The immune system. Metabolism. Learning and memory. Running short on sleep impairs each of these functions and processes, and now scientists say that it can affect our emotional balance, too.

A group led by Berkeley neuroscientist Matthew Walker used fMRI scans of subjects to show that a lack of sleep messes with the brain’s ability to respond to negative stimuli. The researchers kept the volunteers awake for 35 hours, showed them images that would provoke positive or negative reactions, and recorded the response in brain activity. Regions of the brain associated with emotional reactions spiked in sleep-deprived subjects, relative to the well-rested. A word to fathers with newborns: Don’t show this paper to your wife. She won’t appreciate it.—Gregory Mone

Via MindHacks