The feeling of being on drugs can be induced by firing light into the brain, scientists have found.
Researchers from Stanford University were able to induce a state similar to ketamine by making certain brain cells activate in a particular rhythm.
They managed to achieve the state in mice, and one human being.
"There was a rhythm that appeared, and it was an oscillation that appeared only when the patient was dissociating," says Dr. Karl Deisseroth told NPR.
Disassocitation is when a person feels disconnected from themselves and the world around them.
Dissociative drugs, such as ketamine, can induce dream-like states, hallucinations, or trances.
Some have depressant effects, while others can induce euphoria – a feeling of great pleasure.
The research is "a big leap forward in understanding how these drugs produce this unique state," said Dr. Ken Solt, an anesthesiologist at Harvard Medical School and Massachusetts General Hospital.
The unexpected discovery was made when Deisseroth was studying the brain activity of mice which had been given ketamine.
"It was like pointing a telescope at a new part of the sky," Deisseroth said. "Something really unexpected jumped out at us."
In the mice’s brain, an observatble rhythm was being produced. Cells associated with learning and navigation were firing three times each second.
The scientisits were also able to recreate this effect with a human patient, who had a form of epilepsy that caused dissosotiation.
The doctors temporarily implanted electrodes in the patient’s brain, similar to how they had monitored the mice, and delivered pulses of electricity to their areas where they had seen the cells firing in the rodents.
The patient immediately reported experiencing an out-of-body experience.
While drugs like ketamine are illegal in the UK, the ability to control dissociation without drugs could be benefical to patients, the scientists said.
"In the operating room we'd love to have a drug like ketamine that just produces the pain-killing properties without having these other psychological manifestations," Dr Solt said.
Ketamine appears to help people with severe depression, as well as those with certain mental illnesses or need to recover from trauma.
While the research shows how mammals are able to dissociate themselves, it is unclear evolutionarily why we have this ability.
The research appears to explain how mammal brains are able to temporarily decouple mind and body, though it's still not clear why they have this ability.
It also could lead to ways to control dissociation without using drugs, which could eventually help a wide range of patients, Solt says.