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  • 1. What Causes Emotional and Motivated Behavior? An Introduction to Brain and Behavior Third Edition CHAPTER 12 PowerPoints prepared by: Paul Smaldino, UC Davis, Department of Psychology Bryan Kolb & Ian Q. Whishaw
  • 2. What Causes Emotional and Motivated Behavior?
    • Identifying the Causes of Behavior
    • Biology, Evolution, and Environment
    • Neuroanatomy of Motivated Behavior
    • Stimulating Emotion
    • Control of Regulatory Behavior
    • Control of Nonregulatory Behavior
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 3. Identifying the Causes of Behavior
    • Emotion
      • Cognitive interpretation of subjective feelings
    • Motivation
      • Behavior that seems purposeful and goal directed
    • Neuroanatomy of Emotion and Motivation
      • Hypothalamus
      • Limbic System
      • Frontal Lobes
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 4. Identifying the Causes of Behavior Behavior for Brain Maintenance
    • Sensory Deprivation
      • Experimental setup in which a subject is allowed only restricted sensory input; subjects generally have a low tolerance for deprivation and may even display hallucinations
      • Hebb and Heron (1950s)
        • After about 4 to 8 hours, subjects became quite distressed; few subjects lasted more than 24 hours
        • Brain has an inherent need for stimulation; one reason that we engage in behavior is to stimulate the brain
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 5. Identifying the Causes of Behavior Drives and Behavior
    • Drive
      • Hypothetical state of arousal that motivates an organism to engage in a particular behavior
    • Drive theories of motivation assume the brain is storing energy for behavior
      • “Flush” model:
        • Once a behavior is started, it will continue until all the energy in its reservoir is gone
        • There are separate stores of energy for different behaviors
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 6. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 7. Identifying the Causes of Behavior Neural Circuits and Behavior
    • Researchers have not been able to link drives and brain activity
    • What researchers have found, however, is that behavioral change correlates with changes in hormones and cellular activity
      • Example: A man’s frequency of copulation is correlated with his levels of male hormones, called androgens (male hormones related to level of sexual interest)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 8. Identifying the Causes of Behavior The Nature of Behavior: Why Cats Kill Birds
    • Why do cats kill birds even though they may be well-fed?
    • One reason is that, to secure survival, the activity of circuits such as the prey-killing circuit have become rewarding in some way: they make the cat “feel good”
      • Ensures that the cat will not go hungry
    • Killing behavior in cats is innate, not learned
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 9. Biology, Evolution, and Environment Evolutionary Influences on Behavior
    • Innate Releasing Mechanism (IRM)
    • Hypothetical mechanism that detects specific sensory stimuli and directs an organism to take a particular action
    • The brain must have a set of norms against which it can match stimuli so as to trigger an appropriate response
    • Although IRMs are prewired into the brain, they can be modified with experience
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 10. Biology, Evolution, and Environment Evolutionary Influences on Behavior
    • Evolutionary Psychology
    • Discipline that seeks to apply principles of natural selection to understand the causes of human behavior
    • Behaviors exist because the neural circuits producing them have been favored through natural selection
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 11. Biology, Evolution, and Environment The Chemical Senses
    • Olfaction
    • Receptors for Smell
      • Olfactory epithelium contains receptor cells and support cells; receptor cells send cilia into the olfactory mucosa
      • Airborne chemicals dissolve in the olfactory mucosa and interact with the cilia
        • Activation of metabotropic receptors leads to the opening of sodium channels and subsequent change in membrane potential
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 12. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 13. Biology, Evolution, and Environment The Chemical Senses
    • Olfaction
    • Olfactory Pathways
      • Olfactory cells project to the olfactory bulb, ending in tufts of dendrites called glomeruli
      • In the olfactory bulbs, synapses are formed with mitral cells , which then project to several areas of the forebrain
        • Pyriform cortex, entorhinal cortex, amygdala, hypothalamus, thalamus, and the orbitofrontal cortex
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 14. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 15. Biology, Evolution, and Environment The Chemical Senses
    • Olfaction
    • Accessory Olfactory System
      • Pheromone
        • Odorant biochemical released by one animal that acts as a chemosignal and can affect the physiology or behavior of another animal
      • Vomeronasal Organ
        • Special olfactory receptor, made up of small group of receptors that are connected by a duct to the nasal passage and detect pheromones; projects to the amygdala and hypothalamus
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 16. Biology, Evolution, and Environment The Chemical Senses
    • Human Olfactory Processing
    • Lundstrom and colleagues (2008)
      • The brain analyzes common odors and body odors differently
      • Body odors activate structures also activated by visually emotional stimuli
      • Smelling a stranger’s odor activates structures also activated by fearful visual stimuli
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 17. Biology, Evolution, and Environment The Chemical Senses
    • Gustation
    • Receptors for Taste
      • Taste receptors are found within taste buds located throughout the mouth and nasopharynx
      • Five different taste-receptor types
        • Sweet , sour , salty , bitter , and umami
      • Gustatory stimuli interact with microvilli , located on the tips of receptors, to open ion channels and alter the membrane potential
      • Taste buds connect to cranial nerves 7 (facial), 9 (glossopharyngeal) and 10 (vagus)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 18. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 19. Biology, Evolution, and Environment The Chemical Senses
    • Gustation
    • Pathways
      • Cranial nerves 7, 9, and 10 form the main gustatory, the solitary tract, from which two paths emerge
        • Splits at the thalamus and projects to the primary somatosensory cortex and the gustatory cortex of the insula (which then projects to the orbital cortex)
          • Perception of flavor
        • Hypothalamus and amygdala
          • Feeding behavior
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 20. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 21. Biology, Evolution, and Environment Environmental Influences on Behavior
    • B.F. Skinner (1904-1990)
      • Suggested a strong role of learning in behavior
      • Reinforcer
        • In operant conditioning, any event that strengthens the behavior that it follows
      • Experience shapes behavior by pairing stimuli and rewards
    • Many complex behaviors are learned, and learning takes place in a brain that has been selected for evolutionary adaptations
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 22. Biology, Evolution, and Environment Environmental Influences on Behavior
    • Learned Taste Aversion
      • Acquired association between a specific taste or odor and illness
      • Leads to an aversion to foods having that taste or odor
    • Example: Garcia (1966)
      • Coyotes were killing sheep
      • Poisoned a sheep carcass, made coyotes ill
      • Most coyotes learned never to eat sheep again
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 23. Biology, Evolution, and Environment Environmental Influences on Behavior
    • Preparedness
      • Predisposition to respond to certain stimuli differently than other stimuli
      • Brain is prewired to make certain types of associations but not others
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 24. Biology, Evolution, and Environment Inferring Purpose in Behavior: To Know a Fly
    • When studying the causes of behavior, one must be careful not to infer purpose from an organism’s actions
      • Do not assume that behavior is intentional
    • Example
      • Although a fly may look as if it is behaving with “purpose in mind,” its behaviors are controlled by a series of very simple mechanisms that are not even remotely related to our concept of thought
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 25. Neuroanatomy of Motivated Behavior
    • Critical Structures
      • Hypothalamus and associated pituitary gland
        • Sends information to other brainstem circuits to produce behavior
      • Limbic system
      • Frontal lobes
    • Homeostatic Mechanism
      • Process that maintains critical body functions within a narrow, fixed range
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12 Both project to the hypothalamus
  • 26. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 27. Neuroanatomy of Motivated Behavior Regulatory and Nonregulatory Behavior
    • Regulatory Behavior
      • Behavior motivated to meet the survival needs of the animal
      • Controlled by homeostatic mechanisms, which involve the hypothalamus
      • Examples:
        • Internal body temperature
        • Eating and drinking
        • Salt consumption
        • Waste elimination
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 28. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 29. Neuroanatomy of Motivated Behavior Regulatory and Nonregulatory Behavior
    • Nonregulatory Behavior
      • Behavior unnecessary to meet the basic survival needs of the animal
      • Not controlled by homeostatic mechanisms
      • Most involve the frontal lobes more than the hypothalamus
      • Strongly influenced by external stimuli
      • Examples:
        • Sexual behavior, parental behavior, aggression, food preference, curiosity, and reading
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 30. Neuroanatomy of Motivated Behavior The Regulatory Function of the Hypothalamic Circuit
    • Involvement in Hormone Secretions
      • A principal function is to control the pituitary gland
    • Pituitary Gland
      • Endocrine gland attached to the bottom of the hypothalamus
      • Its secretions control the activities of many other endocrine glands
      • Known to be associated with biological rhythms
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 31. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 32. Neuroanatomy of Motivated Behavior The Regulatory Function of the Hypothalamic Circuit
    • Involvement in Hormone Secretions
    • Three regions of the hypothalamus
    • Lateral Region
    • Medial Region
    • Paraventricular Region
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 33. Neuroanatomy of Motivated Behavior The Regulatory Function of the Hypothalamic Circuit
    • Involvement in Hormone Secretions
    • Lateral Region
      • Contains nuclei and nerve tracts that connect the lower brainstem to the forebrain
      • Medial Forebrain Bundle (MFB)
        • Tract that connects structures in the brainstem with various parts of the limbic system
        • Forms the activating projections form the brainstem to the basal ganglia and frontal cortex
        • Dopamine-containing fibers are involved in reward and therefore contribute to many motivated behaviors
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 34. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 35. Neuroanatomy of Motivated Behavior The Regulatory Function of the Hypothalamic Circuit
    • Involvement in Hormone Secretions
    • Posterior Pituitary
      • Neural tissue; continuation of the hypothalamus
    • Anterior Pituitary
      • Glandular tissue; synthesizes various hormones
    • Releasing Hormones
      • Peptides that are released by the hypothalamus and act to increase or decrease the release of hormones from the anterior pituitary
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 36. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 37. Neuroanatomy of Motivated Behavior The Regulatory Function of the Hypothalamic Circuit
    • Factors involved in controlling hypothalamic hormone-related activity
      • Feedback Loops
        • Control the amount of hormone that is released
      • Neural Regulation
        • Other brain regions (e.g., limbic system and frontal lobes) influence hormone release
      • Experiential Responses
        • Experience can alter the structure and function of hypothalamic neurons
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 38. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 39. Neuroanatomy of Motivated Behavior The Regulatory Function of the Hypothalamic Circuit
    • Involvement in Generating Behavior
    • Electrical stimulation of different nuclei in the hypothalamus will produce goal-directed behaviors, such as:
      • Eating and drinking
      • Digging
      • Displaying fear
      • Predatory or attack behavior
      • Reproductive behavior
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12 Indistinguishable from normally occurring behaviors
  • 40. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 41. Neuroanatomy of Motivated Behavior The Organizing Function of the Limbic Circuit
    • The primitive limbic cortex comprises:
    • Cingulate gyrus
    • Hippocampal formation
      • Hippocampus
        • Distinctive three-layered subcortical structure of the limbic system lying in the medial temporal region of the temporal lobe
        • Plays a role in species-specific behaviors, memory, and spatial navigation
        • Vulnerable to the effects of stress
      • Parahippocampal cortex
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 42. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 43. Organization of the Limbic Circuit Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 44. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12 Organization of the Limbic Circuit
  • 45. Neuroanatomy of Motivated Behavior The Organizing Function of the Limbic Circuit
    • Amygdala
      • Almond-shaped collection of nuclei located within the limbic system
      • Plays a role in emotional and species-specific behaviors
      • Receives input from all sensory systems
      • Many neurons respond to more than one sensory modality (multimodal)
      • Sends projections primarily to the hypothalamus and brainstem
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 46. Neuroanatomy of Motivated Behavior The Executive Function of the Frontal Lobes
    • The Frontal Lobe Has Three Main Regions
    • Motor Cortex
      • Controls fine movements
    • Premotor Cortex
      • Selection of appropriate movement sequences
    • Prefrontal Cortex
      • Involved in specifying the goals toward which movement should be made
      • Dorsolateral and inferior regions
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 47. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 48. Neuroanatomy of Motivated Behavior The Executive Function of the Frontal Lobes
    • Prefrontal Cortex
      • Receives connections from the amygdala, the dorsomedial thalamus, the posterior parietal (sensory association) cortex, and the dopaminergic cells of the ventral tegmental area
        • Dopaminergic input influences how prefrontal neurons react to stimuli, especially emotionally arousing stimuli
      • Inferior region projects to the amygdala and the hypothalamus: Influences autonomic nervous system
      • Dorsolateral region projects to the posterior parietal cortex, the cingulate cortex, the basal ganglia, and the premotor cortex: Influences movement and memory
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 49. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 50. Stimulating Emotion Explanations for Emotion
    • Three Components of Emotion
    • Autonomic Response (e.g., increased heart rate)
      • Hypothalamus and associated structures
    • Subjective Feelings (e.g., fear)
      • Amygdala and parts of frontal lobes
    • Cognitions (e.g., thoughts about the experience)
      • Cerebral cortex
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 51. Stimulating Emotion Explanations for Emotion
    • James-Lange View of Emotion
      • Physiological changes produced by the autonomic nervous system come first, and the brain interprets these changes as an emotion
      • Evidence: Intensity of emotions in individuals with spinal cord damage depends upon the level at which the spinal cord is severed
    • Somatic Marker Hypothesis (Damasio, 1999)
      • Posits that “marker” signals arising from emotions and feelings act to guide behavior and decision making, usually an unconscious process
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 52. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 53. Stimulating Emotion The Amygdala and Emotional Behavior
    • Involved in species-specific behaviors and emotion
    • Influences autonomic and hormonal responses via connections with the hypothalamus
    • Influences conscious awareness of the consequences of events and objects via connections with the prefrontal cortex
    • Kl ü ver-Bucy Syndrome
      • Behavioral syndrome, characterized especially by hypersexuality, that results from bilateral injury to the temporal lobe
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 54. Stimulating Emotion The Amygdala and Emotional Behavior
    • Kl ü ver-Bucy Syndrome
    • Symptoms in monkeys
      • Tameness and loss of fear
      • Indiscriminate dietary behavior
      • Greatly increased autoerotic, homosexual, and heterosexual activity with inappropriate object choice
      • Tendency to attend to and react to every visual stimulus
      • Tendency to examine all objects by mouth
      • Visual agnosia (inability to recognize objects)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 55. Stimulating Emotion The Prefrontal Cortex and Emotional Behavior
    • Damage to the prefrontal cortex has severe effects on social and emotional behavior
      • Inability to experience and express their own emotions and to recognize the emotional expression of others
      • Apathy and loss of initiative or drive
      • Inability to plan and organize, leading to poor decision-making
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 56. Stimulating Emotion Emotional Disorders
    • Depression
      • Abnormal regulation of feelings of sadness and happiness
      • Although the cause is unknown, there is a genetic component
      • Biological abnormality
        • About 70% of depressed people respond to antidepressants, many of which increase synaptic levels of noradrenaline and serotonin
        • Limbic and prefrontal regions may be involved
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 57. Stimulating Emotion Emotional Disorders
    • Generalized Anxiety Disorder
      • Persistently high levels of anxiety often accompanied by maladaptive behaviors to reduce anxiety; thought to be caused by chronic stress
    • Phobia
      • Clearly defined dreaded object or greatly feared situation
    • Panic Disorder
      • Recurrent attacks of intense terror that come on without warning and without apparent relation to external circumstances
    • Most common treatment are the benzodiazepines, which augment GABA’s inhibitory effect
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 58. Control of Regulatory Behavior Controlling Eating
    • Eating disorders entail being either overweight or underweight
    • Obesity
      • Excessive accumulation of body fat
    • Anorexia Nervosa
      • Exaggerated concern with being overweight that leads to inadequate food intake and often excessive exercising; can lead to severe weight loss and even starvation
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 59. Control of Regulatory Behavior Controlling Eating
    • The Digestive System
    • Mouth, stomach, intestine, gall bladder, pancreas, and anus
    • Three types of nutrients are extracted, each of which is a specialized form of energy reserve:
      • Lipids (fats)
      • Amino acids (building blocks of proteins)
      • Glucose (sugar)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 60. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 61. Control of Regulatory Behavior Controlling Eating
    • Hypothalamus
    • Aphagia
      • Failure to eat; may be due to an unwillingness to eat or to motor difficulties, especially with swallowing; observed following lesions to the lateral hypothalamus
    • Hyperphagia
      • Disorder in which an animal overeats, leading to significant weight gain; observed following lesions to the ventromedial hypothalamus or the paraventricular nucleus of the hypothalamus
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 62. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 63. Control of Regulatory Behavior Controlling Eating
    • Cognitive Factors
    • Amygdala
      • Projects to the hypothalamus; damage alters food preferences and abolishes taste-aversion learning
    • Inferior Prefrontal Cortex
      • Receives input from the olfactory bulb; damage may result in decreased eating because of diminished sensory responses to food odor and perhaps taste
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 64. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 65. Control of Regulatory Behavior Controlling Drinking
    • Two Kinds of Thirst
    • Osmotic Thirst
      • Results from an increased concentration of chemicals, known as solutes , in body fluids
      • Drink water to restore ideal solute concentrations
    • Hypovolumic Thirst
      • Produced by a loss of overall fluid volume from the body
      • Drink fluids, other than water, to restore nutrients
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 66. Control of Nonregulatory Behavior Effects of Sex Hormones on the Brain
    • Organizing Effects of Sex Hormones
    • Sexual Dimorphism
      • Differential development of brain areas in the two sexes
      • Influenced by gonadal hormones (testosterone, estradiol)
      • Estradiol masculinizes the male brain
        • Aromatase converts testosterone to estradiol
        • Alpha fetoprotein prevents estrogen from entering neurons
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 67. Control of Nonregulatory Behavior Effects of Sex Hormones on the Brain
    • Activating Effects of Sex Hormones
    • Adult female sexual behavior varies across the estrous cycle
      • High estrogen levels are associated with sexual receptivity
      • Rats: high estrogen is also associated with more dendritic spines on neurons in the hippocampus
    • In adult males, testosterone levels influence the motivation to seek sexual behavior and the production of copulatory behavior
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 68. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 69. Control of Nonregulatory Behavior The Hypothalamus, the Amygdala, and Sexual Behavior
    • Ventromedial Hypothalamus
      • Controls female mating posture (lordosis)
    • Preoptic Area of the Medial Hypothalamus
      • Controls copulatory behavior in males, but not sexual motivation
    • Amygdala:
      • Controls sexual motivation in males and possibly in females, as well (outside of their estrous cycle)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 70. Control of Nonregulatory Behavior Sexual Orientation, Sexual Identity, and Brain Organization
    • Sexual Orientation
    • A person’s sexual attraction either to the opposite sex or to the same sex or to both sexes
    • Sexual Identity
    • A person’s feeling either male or female
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 71. Control of Nonregulatory Behavior Sexual Orientation, Sexual Identity, and Brain Organization
    • Sex-Related Differences in Hypothalamus
      • Compared with heterosexual females, in heterosexual males, the
        • Preoptic area contains twice as many neurons
        • Bed nucleus of the stria terminalis is 2.5 times larger
        • INAH3 region is 2 times larger
        • Suprachiasmic nucleus contains twice as many neurons
      • The hypothalamus of homosexual males differs from those in both males and females, suggesting a “third sex” with respect to hypothalamic structure
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 72. Control of Nonregulatory Behavior Sexual Orientation, Sexual Identity, and Brain Organization
    • Genetic Basis?
      • Hamer and colleagues (1993)
      • In a sample of 114 homosexual males, there was a higher-than-average incidence of male homosexuality on the maternal side of the men’s families but not on the paternal side
      • Potential involvement of the X chromosome
      • But, genes specify proteins, not sexual behavior
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 73. Control of Nonregulatory Behavior Cognitive Influences on Sexual Behavior
    • In addition to the amygdala and hypothalamus, the cortex must also have a role in controlling sexual behavior
    • However, the role of the cortex in sexual behavior is poorly understood
    • Damage to the frontal lobes can result in a loss of inhibition about sexual behavior or a loss of libido (sexual interest)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 74. Reward
    • Reward may be a mechanism that evolved to help increase the adaptive fitness both of the entire species and of individual members of a species
      • Maintain contact with some stimuli but not others
    • Olds and Milner (1954)
      • Rats will press a bar to self-administer electrical stimulation to specific sites in the brain (intracranial self-stimulation)
        • Lateral hypothalamus and medial forebrain bundle are especially effective (part of mesolimbic dopamine system)
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 75. Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 76. Reward
    • Evidence that mesolimbic system is involved in reward
      • Dopamine is released during intracranial self-stimulation
      • Drugs that enhance dopamine release increase self-stimulation, whereas drugs that decrease dopamine decrease self-stimulation
      • Levels of dopamine increase when animals engage in behaviors such as feeding and sexual activity
      • Highly addictive drugs such as nicotine and cocaine increase the level of dopamine in the nucleus accumbens
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12
  • 77. Reward
    • Reward has two independent processes: wanting (incentive) and liking (evaluation of pleasure)
    • Usually, wanting and liking occur together but this is not always the case
    • Robinson and Berridge (2008)
      • Wanting and liking have separable neural systems
        • Wanting: Involves dopamine
        • Liking: Involves opioid and benzodiazepine-GABA systems
    Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12