Lect. 18 Motivation and Emotion

Adaptive Behaviors: Those that promote the survival and propagation of the organism and species. Includes:
- Individual Behaviors: Actions performed by a single organism.
- Group/Social Behaviors: Actions influenced by social dynamics or group interactions.
Maladaptive Behaviors: Not all behaviors are adaptive; some can become maladaptive, often as a consequence of brain disorders.
Question of the Day: What motivates you to engage in certain behaviors?

Need-Based Motivations:
- Hunger motivates feeding.
- Thirst motivates drinking.
- Reproductive drive motivates sexual behavior.
- Resource security motivates working.
Emotion-Based Motivations:
- Positive or pleasurable feelings motivate behaviors that lead to those feelings.
- Fear of social embarrassment, harm, or death can motivate avoidance or defensive behaviors.
- Feelings of unfairness can lead to aggressive behaviors.
Memory-Based Motivations:
- Previous experiences influence current behavior; recalling what happened the last time a behavior was performed shapes future actions based on past experiences.

Relevant Reading:
- Review dopamine system and VTA pathways (e.g., Chapter 4).
Exam Material: Primarily from lecture.

Describe how ingestive behavior and taste preferences can be altered by experience; support assertions with evidence from animal studies (MiniVideo).
Explain how motivated behaviors are shaped by reinforcement and punishment.
- Use examples to describe the four types of reinforcement and punishment.
Describe the role of VTA-NAC dopamine release in hedonically motivated feeding behavior and the supporting evidence.
Explain how hedonic appraisal is assessed.
List at least one method for measuring dopamine.
Identify dopamine-releasing vs. dopamine-receiving neurons.
Describe how dopamine manipulation can interrogate its role in hedonics and motivated behavior.
Differentiate motivated vs. habit behaviors and the brain systems involved in each.
Clarify what DA release signifies after a reward and during a reward cue.

What motivates consumption or rejection of food?
- Need: Homeostatic drive to replenish energy stores.
- Hedonic Impact: How tasty is the food?
- Learning: Past experiences influence preferences.
Phases of Motivated Behavior:
- Appetitive Phase: Behaviors necessary to acquire a reward (e.g., approach, search, work for reward).
- Consummatory Phase: Specific actions of reward consumption (e.g., eating).
Difference between reward and reinforcement, and methods for their measurement in lab models.
Investigate whether positive things can become negative due to learning.
Understand how actions evolve into habits.

Positive Reinforcement: Adds a reward, increasing the likelihood of a behavior.
Negative Reinforcement: Removal of a negative stimulus increases behavior likelihood.
Positive Punishment: Introduction of a negative stimulus reduces behavior likelihood.
Negative Punishment: Withholding a reward reduces behavior likelihood.
Reinforcer: Outcome or environmental event promoting behavior (aka motivator). Example: Lever-pressing for a reward culminates in seeking behaviors associated with rewards (appetitive behaviors) and consumption behaviors (consummatory behaviors).

Learning and Experience Influence on Taste Preferences:
- Can rewarding tastes become aversive? Yes, conditioned taste aversion (CTA) is an example.
- Can aversive tastes become rewarding? Yes, sucrose fading in ethanol is an instance.
- Do cues that predict positive taste experiences affect palatability? Yes; e.g., McDonald’s wrapper experiment demonstrates this.

Taste Stimuli and Ingestive Behavior:
- Reward pathway involves mesolimbic dopamine.
- Sweet tastes increase dopamine in the Nucleus Accumbens (NAc).
- Bitter tastes decrease dopamine in the NAc, leading to avoidance of bitter substances like quinine.

Dopamine Encoding:
- Is dopamine necessary for hedonic taste evaluation?
- Based on experiments with dopamine-depleted models that maintain taste reactivity irrespective of dopamine presence.
- Conclusion: Dopamine does not mediate the hedonic quality (liking/disliking) of tastes but plays a role in motivated behaviors and reinforcement learning.

Dopamine's Influence:
- Dopamine is implicated in more than just hedonic evaluation; it's essential for motivation and reinforcement learning.
- Dopaminergic activity indicates reward-seeking behavior (e.g., lever pressing for rewards) and performance based on target value.
Cue Responsivity and Learning:
- The brain learns to associate cues with forthcoming rewards, hence shifting dopamine responses from reward delivery to prediction cues as learning progresses.

Habit Formation:
- Mediated by dopamine signaling within the dorsal striatum.
- Responses in the NAc are sensitive to reward value; habituation occurs as exposure to predictable rewards increases.
- Definition: Habits become resistant to extinction, demonstrating outcome insensitivity and control loss.

Instrumental Learning vs. Habit Learning:
- Distinction illustrated via autoshaping where stimuli elicit responses without direct action to acquire rewards.
Extinction Training:
- Habit associations demonstrate enhanced resistance to extinction compared to instrumental responses when the cue-consequence relationship is removed.
Outcome Devaluation Effect:
- Habit learning is insensitive to devaluation; demonstrated in conditions where animals were not hungry or food was altered, reducing their relevance.

Discussion on how addiction alters brain systems:
- Fundamental changes lead to compulsive drug seeking—outcome insensitive and extinction resistant.
Recommendation: Review the end of Chapter 4 regarding substance abuse for a deeper understanding.