Leap 2015

Richard Schwartz and Jacqueline Olds know a lot virtually dear. These Harvard Medical School (HMS) professors and couples therapists study how honey evolves and, too often, how it collapses.

on the brain logo.They accept too been happily married for almost iv decades.

Love may well exist one of the virtually studied, simply to the lowest degree understood, behaviors. More than 20 years agone, the biological anthropologist Helen Fisher studied 166 societies and establish evidence of romantic love—the kind that leaves one breathless and euphoric—in 147 of them. This ubiquity, said Schwartz, an HMS acquaintance professor of psychiatry at McLean Hospital in Belmont, Mass., indicates that "there'southward proficient reason to suspect that romantic dear is kept live by something basic to our biological nature."

Rewarding ourselves with love

In 2005, Fisher led a enquiry team that published a groundbreaking study that included the beginning functional MRI (fMRI) images of the brains of individuals in the throes of romantic love. Her team analyzed 2,500 encephalon scans of college students who viewed pictures of someone special to them and compared the scans to ones taken when the students looked at pictures of acquaintances. Photos of people they romantically loved caused the participants' brains to go active in regions rich with dopamine, the so-called feel-good neurotransmitter. Two of the brain regions that showed activeness in the fMRI scans were the caudate nucleus, a region associated with reward detection and expectation and the integration of sensory experiences into social behavior, and the ventral tegmental area, which is associated with pleasure, focused attention, and the motivation to pursue and acquire rewards.

The ventral tegmental expanse is part of what is known as the encephalon's reward excursion, which, coincidentally, was discovered by Olds's father, James, when she was 7 years old. This circuit is considered to be a primitive neural network, pregnant it is evolutionarily old; it links with the nucleus accumbens. Some of the other structures that contribute to the reward circuit—the amygdala, the hippocampus, and the prefrontal cortex—are exceptionally sensitive to (and reinforcing of) behavior that induces pleasure, such as sexual activity, food consumption, and drug apply.

"We know that archaic areas of the brain are involved in romantic love," said Olds, an HMS acquaintance professor of psychiatry at Boston's Massachusetts General Hospital, "and that these areas low-cal up on brain scans when talking about a loved ane. These areas tin stay lit up for a long time for some couples."

When we are falling in love, chemicals associated with the reward circuit flood our encephalon, producing a variety of physical and emotional responses—racing hearts, sweaty palms, flushed cheeks, feelings of passion and anxiety. Levels of the stress hormone cortisol increase during the initial phase of romantic love, marshaling our bodies to cope with the "crunch" at hand. As cortisol levels rising, levels of the neurotransmitter serotonin become depleted. Low levels of serotonin precipitate what Schwartz described equally the "intrusive, maddeningly preoccupying thoughts, hopes, terrors of early love"—the obsessive-compulsive behaviors associated with infatuation.

Being love-struck as well releases high levels of dopamine, a chemical that "gets the reward system going," said Olds. Dopamine activates the reward circuit, helping to make love a pleasurable experience like to the euphoria associated with utilise of cocaine or alcohol. Scientific evidence for this similarity can be constitute in many studies, including one conducted at the University of California, San Francisco, and published in 2012 inScience. That written report reported that male fruit flies that were sexually rejected drank 4 times as much alcohol as fruit flies that mated with female fruit flies. "Same reward center," said Schwartz, "different mode to get in that location."

Other chemicals at work during romantic love are oxytocin and vasopressin, hormones that take roles in pregnancy, nursing, and mother-babe attachment. Released during sex and heightened by peel-to-pare contact, oxytocin deepens feelings of zipper and makes couples feel closer to one another after having sex activity. Oxytocin, known as well every bit the love hormone, provokes feelings of delectation, calmness, and security, which are ofttimes associated with mate bonding. Vasopressin is linked to behavior that produces long-term, monogamous relationships. The differences in beliefs associated with the actions of the ii hormones may explicate why passionate dear fades every bit attachment grows.

In addition to the positive feelings romance brings, love also deactivates the neural pathway responsible for negative emotions, such every bit fear and social judgment. These positive and negative feelings involve two neurological pathways. The one linked with positive emotions connects the prefrontal cortex to the nucleus accumbens, while the other, which is linked with negative emotions, connects the nucleus accumbens to the amygdala. When we are engaged in romantic dearest, the neural machinery responsible for making critical assessments of other people, including assessments of those with whom we are romantically involved, shuts down. "That'due south the neural basis for the ancient wisdom 'love is blind'," said Schwartz.