Using their “master control switch,” a research team could shorten or lengthen REM sleep and discovered that the size of the slow waves that followed in the next bout of NREM sleep were correspondingly smaller or larger, reports The Japan Times.

Now, it seems, our understanding of sleep has taken another important step forward. Yu Hayashi of the International Institute for Integrative Sleep Medicine at the University of Tsukuba and colleagues have discovered the identity of the neurons that control REM sleep. “We found a brain region that controls REM sleep, and we hope to discover drugs that affect the activity of this area,” Hayashi says. “This should lead to an increase in REM sleep and, hence, improve sleep quality.”

Hayashi’s colleague, Shigeyoshi Itohara, of the RIKEN Brain Science Institute says there will be ethical concerns to take into account. “However,” he says, “if our understanding reaches a certain level, we might be able to create a novel way to manipulate sleep in humans.”