Causes of Emotional and Motivated Behavior

Introduction

• Understanding emotional and motivated behavior involves various aspects:

  • Identifying the causes of behavior.

  • The role of chemical senses.

  • Neuroanatomy involved in emotional and motivated behavior.

  • Control mechanisms for regulatory behavior.

  • Sexual differences in behavior.

  • Neural mechanisms controlling emotions.

  • Concepts of reward in behavior.

Identifying the Causes of Behavior

• Emotions: Complex reactions that involve subjective feelings, physiological responses, and behavioral responses to stimuli.

• Motivation: Refers to the driving forces behind actions that seem purposeful and goal-directed.

• Neuroanatomy in Emotion and Motivation:

  • Key structures include the hypothalamus, limbic system, and frontal lobes.

Behavior for Brain Maintenance

• Research on Rhesus monkeys showed:

  • Monkeys engaged in visual exploration by opening doors to observe stimuli, indicating a strong motivation for visual stimulation.

  • Time spent looking increased after deprivation, showing the importance of visual rewards.

Neural Circuits and Behavior

• Brain circuits for rewards can be modulated:

  • Hormonal influences and chemical senses (smell and taste) significantly affect behavior.

  • The underlying reasons for behavioral changes lie in the activity of brain circuitry.

Evolutionary Influences on Behavior

• Examines how evolution shapes brain function affecting behavior.

• Innate Releasing Mechanism (IRM):

  • A hypothetical system that responds to specific stimuli, triggering particular actions.

  • IRMs can be modified through experiences but are prewired into the brain.

Examples of IRM:

• Coyotes develop aversions to sheep after illness from eating poisoned carcasses, showing learned behavior linked to survival.

The Chemical Senses

• Chemical senses (smell and taste) play critical roles in emotional and motivated behavior:

  • Chemosignals help in social interactions, territorial marking, and food identification.

Olfactory System

• Humans can identify a vast range of odors; however, they struggle to describe smells due to their subjective nature.

• Receptors for Smell:

  • Olfactory receptors interact with chemical substances, leading to neural activation in the olfactory bulb.

Gustation

• Taste receptors identify five basic tastes: sweet, sour, salty, bitter, and umami (sensitive to glutamate).

Neuroanatomy of Motivated Behavior

• Structures critical for motivation:

  • Hypothalamus: Regulates behaviors to maintain homeostasis.

  • Limbic System: Involved in emotional processing and motivations.

  • Frontal Lobes: Contribute to complex decision-making and regulatory behaviors.

Categories of Motivated Behavior

• Regulatory Behaviors: Necessary for survival (e.g., eating, drinking).

• Nonregulatory Behaviors: Not critical for survival (e.g., curiosity, play).

Hypothalamus and Hormonal Control

• The nervous and endocrine systems governed by the hypothalamus control motivated behaviors:

  • Posterior Pituitary: Releases hormones contributing to behavioral responses.

  • Anterior Pituitary: Receives signals from the hypothalamus to regulate various bodily functions.

Hormones Influencing Behavior

• Common hormones produced by the anterior pituitary include:

  • Adrenocorticotrophic hormone (ACTH) – regulates adrenal cortex activity.

  • Prolactin – affects mammary gland function.

  • Growth hormone (GH) – stimulates growth.

Control of Eating and Drinking

Controlling Eating

• The hypothalamus plays a significant role:

  • Aphagia: Failure to eat due to lateral hypothalamic damage.

  • Hyperphagia: Excessive eating resulting from ventromedial hypothalamic damage.

Two Types of Thirst

• Osmotic Thirst: Triggered by high solute concentration in body fluids.

• Hypovolemic Thirst: Triggered by loss of fluid volume.

Sexual Differences and Sexual Behavior

• Hormonal actions lead to sexual differentiation during development; males and females exhibit different behaviors and physiological traits.

• Hormonal Effects during adulthood stimulate contextual behavioral expressions, such as mating behaviors in response to hormonal fluctuations.

Neural Control of Emotion

• Emotions consist of three components:

  • Autonomic responses (e.g., heart rate).

  • Subjective feelings (e.g., fear).

  • Cognitive assessments (thoughts about emotional experiences).

Theories of Emotion

• James-Lange Theory: Emotions arise from physiological changes.

• Appraisal Theory: Emotions as processes, incorporating evaluations and reactions to stimuli.

The Reward System

• The reward mechanism may have evolved for species fitness enhancement.

• Research by Olds and Milner showed direct brain stimulation leads to reward-seeking behavior.

Dopamine and Reward

• Dopamine plays a critical role in the experience of pleasure and reinforcement in seeking rewarding stimuli.

Distinguishing Between Wanting and Liking

• Wanting: Associated with dopamine activity for incentive.

• Liking: Evaluative pleasure related to opioid and benzodiazepine systems.

Conclusion

• Understanding emotional and motivated behavior requires an interdisciplinary approach encompassing biology, psychology, and evolutionary theory. The interplay of neuroanatomy, hormones, and environmental influences shapes behavior.