Zapping the brain to control scary dreams
Lucid dreaming Dreams in which you encounter an axe-wielding psychopath or show up at work naked could be controlled by a benign electrical current applied to the brain, say researchers.
In a study, published online in Nature Neuroscience, they say the current can induce "lucid dreaming," in which the dreamer is aware that they are dreaming and can often gain control of the ongoing plot.
The findings are the first to show that inducing brain waves of a specific frequency produces lucid dreaming.
Previous research has associated lucid dreaming during the REM (rapid-eye movement) stage of sleep with telltale electrical activity in the frontal and temporal regions.
Electroencephalograms showed that those dreams were accompanied by gamma waves.
Those brain-waves are related to executive functions such as higher-order thinking, as well as awareness of one's mental state. But they are almost unheard of in REM sleep, during which the dreamer's conscious state usually has no access to past memories or anticipated events in the future.
Until now it was not clear whether lucid dreaming was triggering gamma-band activity or whether gamma-band activity was triggering lucid dreaming.
Scientists led by psychologist Dr Ursula Voss of Goethe-University in Frankfurt, Germany, investigated whether a current with the same frequency as gamma waves in dreaming brains would encourage lucid dreaming.
In a study involving 27 volunteers, the researchers induced a current via electrodes to the frontal and temporal brain using in a technique called transcranial alternating current stimulation (tACS).
With stimulation in the lower gamma frequency band at 40 Hertz (and to a lesser extent, 25 Hertz) the volunteers reported that they were aware that they were dreaming, and were able to exercise control over the dream plot.
And the volunteers also felt as if their dream self was a third party whom they were merely observing.
Post-traumatic stress disorder
Voss does not foresee a commercial market in lucid-dreaming machines. Devices currently sold "do not work well," she says, and those that deliver electrical stimulation to the brain, like the one in her study, "should always be monitored by a physician."
But if the results hold up, the technique might help people suffering from post-traumatic stress disorder, who often have terrifying dreams in which they re-play the traumatic experience. If they can dream lucidly, they might be able to bring about a different outcome, such as turning down a different street than the one with the roadside bomb or ducking into a restaurant before the rapist attacks them.
"By learning how to control the dream and distance oneself from the dream," says Voss, PTSD patients could reduce the emotional impact and begin to recover.