Mechanisms of Motivation and Emotion Chapter 6

Principles of Motivation  MOTIVATION: the entire constellation of factors, some inside the organism and some outside, that cause an individual to behave in a particular way at a particular time  DRIVE: or motivational state, an internal, reversible condition in an individual that orients the individual toward one or another type of goal DRIVEINCENTIVE HUNGER

Varieties of Drives: Homeostasis HOMEOSTASIS: the constancy in the body’s internal environment that must be maintained through the expenditure of energy Regulatory drives help maintain homeostasis (hunger, thirst, sleep) Nonregulatory drives serve some other purpose

Nonregulatory Drives Fear, anger Safety Drives Mating and caring for infants Reproductive Drives Friendship and social acceptance Social Drives Play and exploration Educative Drives

Drives As States of the Brain CENTRAL-STATE THEORY OF DRIVES: theory that the most direct physiological bases for drives lie in neural activity in the brain CENTRAL DRIVE SYSTEM: a set of neurons in the brain that, when active, most directly promotes a specific drive

Three Components of Reward Medial forebrain bundle neurons whose terminals end in the nucleus accumbens release reward-related neurotransmitters. Rewards: 1.Things we like (Endorphins) 2.Things we want (Dopamine) 3.Things that serve as reinforcers (Dopamine and new learning)

Wanting and liking and an element of surprise (new learning). Dopamine Endorphin Dopamine

Three Components of Reward Medial forebrain bundle neurons whose terminals end in the nucleus accumbens release reward-related neurotransmitters. Rewards: 1.Things we like (Endorphins) 2.Things we want (Dopamine) 3.Things that serve as reinforcers (Dopamine and new learning)

Neural and Hormonal Control of Appetite  Neurons that affect appetite are located in the ARCUATE NUCLEUS  Appetite-stimulating neurons  NEUROPEPTIDE Y and appetite- suppressing neurons  peptide YY (PYY) Normal vs. Leptin mice Fat cells secrete Leptin  acts on hypothalamus to suppress appetite

Hormonal Influences on Sex Drive (all hypothalamic)  The primary hormone for male sex drive is testosterone  Testosterone has also been linked to aggression, dominance and preoccupation with social status MalesFemales  The primary female hormones for sexual drive are estrogen and progesterone

Sexual Differentiation and Determinants of Sexual Orientation  ACTIVATING EFFECTS have temporary, reversible effects  DIFFERENTIATING EFFECTS create long-lasting structural differences  Females: XX, Males: XY  “Y”  testes  male genitals/brain change  Congenital adrenal hyperplasia  Identical Twins – 50% heredity of sexual orientation  Fraternal Twins/Siblings – 15%  Male birth order - “maternal memory” for male gestations or births. (Blanchard, 2008; Bogaret, 2006).

Sleep As a Physiological and Behavioral State  SLEEP is a condition of relative unresponsiveness to the environment; influenced by a biological clock that keeps a 24 hour day- night cycle

Dreams and Other Mental Activity During Sleep TRUE DREAMS: the person feels like it is a real experience and they are sensing the situation REM SLEEP THOUGHT: tend to involve concerns that happened during the day non-REM

THE PRESERVATION AND PROTECTION THEORY Sleep came about in evolution to preserve energy and protect individuals during that portion of each 24-hour day when there is relatively little value and considerable danger in moving about E.g. herbivores sleep less than carnivores THE BODY RESTORATION THEORY  The body wears out during the day and sleep is necessary to restore it to normal functioning Large sleeping differences between animals? THE BRAIN MAINTENANCE THEORY OF REM  REM sleep provides regular exercise to groups of neurons in the brain and preserves important neural circuits (Infants vs. Adults) Mammal TrendsHours Giant Sloth20 Opossum, brown bat19 Giant Armadillo18 Owl monkey17 Arctic ground squirrel16 Tree shrew15 Cat, golden hamster14 Mouse, rat, grey wolf13 Arctic fox, chinchilla, gorilla, raccoon 12 Mountain beaver11 Rhesus monkey, chimpanzee, baboon 9 Human, rabbit, pig8 Tree hyrax, rock hyrax5 Cow, goat, elephant, donkey, sheep 3 Roe deer, horse2

Individual Variation in the Sleep Drive NONSOMNIACS need much less sleep than average and still function normally the next day INSOMNIACS have a normal sleep drive but, for whatever reason, sleep much less than they would like

Brain Mechanisms of the Daily Sleep Cycle  CIRCADIAN RHYTHM: any cyclic physiological or behavioral change in a living thing that has a period of about 1 day even in the absence of external cues signaling the time of day  Suprachiasmatic nucleus (rhythm-generating neurons)  Body temperature  Melatonin Ventromedial Preoptic Nucleus Activates sleep Lesions in this area cause permanent sleeplessness Wake-activating center in the Lateral and Posterior Hypothalamus Release OREXINS Leading cause of narcolepsy

The Nature and Value of Emotions EMOTION: a subjective feeling that is experienced as directed toward some particular object or event AFFECT: any emotional feeling MOOD: a free-floating emotional feeling, not directed at a specific object

Plutchik’s Model of Primary Emotions

Effects of Bodily Responses on Emotional Feelings  Emotions are accompanied by peripheral changes  Heart rate, blood pressure, diversion of blood, gland activation, muscle tension, facial expressions  Common sense dictates that our emotions cause these changes…but what if it’s the other way around?

Theories of Emotion  The bodily reaction to an emotion-provoking stimulus is automatic, occurring without thought or feeling at first, and the assessment of one’s emotional state comes later Emotional state depends on the sensory feedback pertaining to the body’s response as well as the person’s perceptions and thoughts about the environmental event that provoked the response

The Facial Feedback Theory of Emotion  Sensory feedback from facial expressions contributes both to emotional feelings and to the production of the full-body reactions that accompany emotions

Brain Mechanisms of Emotion  The AMYGDALA is the brain’s early warning system  Receives sensory input from:  A fast subcortical route  A slower cortical route  The PREFRONTAL CORTEX is essential for conscious experience of emotions