People who have been swept off their feet know the feeling. Love makes us all feel funny. That sense of giddy disorientation, unsinkable euphoria and complete obsession with a new love can be so overpowering, that it's hard to imagine it's all about emotion. Now scientists are confirming there indeed may be a lot more going on in a body that's in love than simple, happy thoughts. In fact, a spate of research has shown what kind of chemical and neurological activities occur at different stages of human and animal relationships. While the results hardly make love less mysterious, they do start to shed light on why it can make people feel so funny.

DOPED UP

Helen Fisher, a research professor of anthropology at Rutgers University , is among many scientists who believe the flush of a new love is enhanced by natural stimulants in the brain, dopamine and norepinphrine. She explains that high levels of these natural chemicals can make people lose their appetites and their desire for sleep, just by thinking about their new infatuations. "These are basic traits commonly associated with romantic love and with these natural stimulants," she says. "What else could explain the way you constantly think about a person, about the way you want to read them your bad poetry?"

Further studies show that gushy romantic sensations may be similar to the highs drug addicts feel when they're under the influence. Nora Volkow; the associate director for life sciences at Brookhaven National Laboratory in New York , has analysed the behaviours of drug addicts and people in love and found striking parallels. "When a person is passionately in love, it is extremely exciting and provocative, and if the loved one is not there, distressing," says Volkow. "When I see my drug addicted patients, it just clicks with me how similar the addiction is. "The fact that drug addiction and passionate love may trigger the same responses, signals to Volkow that drug addiction is especially dangerous since it taps into a natural sensation.

STIRRING THE BRAIN

She points out that recent studies show the same regions of the brain including the frontal cortex which is activated when a drug addict is high and when someone in love is looking at a picture of a loved one. Researchers at University College in London recently recorded changes in the brains of people who described themselves as "truly and madly" in love. The researchers, Andreas Bartels and Semir Zeki used a functional magnetic resonance imager to scan the brains of 17 lovehappy volunteers. When the team showed volunteers photos of their lovers, the results were dramatic. Four small areas of the brain lit up instantly the same areas that have been shown to respond to euphoria-inducing drugs.

Old friends, apparently, don't quite cause the same stir. Fisher is conducting similar studies and is scanning the brain activity of people newly in love.

THREE STAGES OF LOVE

As most know; however, the rush people feel from new love usually doesn't last forever. And Fisher is also interested in understanding the biological stimulants and anthropological explanations for all phases of love.

She argues that there are three main stages to a love relationship: lust, romantic love and attachment. The first, she says, is "to get you looking for anything at all" and is driven by hormones like testosterone.

The romantic love phase, which creates the brain chemical reactions described by the London researchers, serves to "force you to focus your mating energy on one person at a time."

And the fmal, less steamy stage of attachment is to ensure that any children produced by a love match has parents at least through its early years.

Research shows there may also be chemicals associated with feelings of attachment. When researchers injected a natural chemical called oxytocin into the mice, the animals immediately formed attachments. When they injected chemicals that block the effect of oxytocin, Fisher says; the mice "avoided their partners and acted like cads."

Recent studies have zeroed in on the chemistry of love, revealing what kind of chemical and neurological activities occur at different stages of human and animal relationships.

Love is enhanced by natural stimulants to the brain, dopamine and noreinphrine.

Gushy romantic sensations similar to the high of drug addiction.

Regions of the brain stirred when thinking of the loved one.

The stages of lust, love and attachment are affected by body chemicals.