fear conditioning Auditory Stimulus Central State of Fear ∆ heart rate decreased salivation increased startle defecation hypoalgesia ∆ Activity Pathways mediating conditioned fear If the amygdala are destroyed, a conditional reflex can no longer be elicited. PAG: periaqueductal grey 7 The amygdala modulates the storage of memory => the emotional component of memory Direct path (amygdala) => no consciousness is needed to react Indirect path (cortex) => awareness of the danger A neuropsychiatric consequence 1. Neurons learn* fear by producing proteins => pills can block these processes 2. Less connections over the cerebral cortex than over the amygdala => less rational input That is why pills help better than talking for relieving fear (Crevits, 2007) *Conditional fear; a process with ‘long term potentiation’ and production of specific proteins. Two genes: gene for Gastrin Releasing Peptide (GRP) ~ conditional fear gene for stathmine ~ conditional and innate fear Nature Reviews Neuroscience, 2001, 2, 352-63 Trends in Neuroscience, 1994, 17, 208-14 8 ...
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