Last night, I stayed up beyond my usual bedtime to watch my beloved (and occasionally disdained) Boston Red Sox play the Cleveland Indians in the deciding game of the American League Championship Series. To my delight, the hometown Sox were victorious and now advance to their second World Series in four years. Once the game concluded, I dove beneath the bed covers, but, as I was still tingling with a certain measure of excitement, it took me some time to dive into slumber. Less than five hours later, I was awake and groggily preparing for the workday. As this day has worn on, I have found myself increasingly cranky, despite my pleasure at the accomplishment of the Beantown bashers. Thanks to the following article from HealthDay, I now have an explanation for my sudden grumpiness:

Sleepless Nights Make for Grumpier Brains

Ever get a little testy after a bad night’s sleep? Scientists may now know why.

A new study finds that a lack of sleep causes the brain’s emotional centers to dramatically overreact to negative experiences.

A shutdown of the prefrontal lobe — a brain region that normally keeps emotions under control — is the reason for heightened emotional response in sleep-deprived people, said the researchers from Harvard Medical School and the University of California, Berkeley.

Reporting in the Oct. 23 issue of the journal Current Biology, the team said its study is the first to determine, at the neural level, why lack of sleep can lead to emotionally irrational behavior and may help improve understanding of the link between sleep disruptions and psychiatric disorders.

“This adds to the critical list of sleep’s benefits,” Matthew Walker of the University of California, Berkeley, said in a prepared statement. “Sleep appears to restore our emotional brain circuits, and, in doing so, prepares us for the next day’s challenges and social interactions. Most importantly, this study demonstrates the dangers of not sleeping enough. Sleep deprivation fractures the brain mechanisms that regulate key aspects of our mental health.” [full text]