February 4th, 2017| Topic: RaMbLeS | 0


Why do we sleep? To rejuvenate our energy stores? To clear the brain, kinda like a soft reboot? Just an opportunity to get over the stresses and strains of daily life?

Well, we have a better idea now.

In couple of studies published the other day in Science, scientists from the University of Wisconsin-Madison, UCSD, and the Università Politecnica delle Marche, in Ancona, Italy, in one group, and researchers from Johns Hopkins in another, give us another hint: We sleep to forget!

Serial scanning 3-D electron microscopy of mice brains suggest that synapses—those connections between brain cells—grow strong and large during daytime hours with repeated activation, and then they shrink by nearly twenty percent as they sleep: the Synaptic Homeostasis Hypothesis (or SHY), as the researchers have named it.

According to SHY, the daytime growth of synapses needs to be pared down to avoid “saturation” and the obliteration of memory and the attenuation of signaling. Free from the conscious world, sleep enables those connections to be renormalized, and facilitate those brains to remain plastic and ready to learn new things the next day.

And such scaling occurred in eighty percent of the synapses, sparing only the largest ones, perhaps to retain the most stable memories.

Said one of the authors, Chiara Cirelli:

This shows, in unequivocal ultrastructural terms, that the balance of synaptic size and strength is upset by wake and restored by sleep. It is remarkable that the vast majority of synapses in the cortex undergo such a large change in size over just a few hours of wake and sleep. Extrapolating from mice to humans, our findings mean that every night trillions of synapses in our cortex could get slimmer by nearly 20 percent.”

Smart forgetfulness to get rid of the chaff!

And apparently, all of that trimming is accomplished by a protein called Homer1a, found 250 percent more in synapses of sleeping mice than in those of awake mice. Mice genetically engineered to not make Homer1a were found to be rather confused the next day. Those animals with normal Homer1a functioned alertly upon waking.

Said Graham Diering, another author:

This demonstrates why ‘sleeping on it’ can actually clarify your ideas. The bottom line is that sleep is not really downtime for the brain. It has important work to do then, and we in the developed world are shortchanging ourselves by skimping on it.”

Sleep to be smart!

But Christians knew that all along—well, at least about the importance of sleep.

When you lie down, you will not be afraid;
When you lie down, your sleep will be sweet.
Proverbs 3:24

In peace I will both lie down and sleep,
For You alone, O LORD, make me to dwell in safety.
Psalm 4:8

The fear of the LORD leads to life,
So that one may sleep satisfied, untouched by evil.
Proverbs 19:23

Indeed, it is futile to do otherwise, to stay up and work, work, work …

It is vain for you to rise up early, To retire late,
To eat the bread of painful labors;
For He gives to His beloved even in his sleep.
Psalm 127:2

Besides, God, our keeper, does not sleep, having no need of Homer or synapse …

My help comes from the LORD, Who made heaven and earth.
He will not allow your foot to slip; He who keeps you will not slumber.
Behold, He who keeps Israel Will neither slumber nor sleep.
Psalm 121:2–4

And he will sustain us, too.

I lay down and slept; I awoke, for the LORD sustains me.
Psalm 3:5

Sleep on!

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