Sleep deprivation linked to risky behavior

IVANHOE NEWSWIRE - From overworked professionals to over-extended students, everyone worries about how much sleep they're getting. A new study from Duke University has shown yet another consequence of not sleeping enough: sleep deprivation can lead to a more optimistic outlook, resulting in riskier decisions.

Using a functional MRI, scientists showed that a lack of sleep increases brain activity in the brain regions that assess positive outcomes while decreasing activity in the regions that process negative outcomes. The study also showed a link between sleep deprivation and an increased sensitivity to positive rewards (with a corresponding decreased sensitivity to negative consequences).

While it has long been established that a lack of sleep affects decision-making abilities, the Duke University study links that effect to an increase in optimism rather than impaired attention and memory function. It is also the first study to demonstrate how sleep deprivation changes the way the brain assesses economic value, changes that are independent of sleep deprivation's effects on vigilance.

Researchers tested 29 adults, setting them with economic decision-making tasks after a night of normal sleep and a night of sleep deprivation. To establish a link between sleep deprivation and neural sensitivity to rewards, participants watched as gambling outcomes were sorted as positive or negative.

"Even if someone makes very sound, risky financial decisions after a normal night of sleep, there is no guarantee that this same person will not expose you to untoward risk if sleep is deprived," Michael Chee, M.D., senior author and professor at the Neurobehavioral Disorders Program at Duke-NUS in Singapore, was quoted as saying.

"I think it's critical that society as a whole grapple with the data generated about the detrimental effects of sleep deprivation and consider whether to continue doing things the old way."

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