Love On The Brain: The Neurobiology of Love

Love On The Brain: The Neurobiology of Love

Romantic love is a complex set of emotions involving intense feelings of affection, passion, attachment, and longing for emotional and physical closeness with the loved one. It’s a fascinating feeling and just as fascinating a field of research. 

The neuroscience of love aims at understanding why and how people fall in love and stay in love, as well as the brain processes that underlie romantic connections. One of the leading researchers in the field was the late Helen Fisher, a biological anthropologist at The Kinsey Institute, Indiana University. We had the privilege of hosting Helen Fisher on our Collective Insights podcast where she spoke at length about the neurochemistry of love, lust, and attachment. 

If you’d like to learn about what happens in your brain when you fall in love and how it changes over time, we invite you to listen to our conversation with Helen Fisher. But in the meantime, here’s an overview of what happens in the brain when we fall in love. You can also read more about Helen Fisher’s work, here or watch her TED Talk: The Brain In Love

Neuroscience of Love

Love involves multiple brain processes, neurotransmitters, and hormones with great influence on human behavior and physiological responses [1–4]. In recent decades, the development of brain imaging techniques such as functional MRI (fMRI) has allowed researchers to visualize the regions of the brain that are activated by romantic love and how they differ across different stages of a romantic relationship. Knowing which brain regions are active has also allowed researchers to have a better insight into which neurotransmitters and neuromodulators may play a key part in the neurobiology of love.

Falling in Love: Dopamine, Oxytocin, Serotonin, and More

Studies using fMRI have revealed that, in the early-stage of romantic love, regions of the brain’s reward system seem to play a key part in the development of romantic feelings [5,6]. For example, a 2005 study by Helen Fisher’s team (the first fMRI study of the brains of individuals in the early phase of intense romantic love) showed that simply looking at a photograph of their romantic partner activated dopamine-rich areas of the reward and motivation system in participants’ brains [7]. Subsequent studies have shown similar patterns of activation in regions associated with reward [8,9].

A 2005 study showed that simply looking at a photograph of their romantic partner activated dopamine-rich areas of the reward and motivation system in participants’ brains.

The reward system refers to the neural network that mediates behaviors motivated by pleasure. Dopamine, the “feel good” neurotransmitter well known for its role in pleasure and motivation, is its main neurotransmitter [10–12]. Activation of the reward system may be involved in the perception of love as pleasurable, leading us to seek out contact with our love interest to experience more of that pleasure, and in turn leading to a reinforcement of the feelings of love. 

Other mediators involved in early love include the hormones oxytocin and vasopressin [1,3,4]. Oxytocin and vasopressin are two linked neuromodulators that promote social bonding, romantic attachment, and sexual behavior [13–15]. Their secretion is stimulated during sexual activity and when we fall in love and contributes to the reinforcement of the romantic bond [16,17]. 

The secretion of oxytocin and vasopressin, stimulated during sexual activity and when we fall in love, contributes to the reinforcement of the romantic bond.

Serotonin is another neurotransmitter that has been associated with romantic love. In the early phase of romantic love, a drop in serotonin levels has been reported [1,4]. Given how serotonin has been associated with the regulation of intrusive thoughts and obsessive behaviors [18], it has been hypothesized that the decline in serotonin may explain why in the early stages of love people often have an obsessive focus on their love interest and their actions [1,4]. 

Stress due to feelings of insecurity about the beginning of the relationship is also a common aspect of the process of falling in love. Accordingly, increased hypothalamic pituitary adrenal (HPA) axis activity (the brain’s regulator of stress responses) and stress hormone (cortisol) levels have been reported in people who have recently fallen in love, as compared with those who have not [19]. Interestingly, this elevation of cortisol was no longer observed 12–24 months into the relationship, indicating that heightened stress responses are specific to early stages of romantic love [19].

Long-Term Romantic Love

As love evolves and insecurities fade away, stress responses subside, but other elements of falling in love remain involved in maintaining a romantic bond, even after decades. 

A fMRI study with long-term happily married individuals reporting intense romantic love showed that, in response to photographs of their partners, there was neural activation in the same dopamine-rich regions associated with reward and motivation activated in early-stage love [20]. 

But other brain areas come into play in long-term romantic relationships. The study of long-term married individuals mentioned above also showed neural activity in regions associated with attachment [20]. Several of the regions activated in the study have a high density of oxytocin and vasopressin receptors, which therefore also play a part in long-term romantic love. 

This is in line with the idea that the attachment system, which coordinates proximity seeking, is recruited in long-term romantic love to form affectional bonds, similar to those formed early in life between parents and their children [21,22]. This is likely to contribute to the establishment of deep and stable emotional connection between long-term romantic partners. 

Much remains to be understood about the science of love. But as science continues to unravel the mysteries of love, we gain a deeper appreciation for the ways in which our brains shape and are shaped by our relationships.

References
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