Their research shows that individuals with a particular variation of the DRD2 gene are resilient to the effects of sleep deprivation when completing tasks that require cognitive flexibility, the ability to make appropriate decisions based on changing information.
Sleep-deprived people with two other variations of the gene tend to perform much more poorly on the same kinds of tasks, the researchers found.
The DRD2 dopamine receptor gene influences the processing of information in the striatum, a region of the brain that is known to be involved in cognitive flexibility.
When deprived of sleep, some people respond better than others. Scientists have identified genes associated with this, but they have wondered why the effects of sleep loss tend to vary widely across both individuals and cognitive tasks. For example, after a day without sleep, some people might struggle with a reaction time test but perform well on decision-making tasks, or vice versa.
In the current study, Whitney, along with colleagues John Hinson, WSU professor of psychology, and Hans Van Dongen, director of the WSU Sleep and Performance Research Center at WSU Spokane, compared how people with different variations of the DRD2 gene performed on tasks designed to test both their ability to anticipate events and their cognitive flexibility in response to changing circumstances.
Forty-nine adults participated in the study at the WSU Spokane sleep laboratory. After a 10-hour rest period, 34 participants were randomly selected to go 38 hours without sleep while the other participants were allowed to sleep normally.
Before and after the period of sleep deprivation, subjects were shown a series of letter pairings on a computer screen and told to click the left mouse button for a certain letter combination (e.g., an A followed by an X) and the right mouse button for all other letter pairs. After a while, both the sleep-deprived group and the rested group were able to identify the pattern and click correctly for various letter pairs.
Then came the tricky part: in the middle of the task, researchers told the participants to now click the left mouse button for a different letter combination. The sudden switch confounded most of the sleep-deprived participants, but those who had a particular variation of the DRD2 gene handled the switch as well as they did when well-rested.
“It is exciting to see this kind of creative research emerge from a collaboration of our cognitive neuroscientists in the College of Arts and Sciences and our medical science researchers in the Sleep and Performance Research Center,” said Daryll DeWald, dean of the college and chancellor of WSU Spokane.
Sleep deprivation’s effect on cognitive flexibility can have serious consequences, especially in high stakes, real-world situations like an emergency room or military operations where the ability to respond to changing circumstances is critical. For example, after a night without sleep, a surgeon might notice a spike in a patient’s vital signs midway through a procedure but be unable to use this information to decide on a better course of action.
The WSU research team is currently applying what they learned from their study to develop new ways to help surgeons, police officers, soldiers and other individuals who regularly deal with the effects of sleep deprivation in critical, dynamic settings cope with the loss of cognitive flexibility.
The research is in keeping with WSU’s Grand Challenges, a suite of research initiatives aimed at large societal issues. It is particularly relevant to the challenge of sustaining health and the uncompromising pursuit of healthier people and communities.