Normal people do dream when they sleep, usually a couple of times. And if others claim they don't, they actually just don't remember that they have. This has been true as supported by previous studies until researchers from the University of California-Berkeley found a way to possibly turn dreams on or off.
The team led by Yang Dan, a UC-Berkeley professor of molecular and cell biology, demonstrated how activating certain neurons in the medulla can lead to rapid eye movement (REM) sleep in mice. REM sleep is the dream state that usually covers 25 percent of mammal's sleep cycle, normally occurring around an hour and a half after falling asleep, Medical News Today says.
In the press release, Dan said that most people think that medulla is involved in paralyzing the skeletal muscles during REM sleep - so they do not act out the dreams they envision. However, the team wanted to understand if these neurons - called GABAergic neurons - aside from those found in other regions (i.e. brainstem and hypothalamus) are what bring mammals to come into REM sleep.
To test this, genetically engineered mice were used as subjects. The team utilized the technique called optogenetics that made use of laser light from an inserted optical fiber to activate the GABAergic neurons in these mice. Deactivation of these neurons, on the other hand, was done through inserting an inhibitory ion pump.
Their findings say that if GABAergic neurons are activated, a sleeping mouse enters REM sleep in just a matter of seconds - as observed in about 94 percent of all mice in the study. Deactivating them, on the other hand, either reduced or completely prevented them from coming to that state. However, if the activation was made while the models were awake, it just caused the mice to eat more, which indicated a need for pleasure.
Meanwhile, while other researches proposed that noradrenergic neurons - neurons that signal the production of adrenaline when people are alert - are inactive when people eat or relax, it can be said that GABAergic neurons play the opposite. In extreme cases when noradrenergic neurons are switched off, GABAergic neurons in the medulla are turned on.
With this study, researchers believe that being able to turn dreaming on or off (even just in mice) can potentially lead to treatments that would cure people with other psychological and neurological disorders.
The study appears in the journal Nature.