Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Tuesday, March 12, 2019

A consummation devoutly to be wished

Like a lot of people, I'm struggling right now against sleep loss because of the silly switch from Standard to Daylight Savings Time, a switch I've heard compared to "cutting the top off a blanket and sewing the piece on the bottom to make it longer."

Don't get me wrong, I like the fact that it's still light when I get home from work, but given how far north I live, that'd have happened eventually anyhow.  And seems to me that since a lot of people like having more daylight hours after work, it'd make sense just to keep it that way, and not to return to Standard Time in November, further fucking up everyone's biological clock.

I mean, I have enough trouble sleeping as it is.  I've been an insomniac since my teenager years.  I never have trouble falling asleep -- my problem is staying asleep.  I'll wake up at 1:30 in the morning with my thoughts galloping full tilt, or (more often) with a piece of some song running on a tape-loop through my head, like a couple of nights ago when my brain thought it'd be fun to sing the Wings song "Silly Love Songs" to me over and over.

I hated that song even before this, but now I really loathe it.

[Image licensed under the Creative Commons Evgeniy Isaev from Moscow, Russia, Sleeping man. (7174597014), CC BY 2.0]

In any case, it was with great interest that I read some recent research from Bar-Ilan University (Israel) that has elucidated the purpose of sleep -- something that up till now has been something of a mystery.

In "Sleep Increases Chromosome Dynamics to Enable Reduction of Accumulating DNA Damage in Single Neurons," by David Zada, Tali Lerer-Goldshtein,  Irina Bronshtein, Yuval Garini, and Lior Appelbaum, which appeared last week in Nature, the authors write:
Sleep is essential to all animals with a nervous system.  Nevertheless, the core cellular function of sleep is unknown, and there is no conserved molecular marker to define sleep across phylogeny.  Time-lapse imaging of chromosomal markers in single cells of live zebrafish revealed that sleep increases chromosome dynamics in individual neurons but not in two other cell types.  Manipulation of sleep, chromosome dynamics, neuronal activity, and DNA double-strand breaks (DSBs) showed that chromosome dynamics are low and the number of DSBs accumulates during wakefulness.  In turn, sleep increases chromosome dynamics, which are necessary to reduce the amount of DSBs.  These results establish chromosome dynamics as a potential marker to define single sleeping cells, and propose that the restorative function of sleep is nuclear maintenance.
"It's like potholes in the road," said study co-author Lior Appelbaum in an interview with Science Daily.  "Roads accumulate wear and tear, especially during daytime rush hours, and it is most convenient and efficient to fix them at night, when there is light traffic."

This repair function is critical for cellular and organismal health.  If mutations and chromosomal breaks aren't fixed, it can trigger the death of the cell -- which, in the case of neurons, can create havoc.  You have to wonder if some of the age-related degradation of memory, not to mention more acute cases of dementia, are correlated with a reduction in sleep-induced genetic repair.

"We've found a causal link between sleep, chromosome dynamics, neuronal activity, and DNA damage and repair with direct physiological relevance to the entire organism," Appelbaum said.  "Sleep gives an opportunity to reduce DNA damage accumulated in the brain during wakefulness...  Despite the risk of reduced awareness to the environment, animals -- ranging from jellyfish to zebrafish to humans -- have to sleep to allow their neurons to perform efficient DNA maintenance, and this is possibly the reason why sleep has evolved and is so conserved in the animal kingdom."

What it doesn't explain is why some of us have so damn much trouble actually doing what we're evolved to do.  Shutting my brain off so it can do some road maintenance is really appealing, but for some reason it just doesn't cooperate most nights.

Which explains why I'm so tired this morning.  But what's wrong with that, I'd like to know?  So here I go AGAAAIIIIINNNNN....


This week's Skeptophilia book recommendation is an entertaining one -- Bad Astronomy by astronomer and blogger Phil Plait.  Covering everything from Moon landing "hoax" claims to astrology, Plait takes a look at how credulity and wishful thinking have given rise to loony ideas about the universe we live in, and how those ideas simply refuse to die.

Along the way, Plait makes sure to teach some good astronomy, explaining why you can't hear sounds in space, why stars twinkle but planets don't, and how we've used indirect evidence to create a persuasive explanation for how the universe began.  His lucid style is both informative and entertaining, and although you'll sometimes laugh at how goofy the human race can be, you'll come away impressed by how much we've figured out.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

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