New research suggests that light (and a little genetic modification) may be the answer to a better night’s sleep.
Researchers from MIT and Harvard Medical school have found a way to induce REM sleep in mice using new technology called optogenetics. REM, or rapid eye movement, sleep is the stage in the sleep cycle stage most associated with dreaming and the processing of information that leads to learning. During a night’s sleep, a person goes through several sleep stages that include REM and non-REM episodes. The researchers were able to induce REM sleep in mice by inserting a special light-sensitive protein into brain cells. These proteins are found in algae and because they are light sensitive, once they are inserted into brain cells the researchers can activate them using certain frequencies of light. Light is shined through fiber optic cables, similar to those in the image below, attached to the surface of the skull. This insertion of light-sensitive proteins to make cells light-sensitive is called optogenetics.
Neurons called cholinergic neurons, located in the brainstem, have previously been found to be active during REM sleep, but it has not been known whether activation of these cells causes REM sleep. Adding the light-sensitive protein into the mice genome allowed researchers to control the activation of these cholinergic neurons. Certain wavelengths of light (in this example, 532 nanometers) can create measurable brain responses, seen as waves.
Image Source: Rick Gayle Studio
Results of the study showed that activating the cholinergic neurons with blue laser light during non-REM stages of sleep increased the number of REM sleep events the mice had. These induced REM sleep cycles closely matched natural REM cycles. The length of the REM cycles, however, was not affected, suggesting that the activation of cholinergic neurons are important for initiating REM sleep, but not maintaining REM sleep.
This research suggests that we are close to finding a way to artificially create a good night’s sleep, exciting news for people who suffer from insomnia and other sleep disorders. This research also shows the power of optogenetics, which allows for control of brain function at a cellular level.
Feature Image Source: Embassy Suites – San Francisco by Scott Swigart