MATT COLLINS

A fundamental goal of neuroscience has always been to deduce the brain systems that underlie such basic drives as hunger, thirst and sex. In 1956 the well-known physiologist James Olds wrote an article for Scientific American, called “Pleasure Centers in the Brain,” that described how a rat kept without food for a day was lured down a platform by a tasty meal. En route to dinner, it received a pleasurable electric shock. The rat never showed up for mealtime, instead choosing to delight in the arousal. With the optimism characteristic of that era, Olds concluded that stimulation experiments would lead to an understanding of neural functioning that would allow “one drug that will raise or lower thresholds in the hunger system, another for the sex-drive system, and so forth.”

Fifty years later the promise of Olds’s vision has yet to fully materialize. Better drugs are needed to suppress appetite and spark sexual desire. But fascination has grown in recent years with taking Olds’s more direct route of stimulating the central nervous system.

So far no one has created anything like the Orgasmatron, first seen in Woody Allen’s 1973 comedy Sleeper. Undaunted, one clinician—who has trademarked the name Orgasmatron—ran a small, FDA-reviewed pilot trial to test the possibility of applying electric current to the spine to reverse sexual dysfunction. Stuart Meloy, a North Carolina physician who specializes in implanting spinal electrodes to alleviate pain, found by chance that a slightly off-kilter placement in the lower spine caused one woman to exclaim: “You’re going to have to teach my husband to do that.”

In 2006 Meloy reported that 10 of 11 women who stopped having or never had orgasms experienced sexual arousal with the temporary implant and, of that group, four had their ability to experience orgasm restored. Meloy is seeking a medical device manufacturer to bring the costs down to $12,000 for a permanent implant, about the charge for breast enlargement.

Neural electrodes may eventually move up the spinal cord to what is often characterized as the body’s primary erogenous zone. Deep-brain stimulation, the placing of electrodes at strategic spots far underneath the skull, now treats a variety of ailments, including Parkinson’s disease and dystonia (uncontrollable twisting of a body part caused by involuntary muscle contractions). An occasional side effect is spontaneous sexual stimulation.

Tipu Aziz, a neurosurgeon at the University of Oxford, speculates that better knowledge of the brain’s pleasure centers—combined with improved surgical procedures and control of electrical pulses—may make a sex chip in the brain a reality. “Lack of sexual pleasure is a huge loss in one’s life, and if one could restore that, that would enhance someone’s quality of life enormously,” Aziz remarks.

Some neuroscientists are not so sure. Morten L. Kringelbach, a researcher at Oxford who sometimes collaborates with Aziz and wrote the book The Pleasure Center (Oxford University Press, 2008), cautions that hedonic experience may consist of an impulse corresponding to “wanting” and another that represents “liking.” To succeed as a therapy, a sex chip would have to address the challenge of switching on neural circuits that activate both impulses. In a 2008 paper in Psycho­phar­ma­col­ogy with University of Michigan at Ann Arbor psychologist Kent Berridge, Kringelbach illustrated the distinction between the two by citing an infamous case from the 1960s, in which psychiatrist Robert Heath placed “pleasure electrodes” in the brain of a gay man code-named B-19, in part, as an attempt to “cure” his homosexuality.

The patient pressed a button compulsively to turn on an electrode that induced a desire for sex, but whether he actually enjoyed the sensation was unclear. The stimulation alone did not induce orgasm, and B-19 never expressed any real contentment while hitting the button. Kringelbach warns against similar misuses of contemporary deep-brain stimulation. “It’s important that we not get carried away by this technology,” he says. “It’s important that we not end up in another era of psychosurgeries,” referring to the mid-20th century popularity of lobotomies to treat psychiatric disorders.