It all began in the 1950s, when two scientists, Olds and Milner, conducted a decisive experiment that revealed the heart of the reward circuit. Olds and Milner implanted electrodes in the nucleus accumbens of a rat’s brain. When the rat pressed a lever, it stimulated its own nucleus accumbens. Once the rat discovered the trick, it kept stimulating itself endlessly, without even stopping to eat.
People with dependencies do exactly the same thing, except
that instead of stimulating themselves with an electrode,
they do so by taking drugs or engaging in a particular