TEL AVIV — When Lucy Brown fell in love with her current husband a decade ago, she immediately went to work. When she arrived, she lay down in the latest fMRI brain scanner, closed her eyes and thought of him.

"It's not that I was looking for scientific proof that I was in love," Brown says during a telephone interview from her office in the Albert Einstein College of Medicine in New York. "I just told myself, "There, after all these years of looking at the brains of other people in love, I can finally look at mine." And the scans of my brain really showed the same aspects as those of other people."

She recalls that the moment she thought of him, the ventral tegmental area of her brain lit up like a Christmas tree. "The frontal lobe showed a decrease in activity, the dopamine level rose considerably, and the serotonin levels dropped," she says. "Like the other patients, I lost a part of my cognitive capacity, especially my judgment and long-term planning. Later, when I looked at the results, I saw what I felt, what we all feel sometimes. I saw how love isn't just blind and addictive, but how thanks to the mix of the two, it makes us kind of stupid."

Brown, 68, is a clinical neurology and brain anatomy specialist. In the 1970s, she participated in ground-breaking research about the brain's reward system — the mechanism responsible for the feeling of pleasure in response to stimuli ranging from a sweet taste on the tongue to a message received on a social network. This mechanism is also responsible for the creation of habits and addictions.

For the last two decades, Brown has focused on a subject that preoccupies thousands of people, but something that technology couldn't verify until recently: What really happens in the brain when people fall in love, and why do these feelings make us lose all concentration and act like fools.

Brown and her research partner, anthropologist Helen Fisher, have scanned the brains of hundreds of lovesick or broken-hearted people. All were scanned during the three months after falling in love or after difficult separations.

They compared the scans, and after a long series of scientific articles, they began to carefully interpret what Brown calls "the almost complete paralysis of the decision-making system."

Cocaine, gambling and a broken heart

It is pretty simple, Brown explains. When you fall in love, basic impulses interfere with discretion, and there are chemicals released in the brain that affect perception and behavior. These chemicals have been identified over the past two decades, and their effects on mood and on mental states are now very clear.

The main culprit is dopamine. It is a hormone that millions of brain cells send each other in countless situations — from moments of problem-solving to threat response and the experience of pleasure.

But when brain cells release an irregularly large quantity of dopamine, very particular results occur: We experience euphoria and, in some extreme cases, hallucinations.

In fact, research that Brown and Fisher published in 2010 demonstrates that the way the brain reacts when we view a photo of a person we compulsively desire is similar to the way it reacts after using cocaine. "Falling in love is an addiction," Fisher told ABC after the results were published. "My guess is that modern addictions such as nicotine, drugs, sex or gambling simply capture the same internal channels which were developed millions of years ago by the brain for the feeling of romantic attraction."

Brown says it's just part of the larger picture. "This mechanism is part of the compensation system that pushes us to romantic pursuit," she says. "This obsessive and compulsive attitude that for the same reasons appears among drug addicts is maybe not good for the individual, but serves our human gender exactly like other impulses of mammals."

Brown's research suggests that between 10% and 20% of people in love are capable of staying in love for an entire lifetime. She discovered this when scanning the brains of people who said they were still in love and committed after lengthy relationships.

"The general belief in our field," Brown says, "is that people who say they are in love after a 30-year relationship will probably fail the test of brain scanning. However, to our surprise, we found that some of the older couples in our study, when exposed to a photo of their spouses, showed the same brain activity as the younger people who were deeply in love."

She says she and fellow researchers remain convinced that these people are really living a love story for decades. "When you have such a connection, it may not be so important that your judgment and the one of your partner are completely flawed because you will never see the difference anyway."