Successful Aging: A Neuroscientist Explores the Power and Potential of Our Lives

by Daniel J. Levitin

One of the functions of sleep is to process the most emotionally intense experiences of the previous day, to separate the facts from our feelings so that we can reach a quasi-objective view of things. The other reason for doing so is so that the emotions themselves can be entered into and stored in memory. It is of value to be able to access a memory based not just on a particular time or a particular place (which we can all do), but also on a particular emotion. All the experiences you’ve had of being humiliated, for example, can be bound together through emotional memory, in order to help you extract patterns and (hopefully) modify your future behavior. Sleep-deprived people show a 60 percent greater activation in their amygdala during waking hours than those who are not sleep-deprived. Because the amygdala is part of the brain’s fear circuit and is known to trigger aggression, anger, and rage, this finding highlights the relation between sleep deprivation and emotional regulation. When your mom told you that you were being crabby because you didn’t get enough sleep, she was probably right.