Pleasure centers

Pleasure center is the general term for the set of brain structures, predominately the nucleus accumbens, theorized to produce great pleasure when stimulated electrically. Some references state that the septum pellucidium is generally considered to be the pleasure center while others mention the hypothalamus when referring to pleasure center for intracranial stimulation.

The nucleus accumbens, part of the limbic system, plays a role in sexual arousal and the "high" derived from certain recreational drugs. These responses are heavily modulated by dopaminergic projections from the limbic system. Rats in Skinner boxes with metal electrodes implanted into their nucleus accumbens will repeatedly press a lever which activates this region, and will do so in preference over food and water, eventually dying from exhaustion.

The limbic system is also tightly connected to the prefrontal cortex. Some scientists contend that this connection is related to the pleasure obtained from solving problems. To cure severe emotional disorders, this connection was sometimes surgically severed, a procedure of psychosurgery, called a prefrontal lobotomy (this is actually a misnomer). Patients who underwent this procedure often became passive and lacked all motivation.

In rodent physiology, scientists reason that the medial forebrain bundle is the pleasure center of rats. If a rat is given the choice between stimulating the forebrain or eating, it will choose stimulation to the point of exhaustion.