Romantic Love: All Just Neurobiology?

This post is dedicated to my one true love.

Using functional magnetic resonance imaging (fMRI), it has been possible for several years to study the neurobiological substrate of highly subjective mental states, such as romantic love. The influential London neuroscientist Semir Zeki has written a number of papers on this matter (e.g. Zeki, FEBS Letters, 2007, 581: 2575-2579), the essence of which I will summarize briefly here.When people in love are being shown pictures of their partner, they  – regardless of gender – demonstrate characteristic fMRI activations in the medial insular cortex, the anterior cingulate and the posterior hippocampus. Subcortical activations occur in parts of the basal ganglia, including the nucleus accumbens, brain structures that play a role as part of the so-called human reward system. It is not surprising that the brain regions that are active during sexual arousal overlap with the above but are not identical. Interestingly, in people in love, which are shown pictures of their partner, the same degree of deactivations of particular cortical (frontal, temporal and parietal) brain areas can be observed. Especially the decrease in frontal brain activity can be seen as a neuronal representation of the loss of critical distance and judgment in lovers. “Love makes blind”, especially in terms of the errors and shortcomings of the loved one. Furthermore, the amygdala, which is activated during presentation of fearful stimuli, is deactivated in active young lovers. The decrease in activation of this complex network of frontal and parieto-temporal cortices and the amygdala, which is normally activated for recognition of emotions and intentions of other persons (in neurobiology called “mentalizing” or “theory of mind”), leads to the resolution of the boundaries of the amorous couple, a condition which is considered as the culmination and the ideal of romantic love. For the neutral observer, the person in love in this state acts “crazy” and incapable of critical judgment against the partner.

From a neurochemical viewpoint, the release of dopamine plays a central role in both pairing and bonding as well as during sex. Most above-mentioned brain regions that are activated in people in love have a rich dopaminergic innervation. The observation that intense romantic relationships can have addictive nature, emphasizes the importance of this neurotransmitter in the context of addiction. It is particularly noteworthy that to the degree that dopaminergic activity is increased the activity of serotonergic neurons is reduced, to a level which can be observed in people with obsessive-compulsive disorder (OCD). Lovers are “obsessed” with their partner, their thinking revolves around the loved one. The concentrations of nerve growth factor (NGF) are significantly increased in early stages of romantic love compared to people without partners and people in long-lasting partnerships, and its concentration correlates with the extent of romantic feelings. Finally, it has been known for some years that oxytocin (and partly vasopressin) are of special importance for the formation of social bonds. The concentrations of oxytocin rise dramatically especially in the phase of the pairing and bonding. Again, it is not surprising that oxytocin is released during orgasm also.

Is therefore romantic love a purely biological phenomenon? Has neurobiology also demystified this most human of all emotions? Can we generate love one day by administering drugs or stimulation of certain brain areas? Or reduce the extent of romantic feelings in the same way, if we love too “crazy”, too “blind”, too “obsessed”? Are not already with the selective serotonin reuptake inhibitors (SSRI) medications available that could reduce some excessive excrescences of love? Love, even romantic love, has a biological basis and an important function in the context of conservation of species. However, I am convinced that beyond this biological role love has an existential meaning for humans. Without this transcendent element of love there were no Werther, no Romeo and Juliet, no Anna Karenina, probably no music, no art, no literature at all. All this raises man beyond a pure biological mechanism and makes him the incomprehensible being who is constantly struggling for the meaning of his own.


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