Dopamine D1 receptors mediate desire. The D2 receptors mediate self-control. Addictive drugs downregulate the D2 receptors, inducing the craving and impulsivity of addiction.

Electrodes implanted in the reward pathway do not produce pleasure but craving.

Pairing a painful stimulus with activation of the amygdala train rats to want the painful stimulus, possibly explaining why masochists desire pain.

Porn is not addictive. It induces short increases of dopamine and not the sustained ones produced by cocaine and opioids.

Women with spinal cord transections experience vaginal orgasms with sensations carried by the vagus nerve.