The drug-action atlas

Enter through a molecule, a synapse, or a brain circuit. Change the conditions and trace what happens next.

All learning models

Explore the system

Reward, learning, cues, and control

Explore the mesolimbic circuit, then compare natural reinforcement, drug effects, adaptation, and cue-driven activity.

Reward, learning, cues, and control

Diagram zoom

Relative receptor availability

Natural reward · new

Natural reinforcement changes with prediction and satiation. This trace illustrates a learning relationship, not a recorded experiment.

Amygdala: emotional significance · hippocampus: context memory · PFC: planning/control

Diagram zoom

Tonic · background dopamine activityPhasic · burst activity

Mechanism and exceptions

Learning can shift a phasic response toward a predictive cue; tonic background and phasic bursts are different signals.
Time (hours)	Tonic · background dopamine activity	Phasic · burst activity
0	18	18
16,7	18	18
33,3	18	18
50	18	23,85
66,7	18	36,17
83,3	18	18
100	18	18

Learning can shift a phasic response toward a predictive cue; tonic background and phasic bursts are different signals.

Evidence and limitations of the brain-disease model

The source describes circuit changes and learned cue responses, but questions dopamine-only accounts, the direction of cause and consequence in receptor differences, and the sufficiency of brain changes to explain addiction. Findings differ by drug and study. Genetic, psychological, social, and environmental conditions matter; physical dependence alone is not addiction.

Explore a circuit conditionPrefrontal control100

Animate the diagram

On a small screen, pan the diagram or increase zoom. Named controls provide the same exploration by keyboard.

Sources and model limits

Original schematic. Positions show relationships; structures and concentrations are not to scale.

Julien's Primer of Drug Action · 15 · 4 · Reward, learning, cues, and control · PDF 46, 47, 48, 49, 50, 51 · 4.1, 4.2, 4.3, 4.4

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The drug-action atlas

Enter through a molecule, a synapse, or a brain circuit. Change the conditions and trace what happens next.

All learning models

Explore the system

Reward, learning, cues, and control

Explore the mesolimbic circuit, then compare natural reinforcement, drug effects, adaptation, and cue-driven activity.

Reward, learning, cues, and control

Diagram zoom

Relative receptor availability

Natural reward · new

Natural reinforcement changes with prediction and satiation. This trace illustrates a learning relationship, not a recorded experiment.

Amygdala: emotional significance · hippocampus: context memory · PFC: planning/control

Diagram zoom

Tonic · background dopamine activityPhasic · burst activity

Mechanism and exceptions

Learning can shift a phasic response toward a predictive cue; tonic background and phasic bursts are different signals.
Time (hours)	Tonic · background dopamine activity	Phasic · burst activity
0	18	18
16,7	18	18
33,3	18	18
50	18	23,85
66,7	18	36,17
83,3	18	18
100	18	18

Learning can shift a phasic response toward a predictive cue; tonic background and phasic bursts are different signals.

Evidence and limitations of the brain-disease model

Explore a circuit conditionPrefrontal control100

Animate the diagram

On a small screen, pan the diagram or increase zoom. Named controls provide the same exploration by keyboard.

Sources and model limits

Original schematic. Positions show relationships; structures and concentrations are not to scale.

Julien's Primer of Drug Action · 15 · 4 · Reward, learning, cues, and control · PDF 46, 47, 48, 49, 50, 51 · 4.1, 4.2, 4.3, 4.4