Psych 221 - Reward and Motivation

classical conditioning

a learning process that occurs when two stimuli are repeatedly paired: a response which is at first elicited by the second stimulus is eventually elicited by the first stimulus alone

prediction error

new outcime - expectation

neurtransmitter that is a learning signal

dopamine

Which system contrubutes in reward and learning

Mesolimbuc Dopamine System

When does dopamine boost happen when an outcome is learned

the anticipation of the reward causes the dopamine spike, receiving the reward no longer has a big effect

dopamine firing is

sensitive to unexpected outcomes

ventral struatum tracks

prediction error values

members of the mesolimbic dopamine reward system

frontal cortex. striatum, substantia nigra, nucleus accumbent, VTA, hippocampus

Prefrontal cortex

self regulation, response inhibition, planning for the future, complex decision makings

striatum

links motivation and movement. Guides learning, responds to rewards

Mibbrain

produces dopamine; responds to surprising outcomes

Intracranial Self-Stimulation

Signals the reward center by sending electrical impulses there in the brain of mice when they press a button

Measures intrinsic reward value of brain regions

Operant Conditioning

Animal works for reward

Assesses motivation and reinforcement learning

Conditioined Place Preference (CPP)

Animal prefers chamber paired with reward

Tests associative learning and reward valuation

progressive ratio task

increasing effort required for each reward. Quantifies motivation

Pavlovian Conditioning

Neutral cue paired with reward → cue alone triggers behavior

Outcome Devaluation and Reversal Learning

Change reward value or rules. Differentiates goal-directed vs habitual behavior

Dopamine’s relationship with the nucleaus accumbens

rodents with dopamine-depleted nucleus accumbens stop working for rewards

microdialysis and optogenetics show dopamine release correlates with reward anticipation and prediction

Cue-Reinforcer Learnung

is used to model addiction, craving, and relapse as rodents learn to associate neutral cues with rewarding outcomes

Habit Formation

Repetitive behavior shilds from goal-directed to habitual responding. Is linked to dorsolateral striatum activity

medial forebrain bundle

the tract that rises from the midbrain through the hypothalams; affected at many self-stimulation sitesn

nucleus accumbens

important target for axons of medal forebrain bundle; major component of the reward circuit’ release of dopamine here produces very pleasurable feelings

VTA

plays a key role in the brain’s reward circuitry, promarily because it contains dopamine-producing neurons that project to several important areas, including the nucleus accumbens, prefrontal cortex, and amygdala

differences between wanting and liking

one is the rush of dopamine you get from anticipating a reward. The other is your enjoyment of the reward