Sleep is a brain-repair mechanism, new study proves

Scientists Lior Appelbaum and David Zada in Israel publish new proof that sleep serves to help our brains repair damage.

Their study, published in the journal Nature, used genetically engineering transparent zebrafish with colorful chemical tags attached to chromosomes in their neurons, and found that chromosomes constantly change shape to repair DNA damage, but move twice as much during sleep as when awake.

"I think this is one of the key reasons we need to sleep," said Lior Appelbaum from Bar-Ilan University in Israel. "An offline period gives us time to clean up everything for the next day, to give us a fresh start before we are busy with wakefulness again."

From The Guardian:

Appelbaum said that chromosomes are constantly changing shape to allow the cells' natural repair mechanisms to mend DNA damage at different points. When awake, the repair work cannot keep up with the rate at which damage builds up, but in the calm hours of sleep, the repair mechanisms have a chance to get on top of the job.

"It's surprising, because the brain goes into a rest state, but the chromosomes move about twice as much during sleep," Appelbaum said. "There is repair going on in the day, but sleep allows you to catch up."

The process is akin to local councils patching up potholes at night when the traffic has eased.

"I propose that, when we are very tired, neurons accumulate so much damage that they signal the whole brain that we have to go to sleep to fix the damage and avoid going into an unsafe zone," he added.

Next, they plan to replicate the study in mice.

Source: Sleep increases chromosome dynamics to enable reduction of accumulating DNA damage in single neurons

[via bullets]