Scientists identify reset button for circadian clock

Scientists have found the new reset button for our circadian clock, which could open lot of treatment options for seasonal affective disorder, adverse health effects of working the night shift, or even cure jet lag.

Douglas McMahon at Vanderbilt University who directed the study said that they found they could change an animal's sleep/wake rhythms by artificially stimulating the neurons in the master biological clock, which is located in an area of the brain called the suprachiasmatic nucleus (SCN), with a laser and an optical fiber.

The study was done using mice. Neuroscientists have found that mice possess a biological clock nearly identical to that of humans with the exception that it is tuned for a nocturnal lifestyle.

The researchers used a new technique called optogenetics to manipulate the firing rate of the SCN neurons. The technique inserts genes that express optically sensitive proteins into target cells in order to make the cells respond to light.

The project involved genetically engineering two strains of mice. The neurons in the brain of one strain contained an optically sensitive protein that triggers neuronal activity when exposed to light. The neurons in the brain of the other had a similar protein that suppressed neuronal activity when exposed to light.

The researchers added that the exact approach wasn't ready for human use yet, but there was progress toward eventually using optogenetics as therapy.

The finding is reported in the journal Nature Neuroscience.