…there’s a simpler way to spark joy, if we really want to get literal about it. Any emotion we feel has a physical cause inside our brains. Electrical charges pass from neuron to neuron, spreading ripples of thought and feeling. What we call happiness is just electricity. And now researchers say they’ve found a remarkably specific means of triggering the electrical fireworks that add up to happiness in our brains. By electrically stimulating a brain region known as the cingulum, scientists created spontaneous laughter and a sense of calm and joy in three different patients.

The find could lead to treatments for anxiety and depression, and it hints at insights into the very roots of our emotions themselves.

The young woman is clad in hospital garb, sitting upright in a bed. A white hospital cap mushrooms above her head, wires splay from its rear. She’s due for brain surgery in a few days to treat a difficult, disruptive kind of epilepsy. She’s been worried and anxious.

The patient breaks into a radiant smile, laughter flowing uninhibited.

“I’m kind of like smiling because I can’t help it,” she says. A bit later, “Sorry, that’s just a really good feeling. That’s awesome.”

Neuroscientists just administered a tiny jolt of electricity to wires threaded through her skull and into her brain. The wires are there to guide surgeons to the source of her seizures. But before the procedure, she’s agreed to play guinea pig to a team of Emory University researchers.

Patients like her offer an unprecedented opportunity for researchers to test the workings of various brain regions with unparalleled specificity. By delivering targeted bursts of electricity through the electrodes, they can watch what happens when specific neural circuits are activated.

The team was sending small bursts of electricity to her cingulum, a horseshoe of brain matter that links to regions associated with emotion, self-assessment, social interaction and motivation, among other things. It’s also known to regulate anxiety and depression.

This kind of research, though hardly common, is not new. The patient’s reaction is.

“It was really exciting,” says Kelly Bijanki, a neuroscientist at Emory University who studies behavioural neuromodulation. She was one of the scientists working with the young woman, whose name was not given for privacy reasons, that day. She says the kind of spontaneous joy she saw was unprecedented.

Experiments with brain stimulation have elicited laughter and smiles before. But those responses seemed mechanical. Bijanki says the patients usually described it as a purely motor response. “Their body has laughed, but there’s no content to it.”

This case was different. There was real warmth behind the laughter; true happiness in her voice. At one point, the patient reported she was “so happy she could cry,” the researchers write in their paper.

“The way she was laughing was really infectious,” Bijanki says. “The whole room felt different: she was laughing, she was having a good time, and not afraid. Just that social, emotional contagion took over.”

Further tests confirmed the response. They conducted sham trials, telling the patient that they were providing stimulation when they weren’t. She didn’t react. They tested various levels of stimulation and saw that the more electricity they delivered, the stronger the joyous reaction was. The pattern remained the same: An initial burst of exultation faded into a state of happy relaxation after several seconds.

The researchers found no drawbacks to the treatment, either, they report in a paper in the Journal of Clinical Investigation. Her language skills and memory remained perfectly intact, and they saw no ill aftereffects of the stimulation…

… Bijanki was also struck by an odd side-effect of the stimulation. Though patients had no trouble recalling sad memories during treatment, the recollections were wholly powerless to make them feel unhappy.

“I remember my dog dying, and I remember that it was a sad memory, but I don’t feel sad about it right now,” the young woman said, as reported by the researchers in their paper. Another patient concurred, unable to recollect a tragic memory without smiling. The effect is slightly jarring, but it could provide a shield of sorts to those overcoming trauma.