News for hackers. Stuff that matters.

A comment on Brains Sweep Themselves Clean of Toxins During Sleep (2013). Parent comment

Re:Brains Sweep Themselves Clean of Toxins During Sleep (2013) by eloff on Friday August 14, 2015 @05:20PM (#10063016)
He's not talking about the brain conserving energy (the brain doesn't use that much energy anyway) but rather the organism as a whole by not performing other physical activity (e.g. an early human looking for food during the night when the African predators are active.)
[ Parent | on HN ]
Re:Brains Sweep Themselves Clean of Toxins During Sleep (2013) by AnimalMuppet on Friday August 14, 2015 @05:28PM (#10063046)
Well, IIRC the brain receives 25% of the body's blood flow. I think that means it's using a lot of energy (but I'm not a doctor, or a physiologist, or a biologist...)
[ Parent | on HN ]
Re:Brains Sweep Themselves Clean of Toxins During Sleep (2013) by bronson on Friday August 14, 2015 @05:59PM (#10063234)
I think that's true. Here's more support for the idea that the brain actually uses quite a lot of energy:

"Although the average adult human brain weighs about 1.4 kilograms, only 2 percent of total body weight, it demands 20 percent of our resting metabolic rate (RMR)β€”the total amount of energy our bodies expend in one very lazy day of no activity."

http://www.scientificamerican.com/article/thinking-hard-calo...

[ Parent | on HN ]
Re:Brains Sweep Themselves Clean of Toxins During Sleep (2013) by redcalx on Friday August 14, 2015 @05:45PM (#10063142)
The figure I've seen is 20%. If you burn about 2000 calories a day that works out at about 97 watts on average. 20% of that is about 19 watts. Bit more detail here:

http://heliosphan.org/bodyfatenergy.html

[ Parent | on HN ]
Re:Brains Sweep Themselves Clean of Toxins During Sleep (2013) by XorNot on Saturday August 15, 2015 @05:27AM (#10064835)
Which is still insanely low if you think about it's capabilities compared to the i7 sitting next to my legs, eating 100+ W right now.
[ Parent | on HN ]
Re:Brains Sweep Themselves Clean of Toxins During Sleep (2013) by redcalx on Saturday August 15, 2015 @12:27PM (#10065810)
Despite all of the progress in integrated circuits, the best we have is still nowhere near theoretical limits for computation per unit energy or unit space.
[ Parent | on HN ]