Recently, my family was invited to a church wedding. As a humanist, I used the invite as an opportunity for my son to visit a church and get an idea what all the commotion is about. During the service, the pastor started to talk about love and told everyone that the only way we can truly love is by embracing God’s love. This started me to think what do we know about love?
A quick search on the internet led me to a posting from several years ago. A researcher started a study using individuals who described themselves as having “just fallen madly in love”. Subjects were shown two photographs; one of their recent sweetheart and another of someone who they wouldn’t have strong feelings for. Their responses to these photographs were measured using fMRI. To minimize the effects of just recently falling in love on the measurements of brain activity (since in the beginning of a passionate relationship it can be difficult to not be constantly thinking about our significant others), the researchers cleansed the brain of strong emotions by showing the subjects a large number (e.g. 9437) and asking them to count backwards in increments of seven. Two parts of the brain lit up when shown their sweetheart’s photo; the caudate nucleus and the ventral tegmental area (VTA).
The caudate nucleus is a large C-shaped region of what is considered the reptilian part of the brain. Located near the center of your brain, this region evolved long before mammals proliferated. This section is known by scientists as a key part of the brain’s reward system. The more passionate the subject was, the more this region of the brain lit up.
The VTA is a central region that produces dopamine (which can eventually travel to the caudate nucleus). This neurotransmitter plays a major role in your body’s reward system. While you get that dopamine hit when thinking about your flame, keep in mind that this chemical has also been linked to psychosis. Also a variety of addictive drugs increase dopamine’s reward-related activity.
Other chemicals in the brain are thought to be involved in love. Serotonin (of which 90% of your supply is located in your gut) is suspected to be responsible for experiencing infatuation. Oxytocin has been found in increased amounts in plasma after orgasm and may play a role in sexual arousal. Just think, all this time you may have thought it was your heart that was in charge of love, but really it was your brain all along.