Lucid dreaming is a rare state of being able to actively control one’s dreams. The rare, mysterious and unexplained nature of lucid dreams has intrigued scientists for centuries, and have caused it be the focus of a new study.

Researchers at the University of Wisconsin have discovered a way to induce lucid dreaming in their participants using gentle, electrical currents of electricity. The idea for the experiment stems from the fact that brain waves change distinctly during lucid dreaming. Waves from the lower gamma frequency band, with a frequency around 40 Hz, are known to accompany the state of lucid dreaming, specifically.

The sleep study, published in Nature Neuroscience, involved using a technology known as frontotemporal transcranial alternating current (tACS). Electrodes were placed on the scalp of 27 participants to deliver a current of a specific frequency to their brains. Participants were then woken at various phases of their sleep cycle to be asked about their dreams. The control group involved giving participants a placebo treatment, for the sake of comparison.

The results showed that at frequencies of 40 Hz, and occasionally at 25 Hz, participants were indeed in states of lucid dreaming. “I was dreaming about lemon cake. It looked translucent, but then again, it didn’t. It was a bit like in an animated movie, like the ‘Simpsons,’ ” said one participant. “Then I realized ‘Oops, you are dreaming.’ I mean, while I was dreaming! So strange!”

The procedure shows hope as a form of treatment for various mental illnesses, including certain types of schizophrenia, obsessive-compulsive disorder (OCD), and even post-traumatic stress disorder (PTSD). “Finally, promoting gamma oscillations during REM (rapid eye movement) sleep in post-traumatic stress disorder with reemerging nightmares might trigger lucid dreaming and eventually enable active changes in dream content,” said researchers.