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Special Report
The Brain Chemistry of Love
Your heart is racing and nothing else matters? Blame the storm in your head
By Courtney Rubin

Never mind that the song contends you can’t hurry love—science says you don’t actually need to. It takes all of a fifth of a second for that truly, madly, deeply feeling to register, says a report published in the October 2010 Journal of Sexual Medicine. That’s faster than your average resting heartbeat.

Given the heart’s popular role in romance, it may be a surprise that falling and being in love are actually more of a cerebral upheaval. Research into the wonders of passion has found that a concert of chemicals act on about a dozen parts of the brain all told (not to mention countless other body parts) to create that intense rush experienced as love. In fact, those neurotransmitters flood the system so fast that it appears “your brain knows before you do that you are in love,” says Stephanie Ortigue, the Syracuse University assistant psychology professor who led the study of how fast the brains of people passionately in love lighted up when presented with the names or pictures of their significant others.

The physiological process all begins with a face. “Constituting only 5 percent of your bodily surface, it carries 95 percent of your allure,” writes anthropologist David Givens in his book Love Signals. When the eyes fall upon an engaging countenance, sensory neurons fire up in the temporal lobes, located about ear level on either side of the brain. They send signals to the thalamus, bulb-shaped masses about 2½ inches long in the lower brain where sensations like sight and touch are processed. The thalamus then sends arousal and pleasure messages to the frontal lobe, the area of the brain that helps people decide on the best course of action. Testosterone and dopamine (the neurotransmitter that’s involved in making you happy) work together to cause the lovesick person to become aroused. Palms get sweaty, the heart beats faster, a blush arises as these chemicals work on various parts of the body, including the sweat glands and genitals, and blood flow increases, explains Maryanne Fisher, a psychology professor at St. Mary’s University in Halifax, Nova Scotia, and author of The Chemistry of Love.

A pea-sized clump of cells located at the base of the brain lights up, too, researchers revealed in a 2005 brain-scanning study of people newly in love. That cell clump, the ventral tegmental area, is part of the brain’s reward and motivation systems, and, as the central refinery for dopamine, sends the powerful neurotransmitter “to higher regions, creating craving, motivation, goal-oriented behavior, and ecstasy,” says Helen Fisher, an anthropologist at Rutgers University who conducted the MRI scans of people in early-stage romantic love. It’s a bit harder to suss out “why Jack as opposed to Joe,” she adds. “That’s a metaphysical question.” Meanwhile, surging norepinephrine and dopamine induce euphoria. Norepinephrine is a stimulant, which explains “why you might notice that the sky looks brighter, or music is louder, or basically that the world seems more alive,” says Fisher.

The whole love cocktail, which also includes oxytocin, adrenaline, and vasopressin, essentially triggers several of the same systems that are activated when a person takes cocaine, says Arthur Aron, a social psychologist at Stony Brook University in New York, who has studied love. (Indeed, a 2000 study using functional magnetic resonance imaging at University College London showed that love activates the same areas of the brain as drug abuse.) Oxytocin, the cuddling chemical, is love’s superglue (it bonds mothers to their infants), adrenaline is responsible for racing hearts and restlessness, and vasopressin raises blood pressure. Vasopressin also might encourage bonding tendencies in men. In male voles, at least, it created urges for bonding and nesting when injected and when naturally activated by sex.

One key structure operating during this initial thrill of love is the nucleus accumbens, a knot of neurons in the forebrain that is part of the body’s reward system. Sex, a good dose of chocolate, and a hit of cocaine are all the sort of pleasurable trigger linked with an increase in dopamine in this region (and it’s been studied for its role in addictions). Next, the love signals jolt the two shrimp-sized caudate nuclei near the center of the brain that house 80 percent of all brain receptors for dopamine. When the caudate is flooded with dopamine, it sends signals calling out for more. “The more dopamine you get, the more of a high you feel,”says Lucy Brown, a professor in the department of neurology and neuroscience at Albert Einstein College of Medicine in New York. As the reward system of the brain kicks into high gear, “anything that the object of one’s lust does, like their touch, or even a thought of them,” causes that intense reaction, says Fisher. Signs that this is happening include a focused attention, tons of energy, mania, elation, and “needing, craving more,” she says. At the same time, the dopamine deluge lowers serotonin levels by up to 40 percent. It’s serotonin that’s in the driver’s seat when it comes to regulating impulses, unruly passions, and obsessive behavior, and a reduction can enhance the feeling of being out of control. Lowered serotonin levels, which also occur in people with obsessive-compulsive disorders, “may explain why we concentrate on little other than our partner during the early stages of a relationship,” says Domeena Renshaw, professor emeritus of psychiatry at Loyola University Chicago Stritch School of Medicine.

While all this neuronal firing is going on, the amygdala and the anterior cingulate cortex—the worry and caution centers—practically go into hibernation. So negative emotion is dulled, as is critical judgment. Says Brown: “When you’re in a relationship, you’re aware of the other person’s flaws, but your brain is telling you it’s OK to ignore them.” In other words, science is now revealing that centuries of poets have had it right: Love is blind.

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