Maybe Sleep Is Really For the Birds

Today’s New York Times Science section is all about a topic—sleep—of more than a little interest to parents of autistic children (although some, or many of us and our children do not get as much of it as we might wish for). My son Charlie started to sleep through the night when he was about 3 months old and—once he was asleep—nothing, nothing, could wake him. He stopped napping when he was about a year and a half (to the consternation and puzzlement of his daycare teachers and of me). While he often tossed and turned for awhile before sleeping, he always did sleep by a reasonable hour until he was about 7 years old: That was when Charlie began occasionally, and then more and more frequently, to fall asleep at 11pm, midnight, 1.30am……About a year ago, we started to give Charlie melatonin every night; we also made a lot of efforts to establish a clear and consistent bedtime routine for Charlie (this book—accurately titled Sleep Better!—helped).

The topics of the articles in the New York Times section highlight the efforts that we all go to do to help our kids (and ourselves) get maybe 20 winks: There is one on co-sleeping; another on sleep drugs; another on the effects of too little sleep (that sounds familiar). An article about bird sleep suggests that sleep is not the same for all us.

Humans need both REM sleep and slow-wave sleep, which is free of dreams and in which the neurons “fire more slowly than in REM sleep, from 40 to 400 times a second.”

Several experiments suggest that slow-wave sleep, in particular, has a crucial role in human well-being. As neurons fire in synchrony, their connections change, consolidating the memories formed in the previous day. One sign of the importance of slow-wave sleep is that if people do not have enough of it, they catch up when they can, producing stronger waves.

“If you pull an all-nighter,” Dr. Benca said, “the next night your slow waves will be much larger.”

Other mammals experience REM sleep and slow-wave sleep, as well, indicating that humanlike sleep patterns existed early in the history of mammals. But beyond mammals, scientists have had a hard time finding humanlike sleep patterns. So far, they have been seen just in birds. The fact that the closest relatives of birds, like alligators and turtles, do not have our kind of REM sleep and slow-wave sleep suggests that birds, or their dinosaur ancestors, evolved humanlike sleep independently.

I’ll have to tell that to my students when they come to class with heavy eyelids after an all-nighter: If humans do not have enough slow-wave sleep, they have to catch up on it, and humans normally need slow-wave sleep in hours. Birds, though, may need only a few minutes or even seconds:

“You and I can’t sleep in 10-second bouts,” Dr. [Ruth M.] Benca [of the University of Wisconsin] said.

Dr. [Niels] Rattenborg [of the Max Planck Institute of Ornithology in Germany] has found that birds can also keep one side of their brain awake while the other sleeps. He suspects that the awake half can keep a lookout for predators while the other half sleeps.

Dr. Benca suspects that birds may be able to make smaller parts of their brains go to sleep or wake up.

“Maybe,” she said, “we need to get away from thinking of sleep as something you have to do for so many minutes, and if the whole brain isn’t doing something that looks like sleep, then sleep isn’t happening. I think their brains are doing something else.”

Maybe we ought to talk about taking pigeon naps instead: Imagine if we could sleep with only one half of our brain while the other half remained awake—then I could sleep and still keep track of Charlie’s whereabouts……….thank goodness for melatonin.

Photo courtesy of flappingwings via Flickr.