What Fisher saw fascinated her. When each subject looked at his or her loved one, the parts of the brain linked to reward and pleasure—the ventral tegmental area and the caudate nucleus—lit up. What excited Fisher most was not so much finding a location, an address, for love as tracing its specific chemical pathways. Love lights up the caudate nucleus because it is home to a dense spread of receptors for a neurotransmitter called dopamine, which Fisher came to think of as part of our own endogenous love potion. In the right proportions, dopamine creates intense energy, exhilaration, focused attention, and motivation to win rewards. It is why, when you are newly in love, you can stay up all night, watch the sun rise, run a race, ski fast down a slope ordinarily too steep for your skill. Love makes you bold, makes you bright, makes you run real risks, which you sometimes survive, and sometimes you don't.
I first fell in love when I was only 12, with a teacher. His name was Mr. McArthur, and he wore open-toed sandals and sported a beard. I had never had a male teacher before, and I thought it terribly exotic. Mr. McArthur did things no other teacher dared to do. He explained to us the physics of farting. He demonstrated how to make an egg explode. He smoked cigarettes at recess, leaning languidly against the side of the school building, the ash growing longer and longer until he casually tapped it off with his finger.
What unique constellation of needs led me to love a man who made an egg explode is interesting, perhaps, but not as interesting, for me, as my memory of love's sheer physical facts. I had never felt anything like it before. I could not get Mr. McArthur out of my mind. I was anxious; I gnawed at the lining of my cheek until I tasted the tang of blood. School became at once terrifying and exhilarating. Would I see him in the hallway? In the cafeteria? I hoped. But when my wishes were granted, and I got a glimpse of my man, it satisfied nothing; it only inflamed me all the more. Had he looked at me? Why had he not looked at me? When would I see him again? At home I looked him up in the phone book; I rang him, this in a time before caller ID. He answered.
"Hello?" Pain in my heart, ripped down the middle. Hang up.
Call back. "Hello?" I never said a thing.
Once I called him at night, late, and from the way he answered the phone it was clear, even to a prepubescent like me, that he was with a woman. His voice fuzzy, the tinkle of her laughter in the background. I didn't get out of bed for a whole day.
Sound familiar? Maybe you were 30 when it happened to you, or 8 or 80 or 25. Maybe you lived in Kathmandu or Kentucky; age and geography are irrelevant. Donatella Marazziti is a professor of psychiatry at the University of Pisa in Italy who has studied the biochemistry of lovesickness. Having been in love twice herself and felt its awful power, Marazziti became interested in exploring the similarities between love and obsessive-compulsive disorder.