The discovery of a new “reset” button for the brain’s master biological clock could eventually lead to new treatments for conditions like seasonal affective disorder, reduce the adverse health effects of working the night shift and possibly even treat jet lag. The finding is reported in the Feb. 2 issue of the journal Nature Neuroscience.
“We found we can 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,” said Douglas McMahon, Stevenson Professor of Biological Sciences at Vanderbilt University who directed the study.
Until now, neuroscientists had thought that the firing rate of SCN neurons was strictly an output of the biological clock’s activity. They did not think altering the level of neuronal activity could affect how the clock operates. But the Vanderbilt researchers have shown that stimulating and suppressing the SCN’s neurons in a fashion that emulates their day and night activity levels can force the clock to reset.
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.
“This puts clock neurons under our control for the first time,” said doctoral student Jeff Jones, who conducted the study with fellow doctoral student Michael Tackenberg.
Via Dr. Stefan Gruenwald