Chapter Introduction

CHAPTER 12

What Causes Emotional and Motivated Behavior?

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RESEARCH FOCUS 12-1 THE PAIN OF REJECTION

12-1 IDENTIFYING THE CAUSES OF BEHAVIOR

BEHAVIOR FOR BRAIN MAINTENANCE

NEURAL CIRCUITS AND BEHAVIOR

12-2 THE CHEMICAL SENSES

OLFACTION

GUSTATION

12-3 EVOLUTION, ENVIRONMENT, AND BEHAVIOR

EVOLUTIONARY INFLUENCES ON BEHAVIOR

ENVIRONMENTAL INFLUENCES ON BEHAVIOR

INFERRING PURPOSE IN BEHAVIOR: TO KNOW A FLY

12-4 NEUROANATOMY OF MOTIVATED AND EMOTIONAL BEHAVIOR

REGULATORY AND NONREGULATORY BEHAVIOR

REGULATORY FUNCTION OF THE HYPOTHALAMIC CIRCUIT

ORGANIZING FUNCTION OF THE LIMBIC CIRCUIT

EXECUTIVE FUNCTION OF THE FRONTAL LOBES

CLINICAL FOCUS 12-2 AGENESIS OF THE FRONTAL LOBES

STIMULATING AND EXPRESSING EMOTION

AMYGDALA AND EMOTIONAL BEHAVIOR

PREFRONTAL CORTEX AND EMOTIONAL BEHAVIOR

EMOTIONAL DISORDERS

CLINICAL FOCUS 12-3 ANXIETY DISORDERS

12-5 CONTROL OF REGULATORY AND NONREGULATORY BEHAVIOR

CONTROLLING EATING

CLINICAL FOCUS 12-4 WEIGHT LOSS STRATEGIES

EXPERIMENT 12-1 QUESTION: DOES THE HYPOTHALAMUS PLAY A ROLE IN EATING?

CONTROLLING DRINKING

CONTROLLING SEXUAL BEHAVIOR

CLINICAL FOCUS 12-5 ANDROGEN INSENSITIVITY SYNDROME AND THE ANDROGENITAL SYNDROME

SEXUAL ORIENTATION, SEXUAL IDENTITY, AND BRAIN ORGANIZATION

COGNITIVE INFLUENCES ON SEXUAL BEHAVIOR

12-6 REWARD

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Katherine Streeter

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RESEARCH FOCUS 12-1

The Pain of Rejection

We use words like sorrow, grief, and heartbreak to describe a loss. Loss evokes painful feelings, and the loss or absence of contact that comes with social rejection leads to hurt feelings. Several investigators have attempted to discover whether physically painful and emotionally hurtful feelings are manifested in the same neural regions.

Physical pain (say, hot or cold stimuli) is easy to inflict, but inducing equivalently severe emotional, or affective, pain is more difficult. Ethan Kross and colleagues (2011) performed an experiment that may have succeeded in balancing participants’ degree of emotional and physical pain.

Using fMRI, they scanned 40 people who had recently gone through an unwanted breakup. To compare brain activation, the participants viewed two photographs: one of their ex-partner, to evoke negative emotion, or the photo of a same-gender friend with whom the participant shared a pleasant time at about the time of the breakup. The picture order was randomized across participants.

Emotional cue phrases associated with each photograph directed the participants to focus on a specific experience they shared with each person. The physical stimulus employed by the researchers, which was administered in a separate session, was either painfully hot or painless warm stimulation of participants’ forearm.

The research question is, do physical pain and social pain have a common neuroanatomical basis? The results, shown in the illustration, reveal that four regions respond to both types of pain: the insula, dorsal anterior cingulate cortex (dACC), somatosensory thalamus, and secondary somatosensory cortex (S2). The conclusion: Social rejection hurts in much the same way physical pain hurts.

Previous studies, including Eisenberger and colleagues, 2003, 2006, showed anterior cingulate activity during the experience of both physical and emotional pain. But new results also showed activity in cortical somatosensory regions related to physical pain. The results imaged by Kross and colleagues suggest that the brain systems underlying emotional reactions to social rejection may have developed by co-opting brain circuits that support the affective component of physical pain. We hasten to point out, however, that the overlapping activity in brain regions does not rule out unique neural components of emotional experiences. Certainly our subjective experiences are unique (e.g., Woo et al., 2014).

Another insight from the Kross study is that normalizing the activity of these brain regions probably provides a basis for both physical and mental restorative processes. Seeing the similarity in brain activation during social pain and physical pain helps us understand why social support can reduce physical pain, much as it soothes emotional pain.

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Overlapping Social Rejection and Physical Pain
These fMRIs result from averaging scans from 40 participants to image the brain’s response to physical or emotional pain. We see activation in the insula, dorsal anterior cingulate cortex (dACC), somatosensory thalamus, and/or secondary somatosensory cortex (S2).
Research from E. Kross, M.G. Berman, W. Mischel, E.E. Smith, & T.D. Water, “Social rejection shares somatosensory representations with physical pain,” 2011, Proceedings of the National Academy of Sciences (USA), 108, 6270–6275.

Knowing that the brain makes emotional experience real—more than mere metaphors of hurt or pain—how do we incorporate our thoughts and reasons for behaving as we do? Clearly, our subjective feelings and thoughts influence our actions. The cognitive interpretations of subjective feelings are emotions—anger, fear, sadness, jealousy, embarrassment, joy. These feelings can operate outside our immediate awareness.

This chapter begins by exploring the causes of behavior. Sensory stimulation, neural circuits, hormones, and reward are primary factors in behavior. We focus both on emotion and on the underlying reasons for motivation—behavior that seems purposeful and goal-directed. Like emotion, motivated behavior is both inferred and subjective, and it can occur without awareness or intent. It includes both regulatory behaviors, such as eating, which are essential for survival, and nonregulatory behaviors, such as curiosity, which are not required to meet an animal’s basic needs.

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Research on the neuroanatomy responsible for emotional and motivated behavior focuses on a neural circuit formed by the hypothalamus, the limbic system, and the frontal lobes. But behavior is influenced as much by the interaction of our social and natural environments and by evolution as it is by biology. To explain how all these interactions affect the brain’s control of behavior, we concentrate on two specific examples, feeding and sexual activity. Our exploration leads us to revisit the idea of reward, which is key to explaining emotional and motivated behaviors.