Bio Neuroscience - Emotions PDF

Bio neuroscience Emotions Psychologists define emotion in terms of three component: Cognition, Action, Feeling (do not always occur together) Emotional situations arouse the autonomic nervous system(fight or flight vs rest and digest) WHILE Most situations evoke a combination of sympathetic and p...

Bio neuroscience Emotions Psychologists define emotion in terms of three component: Cognition, Action, Feeling (do not always occur together) Emotional situations arouse the autonomic nervous system(fight or flight vs rest and digest) WHILE Most situations evoke a combination of sympathetic and parasympathetic arousal. Sympathetic nervous system is what responds to stress, focusing on what the body needs to do RIGHT NOW. Basically prioritizes all energy to the brain, heart, and muscles to deal with the threat at hand. Nervous system dosent understand that some situations aren't mortal danger, and won't kill you, and physiological responses to non immediate stresses are largely the same as when you’re fighting for survival. In both sympathetic and parasympathetic divisions, almost every single needs to cross two synapses. Each neuron travels from root in spinal cord→ganglion cell→synpasing with another nerve fiber (another ganglion cell)-->leads to effector organ where it synapses to create another signal (like making your heart pump faster) STRESS RESPONSE INCLUDES TWO KINDS OF CHEMICALS: 1. Neurotransmitters 2. Hormones (products of endocrine system) Explains how our sympathetic division ultimately work A compound can be considered either a neurotransmitter or hormone. Substance released, can have different effects/opposite effects on body DEPENDING on where it is received in your body Situation of danger: Sympathetic ganglia 1. Brain sends action potentials down spinal cord and preganglionic axons, flowing all the way into ganglia. (most ganglia near spinal cord) 2. When signals reach the synapse inside ganglia, preganglionic fibers will release Ach. 3. Ach (if there is enough of it) stimulates action potentials in several neurons in postganglionic fibers. 4. Post ganglion neurons then carry A.P to effector organs 5. At the END of that same second, post ganglion cells release NOREPINEPHRINE(always norepinephrine thats released from postganglion axons in sympathetic nervous system) is what crosses final synapse and creates a response in the effector Nervous communication=acetylcholine is the currency Theories of emotions: 1. James-lange theory: emotion feelings result from bodys actions. This proposes that emotions arise as a result of autonomic arousal and skeletal actions. (brain assigns an emotion to the physical change that occurred due to stimulus) For example: "I feel afraid because my heart is racing and I am trembling." 1. Situation 2. Physical arousal 3. emotion WE OBSERVE OUR PHYSIOLOGICAL REACTION, AND THEN LABEL IT WITH AN EMOTION. Thetheory also predicts that stronger physiological responses lead to stronger emotional experiences, which is important to note. Example: Panic attacks are marked by intense sympathetic nervous system arousal (rapid heartbeat, fast breathing, etc.)-–Only if perceived as occurring spontaneously. TWO predictions: People with a weak autonomic or skeletal response should feel less emotion. Increasing one’s autonomic or skeletal response should enhance an emotion 2. Cannon bard theory: Thalamic region is the coordinating center for emotional reactions. Sends impulses to cortex and hypothalamus suggests that emotional experiences and physiological reactions occur simultaneously and independently rather than sequentially. (contrasts james-lange as there is no sequence of physical change and then emotion, they just happen at the same time). OUR HEART RACES AS WE FEEL FEAR 3. Schachter singer(two factor theory of emotions): takes the situation into context. Two components that lead to emotion arising: Physiological Arousal: The body experiences a physical reaction Cognitive Labeling/context:The brain interprets the arousal based on the situation and assigns it an emotional label (e.g., fear, excitement). So the order goes as: stimulus(seeing a snake), then cognitive label(i am afraid), then emotion(FEAR), and lastly a physiological reaction.(heart pounding) Arousal could be labeled as fear or excitement, depending on context. Research findings: paralyzed people report feeling emotion to the same degree as prior to injury. Pure autonomic failure: Output from autonomic nervous system to body fails to communicate or send. People with this condition report feeling same emotions, but less intensely. BOTOX: Botox blocks transmission at synapses and nerve muscle junction! People with botox report there are weaker than usual emotional feelings. Conclusion: Body change is important part of feeling an emotion. However, people with certain types of brain damage show normal emotional responses. Mobius synndrome Effect of certain faical expression on emotion: Creating certain body actions may also slightly influence emotion. Smiling slightly increases happiness: perception of the body's actions do contribute to emotional feelings. However, this doesn't mean that body change is required. →Möbius syndrome: People with this condition cannot move their facial muscles to smile. Area crucial for emotion: the limbic system (includes the forebrain areas surrounding thalamus) regulating emotions. HIppopotamus wearing a hat: four most important components of limbic system when it comes to emotion. Sit on top of brain stem 1. H : hypothalamus→ below thalamus. SO SMALL. Size of kidney beans. Regulates autonomic nervous system(fight or flight vs rest and digest response). It does this by controlling the endocrine system, which is the triggering of hormones to the bloodstream. Such as, norepinephrine, epinephrine/adrenaline) 2. A : amygdala → aggression center. And in charge of autonomic fear response. When stimulated you feel anger or violence, as well as fear or anxiety. If you destory amygdala/destruction (kluver bucy syndrome: less than normal fear, impaired social behaviour not knowing what to fear) it can cause a mellow effect (hyperorality:put things in mouth a lot such as eating, hypersexuality, Disinhibited behaviour which is antisocialness and impulsive and recklessness). AMYGDALA IS ALSO IN CHARGE OF enhancing STARTLE EFFECT. Which is extremely fast response to loud unexpected noises. How it works: Auditory information stimulates an area of the pons that commands tensing of neck and other muscles. The amygdala is crucial for emotional processing, particularly fear. It responds strongly to fearful stimuli and helps recognize facial expressions of fear and disgust. Damage can impair emotional arousal and recognition but does not eliminate emotion. It also regulates autonomic fear responses and behavioral reactions. What is the primary function of the amygdala in relation to emotions? A. Processing emotional stimuli, especially fear The amygdala integrates sensory and emotional information to process fear and safety. Here's how: 1. Sensory Input: The amygdala receives input from pain fibers, as well as visual and auditory signals. 2. Fear Processing: Different pathways within the amygdala are responsible for: Fear of pain. Fear of predators. Fear of aggressive members of the same species. 3. Breathing Control: One part of the amygdala regulates breathing changes in response to fear. 4. Safety Identification: Another part helps recognize and associate safe environments. 3. T : thalamus → sensory relay station (things that you see, hear, touch) thalamus directs these senses to appropriate areas of cortex. Smell bypasses thalamus and has its own private relay station (area of brain needs to be close to other areas that regulate emotions). 4. Hippo : hippocampus→curves around thalamus. Key role in forming new memories. Converts STM to LTM. When you think or reminisce, ur also evoking emotion. Damage to this area leads to difficulty in forming memories, however you would still have your old memories intact. Brain localization: Brain imaging studies show no strong evidence for specific brain areas being critical for emotions. Instead, emotional experiences activate multiple brain regions, indicating that emotions are not localized but involve broader neural networks. The limbic system is traditionally linked to emotions but is not solely responsible. Do people have a limited number of facial expressions? We rarely interpret emotion based solely on facial expressions: Two or more emotions can be present in a single facial expression. An alternative view: Emotional feelings vary along two continuous dimensions. Weak to strong, pleasant to unpleasant, approach versus avoid. Behavioural activation system: activation of left hemisphere, frontal and temporal lobe. Happiness and anger Behavioural inhibition system: increased activity of the frontal and temporal lobe of the right hemisphere (negative emotion like fear or disgust, threat or anger), increases attention and arousal, inhibits action. Functions of emotion: has adaptive value ex. fear leads to escape Aid in decision making Helps communicate needs We pay much attention to how an outcome will make us feel–Contemplating moral decisions activates the prefrontal cortex and cingulate gyrus. Damage to the prefrontal cortex blunts emotions. It impairs decision making and leads to impulsive decision making. Damage to the prefrontal medial cortex shows decreased guilt and trust, and inconsistent preferences. (nourine) We rationalize after we make a moral decision. People with high autonomic arousal would least likely sacrifice and kill one person to save 5 others. Aggressive behaviour: Aggressive behavior depends on ratio of testosterone to cortisol –Cortisol inhibits violent impulses. Aggressiveness and impulsiveness have been linked to low serotonin release, however the relation between them is small. Social isolation also lowers serotonin turnover. Genes influence violent behaviour in many ways, including autonomic arousal. (weak link). Interaction between childhood treatment and genes shows a strong link to aggression. The amount of serotonin that neurons release, absorb, and replace is Measured by the concentration of 5-HIAA in the cerebrospinal fluid. Response of the Human Amygdala to Visual Stimuli: fMRI studies show the amygdala responds strongly to photos that arouse fear or photos of faces showing fear. Response is stronger when the meaning is unclear and requires some processing. Responds more strongly to an angry face directed toward the viewer and frightened faces directed elsewhere Damage to amygdala: little arousal to unpleasant pictures, however can classify emotional PICS without difficulty. Amygdala damage affects the ability to recognize facial expressions of fear or disgust–When recognized, rated as less intense than other people Anxiety disorders; linked to hypothalamus abnormalities, decreases GABA increased orexin, more common in women. Ptsd: Smaller hippocampus may predispose people to PTSD In response to a stressful experience, the nervous system activates the immune system. PROLONGED STRESS RESPONSE WEAKENS THE IMMUNE SYSTEM –Increases production of natural killer cells, leukocytes and cytokines –The cytokines combat infections but also trigger prostaglandins Immune system: The immune system protects the body against viruses and bacteria by producing leukocytes (white blood cells)  B-cells: leukocytes that mature in the bone marrow and secrete antibodies –Antibodies: Y-shaped proteins that attach to particular kinds of antigens –Antigens: surface proteins that are antibody-generator molecules