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An Introduction to Brain and Behavior Third Edition

CHAPTER

What Causes Emotional and Motivated Behavior?

12

PowerPoints prepared by: Paul Smaldino, UC Davis, Department of Psychology

Bryan Kolb & Ian Q. Whishaw

Kolb & Whishaw, An Introduction to Brain and Behavior, Third Edition - Chapter 12

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


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


Identifying the Causes of BehaviorBehavior 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


Identifying the Causes of BehaviorDrives 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



Identifying the Causes of BehaviorNeural 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)


Identifying the Causes of BehaviorThe 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


Biology, Evolution, and EnvironmentEvolutionary 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


Biology, Evolution, and EnvironmentEvolutionary 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


Biology, Evolution, and EnvironmentThe 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




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




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



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



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)




Gustation

• Pathways– Cranial nerves 7, 9, and 10 form the main

gustatory, the solitary tract, from which two paths emerge

1. 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

2. Hypothalamus and amygdala – Feeding behavior



Biology, Evolution, and EnvironmentEnvironmental 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



• 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



• Preparedness– Predisposition to respond to certain stimuli

differently than other stimuli

– Brain is prewired to make certain types of associations but not others


Biology, Evolution, and EnvironmentInferring 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


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

Both project to the hypothalamus



Neuroanatomy of Motivated BehaviorRegulatory 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



Neuroanatomy of Motivated BehaviorRegulatory 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


Neuroanatomy of Motivated BehaviorThe 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




Circuit

Involvement in Hormone Secretions

Three regions of the hypothalamus

• Lateral Region

• Medial Region

• Paraventricular Region



CircuitInvolvement 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




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




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




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

Indistinguishable from normally

occurring behaviors



Neuroanatomy of Motivated BehaviorThe 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



Organization of the Limbic Circuit


Organization of the Limbic Circuit


Neuroanatomy of Motivated BehaviorThe 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


Neuroanatomy of Motivated BehaviorThe 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



Neuroanatomy of Motivated BehaviorThe 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



Stimulating EmotionExplanations 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


Stimulating EmotionExplanations 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



Stimulating EmotionThe 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

• Klüver-Bucy Syndrome– Behavioral syndrome, characterized especially by

hypersexuality, that results from bilateral injury to the temporal lobe


Stimulating EmotionThe Amygdala and Emotional Behavior

Klüver-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)


Stimulating EmotionThe 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


Stimulating EmotionEmotional 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


Stimulating EmotionEmotional 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


Control of Regulatory BehaviorControlling 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



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)




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




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



Control of Regulatory BehaviorControlling 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


Control of Nonregulatory BehaviorEffects 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


Control of Nonregulatory BehaviorEffects 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



Control of Nonregulatory BehaviorThe 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)


Control of Nonregulatory BehaviorSexual 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



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



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


Control of Nonregulatory BehaviorCognitive 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)


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)



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


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

Education

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