Some research suggests that insomnia is a hybrid state, when the brain is neither fully asleep nor fully awake.
Now there’s new evidence for this claim. A University of Pittsburgh study in the October issue of the journal Sleep suggests that insomniacs’ inability to quiet the brain at night is linked to pockets of activity that show up in PET scans while the rest of the brain is asleep.
I was thinking about the implications of this when I went to bed last night. Strange as it may sound, I think it may actually have helped me fall asleep. More about this following news of the study:
Glucose Metabolism During Sleep and Wake
Information processing and thinking require energy. So lots of glucose gets metabolized in the brain during the daytime. Much less glucose is metabolized at night, when the brain is fairly quiet.
The Pitt researchers wanted to assess metabolic activity in the brains of people with and without insomnia to see if there were differences at night and during the daytime. PET scans can measure the rate of metabolic activity occurring in different regions of the brain and render the information in images. So the researchers screened two groups of participants—44 insomniacs and 40 good sleepers—and administered PET scans when they were sleeping and after they woke up.
Summarizing the study results, Daniel Buysse, co-author and professor of psychiatry at the University of Pittsburgh, was quoted in TribLive.com, saying, “What we found is that the people with insomnia have regions of their brain that seem to not shut off as completely when they’re asleep.”
Pitt researchers have been pursuing this line of research for over a decade now. In 2004, results of their first (smaller) neuroimaging study of insomniacs and good sleepers were published, showing similar results.
Regions of Activity and Inactivity in the New Study
Which brain regions were unusually active during sleep? Compared with images of good sleeper brains, the images of insomniacs’ brains during sleep showed significantly higher metabolic activity in 3 key regions associated with
- Memory and self-reflection
- Affect, or mood
This fits pretty neatly with the experience of insomnia, when at night the mind just doesn’t seem to be able to turn itself off. How familiar are thoughts like these: Can I meet my deadline tomorrow? It’s depressing that I handled the presentation so badly. What are they thinking about me now?
Just as interesting was the finding that these same regions of the brain were underactive in insomniacs after they woke up in the morning.
Ever have trouble hauling yourself out of bed? concentrating on your work? feeling low and out of sorts after a bad night’s sleep? Daytime symptoms of insomnia—lack of stamina, trouble thinking, moodiness—may also correspond to the level of metabolic activity occurring in various regions of the brain.
How I Fell Asleep Last Night
When the midnight train whistle sounded I was still engrossed in a novel. But I finally lay down to an internal dialog with myself as I waited to fall asleep:
How’s the spy in the novel going to get back to Viet Nam?
He’s already writing his memoirs in a 3- by 5-foot prison cell. It could get grisly. Bad choice for bedtime reading!
I forgot to read the election news.
Anything but the election! Get back to the character in the book!
I’m too hot. That’s a bad sign.
Throw off a cover, will you!
I might have trouble sleeping.
You’ll fall asleep eventually. You might be partway there.
What if parts of my brain were already asleep? What if at that moment I was experiencing exactly what the neuroimaging studies showed, with parts of my brain already sleeping and other parts resisting sleep? Could I entertain the notion that my brain was halfway released from its burden of consciousness when my mind and senses argued otherwise?
It must have been a comforting proposition. Because after that I was out.
Have you ever had the sensation of being partly awake and partly asleep? What did it feel like?