> A few years earlier, the doctors had implanted electrodes in a central part of his reward system—namely, the nucleus accumbens. The stimulation had worked rat

> A few years earlier, the doctors had implanted electrodes in a central part of his reward system—namely, the nucleus accumbens. The stimulation had worked rather well on his symptoms, but now it was time to change the stimulator battery. Wait a minute. It seems rather strange that upregulation of dopamine would be defined as happiness. I think of happiness as cross-activation between your endocannabinoid system and endogenous opioid system.