Motivation - Mind, Brain and Behaviour - Lecture Slides, Slides of Human ethology

Download Motivation - Mind, Brain and Behaviour - Lecture Slides and more Slides Human ethology in PDF only on Docsity! Motivation Docsity.com Coordination of the Systems Systems are complementary. Both are active to some extent at the same time – not l ia ternat ng. What happens during anger? S h i l i bl dympat et c arousa ncreases oo pressure. Medulla detects that arousal and activates the parasympathetic to keep blood pressure within normal limits. Hypertension occurs with deficient feedback. Docsity.com Effects of Drugs Many abused drugs act directly on the modulatory systems. Hallucinogens such as LSD – agonist for serotonin, decreasing activity of raphe nuclei. Stimulants (cocaine, amphetamine) – affect DA and NE systems, causing increased alertness, self-confidence, euphoria. Mimic effects of sympathetic ANS activation . Docsity.com Drug Effects (Cont.) Stimulants block catecholamine reuptake and stimulate release of DA (dopamine), intensifying effects of DA and NE. This causes the stimulant effect. Because cocaine and amphetamine affect the reward systems, drug-seeking behaviors are reinforced leading to addiction or psychological dependence. Docsity.com What is Motivation? That which gives energy and direction to behavior. The driving force for behavior. Motivation is necessary for behavior but does not guarantee it. How we choose among competing goals is not well understood. Survival related behavior is best understood- . Docsity.com Setpoint Hypothesis of Eating Adiposity (fat storage) may be a regulator of eating behavior. Th b i di t t b li t i t i it f te ra n rec s me a o c processes o ma n a n s a store. Insulin signals the state of fat stores to the brain . Adiposity affects insulin secretion. Lean people are more sensitive to insulin so more carbohydrate is used and does not become fat. Docsity.com Appetite Control Starvation – intake of energy consistently fails to meet the body’s needs. Adiposity (fat) – intake consistently exceeds need Motivation to eat arises from a complex interplay of physiological mechanisms. Leptin levels act on the brain via peptides to inhibit or stimulate eating behavior and adjust metabolic activity. Docsity.com Short-Term Regulation Th l i d d i i i hibi de ept n-governe r ve to eat s n te by satiety signals that occur during eating. G i di i h f ll h hastr c stens on – ow u t e stomac feels – is signaled by mechanosensory receptors. Intestines release CCK in response to stimulation which inhibits appetite and, releases insulin. Insulin acts like leptin to regulate feeding . Docsity.com Dopamine Stimulates Cravings O i i ll i h h l ir g na y, eat ng was t oug t to resu t n pleasure (release of dopamine in pleasure centers of brain) . However, dopamine-depleted rats behave as if eating is pleasurable but show decreased motivation to seek food. Stimulation of dopamine pathways in hypothalamus appears to produce cravings, not pleasure . Docsity.com Serotonin Links Food to Mood Serotonin levels increase as the result of eating, resulting in mood elevation. Derived from tryptophan which comes from carbohydrates. Drugs that elevate serotonin are appetite suppressants. Abnormalities in serotonin may contribute to eating disorders accompanied by depression. Docsity.com Eating Disorders A i N d lib i dnorex a ervosa – e erate starvat on ue to psychological factors. I ffi i t b d i htnsu c en o y we g Distorted body image, food obsession Anore ics ha e normal appetitex v Bulimia Nervosa – food binging followed by purging with laxatives or vomiting . Normal body weight, typically Docsity.com Temperature Regulation Two controls: Sensors from skin Blood temperature (at hypothalamus) Heat-gain mechanisms increase blood temperature (goose bumps). Heat-loss mechanisms decrease it (shunt blood to skin, perspiration). Docsity.com Purpose of Fever Occurs when immune response causes heat- gain mechanisms to increase body temperature. Elevated temperature: Activates antibody-producing cells Increases the rate at which white blood cells move to sites of infection. Directly affect some viruses but not all. Docsity.com