The main character of Haruki Murakami's brilliant and terrifying short story "Sleep" is a perfectly normal middle-class woman living in Tokyo. Her husband is a dentist, and they've got a lively, cheerful five-year-old son. Everything about her life is so ordinary that it's hard even to describe.
Then, in one instant, all that changes.
One night, she awakens -- or thinks she has -- to a terrifying vision that even afterward, she's not certain was real or a hallucination during sleep paralysis. A dark shape is huddled by the foot of her bed, and unfolds itself to reveal the figure of an elderly man, dressed in black, staring at her with an undisguised malevolence. She attempts to scream, and can't. After a moment, she forces herself to close her eyes, and when she opens them, the man is gone. She's drenched with sweat, so she gets up, showers, pours herself a brandy, and waits for morning.
But after that moment, she is completely unable to go to sleep. Ever.
The remainder of the story could be a teaching text in a fiction writing course lesson about how to create a believable Unreliable Narrator. She returns to her ordinary life, but everything starts seeming... off. Some senses are amplified, others dulled into nonexistence. Everyday objects appear surreal, as if they've changed subtly, but she can't quite tell how. One evening, she watches her husband as he's sleeping, and realizes that his face suddenly looks ugly to her. She takes to going out driving at night (once her husband and son are asleep) and meets people who may or may not be real. Her progressive slide into insanity reaches its apogee in the wee hours of one night, after seventeen days with no sleep, when she drives farther than she has ever driven, and ends up in an empty parking lot overlooking the ocean. Dark figures raise themselves on either side of her little car, grab it by the handles, and begin to rock it back and forth, harder and harder. She's thrown around by the motion, slamming against the door and steering wheel, and her last panicked thought is, "It's going to flip over, and there's nothing I can do to stop it."
An apt, if disturbing, summation of what is happening to her mind.
Sleep is an absolutely critical part of human health, but even after decades of research, it is unclear why. Just about every animal studied sleeps, and many of them seem to dream -- or at least undergo REM sleep -- the same as we do. (I know my dogs do; both of them bark and twitch in their sleep, and our sweet, gentle little dog Rosie sometimes growls as if she was the biggest meanest Rottweiler on the planet.)
Now, a team at the Binzhou Medical University's Shandong Technology Innovation Center has found one reason why sleep is so critical. Sleep-deprived mice stop producing a protein called pleiotrophin, which apparently has a protective effect on the cells of the hippocampus. Reduced pleiotrophin levels lead to cell death -- impairing both memory and spatial awareness. Pleiotrophin decline has also been implicated in neurodegenerative diseases like Alzheimer's.
What's unclear, though, is what direction the causation points. Does the decline in pleiotrophin from sleeplessness cause the neurodegeneration, or does the neurodegeneration lead to insomnia and a drop in pleiotrophin levels? The current research suggests the former, as the mice in the study had been genetically engineered to experience sleep disturbances, and the pleiotrophin loss seems to have followed as a consequence of the sleep deprivation. Then, the question is, if pleiotrophin decline does trigger neurodegeneration, could the damage from Alzheimer's be prevented by increasing the production of the protein?
Uncertain at this point, but it's intriguing to find one piece of a puzzle that has intrigued us for centuries. It seems fitting to end this musing on the power of sleep with the famous quote from Macbeth:
Methought I heard a voice cry ‘Sleep no more!
Macbeth does murder sleep,’ the innocent sleep,
Sleep that knits up the ravell’d sleave of care,
The death of each day’s life, sore labour’s bath,
Balm of hurt minds, great nature’s second course,
Chief nourisher in life’s feast.