Randi Hutter Epstein M.D.

Birth, Babies, and Beyond

Here's What a Bad Night's Sleep Really Does to Your Brain

New research explains sleep deprivation.

Posted Sep 12, 2016

Source: (Image by Randi Hutter Epstein): My Sleep Deprived Twins, Joey & Martha, circa 1997

I’m probably the queen of preaching the importance of a good night’s sleep because I function so much better when I get the amount I need. But I rarely practice what I preach. There’s just too much to do. There’s just one last thing I need to read, or to see, and despite the lack of memory and the crankiness and all the other stuff that comes with a lack of sleep, somehow I fool myself into believing that staying up a little later and getting up a little earlier will help me accomplish more. And yes, I tell my children just the opposite.

The odd thing about sleep is that we know what happens when we don’t get enough but we really don’t know the biological basis. Now, a new study from researchers at the University of Pennsylvania and the University of Groningen in the Netherlands found that in mice, sleep deprivation screws up connections in the hippocampus. The hippocampus is a C-shaped organ deep in the brain associated with memory and spacial relations. So a gridlock in the way messages is likely to distort memory. That deprivation could be why when I’m really tired, I put down my house keys and then for the life of me, can’t remember where they are. Or maybe this scientific evidence is just the proof I need to convince my kids to get a good night sleep before they have an exam. And for the record, no matter how much sleep I get, I have really lousy spacial-relation issue which makes parallel parking nearly impossible.

But while the potentially alarming news from the study published in the journal eLife--that lacking sleep shrinks a portion of the hippocampus--there was a bright side. A few good nights of sleep  restore function and pumps up the hippocampus to its original size.

Sleep, perhaps, is just as elusive as the hippocampus has been. For years doctors had no ideas what it did. In the late 1950s, investigators discovered its connection to memory. That’s because surgeons removed the hippocampus of a young man, hoping to cure his severe epilepsy. The surgery apparently lessened his seizures, but also cut off his short term memory. He lived, as one of his biographers wrote, in the permanent present tense. (The story of H.M., the patient, has been retold in a recent off-broadway play, Incognito and two recent books, one by a scientist and the other by the grandson of the neurosurgeon.)

In any event, until recently we knew the hippocampus was important for memory but the sleep connection is new. The really puzzling thing—or perhaps the most fascinating of all—is that while we are piecing together the impact of sleep deprivation, we really don’t understand the basic biology of sleep itself. What is going on during a good night’s sleep?

Dr. John W. Winkelman, medical director of the Sleep Health Center, Brigham & Women’s Hospital in Brighton, Mass., once put it this way to me in an article I wrote for the New York Times: “Sleep is not the absence of wake. Your brain is active all night long, more active in REM sleep than when you’re awake. Glucose utilization is very high. People think wake is the room with the lights on and sleep is darkness, but in the darkness a lot is going on.”

This study may be just the sleep aid I need. I’ve grown deaf to even my own nagging about the importance of a good night’s sleep. (I know my kids certainly have.) But reading about how losing sleep is impacting a brain structure—affecting the chemical signals—may be just the sort of impetus to get me to turn off the computer, the T.V., shut the book, calm down or do whatever it takes to keep my hippocampus functioning the way it’s supposed to.

For pointers about getting a good night sleep, click here for New York Times's science writer, Roni Rabin’s advice

For further reading (and a fun read) about sleep, here’s a link to David Randall’s Adventures in Dreamland.