Can the flip of a switch send you to dreamland?
Researchers at the University of California, Berkely, inserted an optogenetic switch into a group of nerve cells in the medulla of a mouse’s brain. This allowed researchers to activate or inactivate the neurons with laser light.
When the neurons were activated, the sleeping mice entered REM sleep within seconds. REM sleep, characterized by rapid eye movements, is the dream state accompanied by activation of the cortex and total paralysis of the skeletal muscles, presumably so that we don’t act out the dreams flashing through our mind.
Inactivating the neurons reduced or even eliminated a mouse’s ability to enter REM sleep.
The discovery will not only help researchers better understand the complex control of sleep and dreaming in the brain, but will allow scientists to stop and start dreaming at will in mice in order to better learn why mammals dream.
Many psychiatric disorders are correlated with changes in REM sleep. Researchers are hoping that studying the sleep circuit might lead to new insights into these disorders, as well as neurological diseases that affect sleep, like Parkinson’s and Alzheimer’s diseases.
The researchers also found that activating these brain cells while the mice were awake had no effect on wakefulness, but did make them eat more.
