#96 - Reward/Salience (1.5 hours) Flashcards
Explain the “drive reduction” theory of motivated behavior.
“Drive reduction” is based on the idea of internal “drives” driven by homeostasic disruption; an internal “drive” that one needs to reduce, like water/food.
However, this theory doesn’t explain all motivated behavior, like exploration, aggression, or mating. Binge eating, where you consume more than you need, is also not explained.
Drive motivation - focuses on internal stimuli.
Explain the “incentive motivation” theory of motivated behavior.
“Incentive motivation” revolves around the idea of a “goal” and stipulates that behavior results out of the reward of the goal.
Incentive motivation - focuses on external stimuli
What does dopamine neuron activity in the ventral tegmental area signal in regards to reward?
VTA Dopamine signals the relationship between the animal’s prediction regarding the reward and the reward itself.
This means, any time there is an unexpected “cue” or reward, dopamine firing will increase. If a cue happens but no reward is given, VTA dopa firing will decrease.
Dopamine = reward-prediction error signal.
Look at slide 18 for more info about experimental scenarios.
Basic mechanism of action for cocaine/amphetamine
They block or reverse monoamine uptake mechanisms
How is nicotine reinforced?
Its reinforcing effects are mediated through nicotinic receptors in the VTA, NOT!!! I repeat NOT!! the nucleus accumbens!
nicotinic ACh receptors are on dopamine neurons. When activated, they increase dopamine levels in the nucleus accumbens. Therefore, decreasing dopamine in the VTA will decrease reinforcement but inhibiting dopamine in the Nucleus accumbens will not.
Basic mechanism of action for cannabis - how do they increase dopamine?
Cannabinoids inhibit GABA neurons in the VTA, disinhibiting dopamine neurons.
Why do drugs of abuse thought to produce profound effects on the reinforcement system? 2 big reasons.
1) For normal stimuli, they get filtered through sensory channels, and other areas of the brain. Therefore, you get a small, regulated amt of dopamine. With drugs, they activate dopamine directly, getting an unregulated, large dose of dopamine.
2) Normally, if you do something with expected rewards, there will be no additional dopamine. With a drug, it directly activates dopamine, therefore it gets reinforced EVERY TIME you take it, at much higher levels.
Essentially, this means that every time you take the drug, there is a signal that the reward was WAY BETTER than expected!
What does drive reduction theory fail to explain, as far as human behavior goes?
this theory doesn’t explain all motivated behavior, like exploration, aggression, or mating. Binge eating, where you consume more than you need, is also not explained. Also: simply eating more than you need because something tastes good.
Which is more accurate describing human behavior, drive reduction or incentive motivation?
Neither. They both play important roles.
What does “consummatory behavior” mean?
it means the behavior that is the consummation of the set of motivated behavior - eg, drinking.
What is “appetitive behavior”?
behavior that brings the organism closer to the goal (eg, exploration, behavior to obtain food)
t/f: both internal drive and incentive objects contribute to a “motivational state” in an organism.
True!!
3 main points about motivated behavior
- motivated behavior involves learned behavoir and innate systems/drives
- Involves emotions and decision making.
- Can be directed toward achieving something positive or avoiding something negative.
How do different parts of the basal ganglia system handle different types of behavior, ie le basic/new learning vs. habits?
The accumbens core governs “goal seeking behavior,” while the dorsal striatum plays a larger role in “habit-based” behavior. Therefore, it is said that as a motivated behavior becomes learned better, the area governing the behavior moves DORSOLATERALLY.
This region of the brain is responsible for integrating emotions and other abstract motivators (ie hunger) into concrete behaviors (ie, motor sequences.)
nucleus accumbens “turns emotion into action”
T/F VTA Dopamine signals pleasure.
FALSE.
T/F VTA Dopamine signals reward.
FALSE
Simple way of describing VTA dopamine.
Dopamine = reward-prediction error signal, indicates difference between what is expected and what actually occurs.
Increases in firing = “better than expected rewards”
Decreases in firing = worse than expected rewards.
What is “incentive salience”?
Reward associated stimuli can have a motivational “wanting” effect on the organism.
Even though you are full, the waitress brings out a dessert plate and asks if you want dessert. Suddenly hungry, you order the brownie sundae. What concept led to your demise?
incentive salience!!
a cue associated with a reward (the sensory info in this case, seeing/smelling the food) can induce hunger and drive eating all on its own! even if you are full, it has a motivational wanting effect on you.
T/F Dopamine acts to stamp in associations between cues and primary reinforcers.
True.
T/F - evidence suggests that dopamine in the nucleus accumbens is critical for both learning about rewards and for driving motivated behavior.
True.
3 characteristics of addiction
- compulsion to seek and take drug
- loss of control over use.
- Negative emotional state when access to the drug is prevented.
How do drugs of abuse, in general, become addictive?
They increase dopamine levels in the brain, which is critical for the reinforcing effects. They vary in how they increase dopamine, but they all do it.
