What actually triggers love

Question to the brain

Prof. Dr. Jens Prüssner, Head of the Clinical Neuropsychology Group at the University of Konstanz:

Love comes in many different forms. There is love for your parents, your partner, your children, your close friends, and you can often talk about love for your pets. Anyone who has ever really fallen in love with someone knows that this can be an overwhelming feeling. When you are acutely in love, all other feelings take a back seat, the mood is louder for weeks and you think about the other person non-stop. As a result, a large number of chemical messenger substances change their concentrations in the brain and in the body. The adrenaline released in the adrenal medulla during the greatest infatuation directly increases the pulse. Probably for this reason the seat of the feeling of love used to be located in the heart, and in many cultures the heart continues to serve as a symbol of love (also with us). This process is the same as with an alarm reaction, we only interpret the physiological change in a far more positive way. The real origin of love is of course in the brain, where there are amazing interactions between different areas, which together cause the feeling of love.

What has to happen so that we suddenly see another person as the most important person in our life has not yet been researched very much. Here, instinctive behavior patterns that have evolved through evolution play a role that ensure the survival of the species. In addition, there are certainly more complex factors that create individual differences through personal experience. But what happens when that moment comes, there are now quite reliable findings.

In the brain, the reward system plays an important role in the development of love. When increasing dopamine levels activate receptors in the nucleus accumbens, we experience a rewarding feeling of happiness. Elevated dopamine levels are associated with motivation and drive. Many addictive substances act on the reward system like dopamine, e.g. cocaine. Symptoms of withdrawal from the drug are similar to the feelings that arise when the partner is absent for a long time or the potential partner does not return love - a “broken heart” actually causes real pain.>

On the other hand, when you are in love, the amount of serotonin (produced in the Nucleus raphe). Serotonin is best known from depression research, as disorders can lead to depressive moods or severe depression. One of the most popular antidepressant drugs, it works by artificially increasing serotonin levels. Lovesickness is similar to depression in many ways, and serotonin may play a role in this. The serotonin balance is altered in the case of psychiatric abnormalities such as obsessive-compulsive disorder, and low levels of serotonin are associated with impulsive actions and aggressiveness. Perhaps that explains the mindless behavior that some lovers display.

Another factor in being in love, especially in physical intimacy, is played by a well-researched pituitary hormone - oxytocin. It is mainly released when we are touched on the genital areas, as is the case with sexual intercourse. The result seems to be an increase in partner loyalty. In women, the release of oxytocin is stimulated both during the birth process and during breastfeeding, which leads to a stronger bond with the child. There are very interesting studies on prairie voles, which actually remain loyal to a partner for life. But if they lack oxytocin due to a mutation, they become loners.

In summary, the often overwhelming feeling of being in love, the "butterflies in the stomach", is based to a large extent on this cocktail made of various biological active ingredients. The enteric nervous system, which controls bowel activity, reacts to these substances just like the brain. The object of romantic love, especially with humans, but also with animals, is very variable. A few years ago, this was demonstrated by the courtship for a pedal boat by a male swan - he was so blinded by his brain chemistry that he thought the swan-shaped vehicle was a potential love affair.

Recorded by Andreas Grasskamp