Binge Intoxication & Positive Reinforcement

Stages of Addiction

1. Binge-Intoxication.

2. Withdrawal-Negative Affect.

3. Preoccupation-Anticipation.

major dopamine pathways

1. Nigrostriatal: Substantia Nigra to dStriatum

2. Mesolimbic: Ventral Tegmental Area to Limbic System (including, vStriatum/NAc, amygdala, hippocampus).

3. Mesocortical: Ventral Tegmental Area to Prefrontal Cortex.

the role of DA in the vStriatum

1. Hedonics: subjective experience of pleasure.

2. Incentive Salience: Sensory stimuli acquire strong motivational properties, and goal-directed actions aimed at obtaining incentives.

3. Learning/cognition: Expectation (based on experience) that a particular action will lead to attainment of an incentive (reward expectancy); Strengthening of specific stimulus-response deliver of incentive (reward learning).

4. Reward Prediction: encodes reward-prediction error

States of Dopamine cells in the VTA

1. Hyperpolarization. Completely inhibited, will not fire action potential.

2. Tonic Firing. Irregular action potentials.

3. Phasic/Burst Firing. High-level activation, resulting from afferents to the VTA (primarily GABAergic). Related to reward signaling.