the lever-rat: pressing until it dies
the Canadians found that if they rigged an auto-stimulation lever, the rat would press the lever to stimulate his p-terminal over and over, thousands of times an hour, over and over, ignoring food and female rats in heat, completely fixated on the lever’s stimulation, day and night, stopping only when the rat finally died of dehydration or simple fatigue.
Context
The book's core emblem of addiction rendered in laboratory form — addiction with the substance stripped away, reduced to pure circuitry. The rat pressing its pleasure-lever "thousands of times an hour... ignoring food and female rats in heat" until it dies of dehydration is the substance-cage at its most literal: reward decoupled from survival, pleasure that outcompetes every other drive including staying alive. And the detail that removing the electrode doesn't stop the behavior — the animal still "run around pressing anything that could be pressed" — is the theme's whole thesis about the Disease outliving the drug: the compulsion is in the wiring, not the chemical, and persists after its object is gone.