From REAMDE, by Neal Stephenson, published 2011 :
“… The brain, as far as Richard could determine, from haphazard skimming of whatever came up on Google, was sort of like the electrical system of Mogadishu. A whole lot was going on in Mogadishu that required copper wire for conveyance of power and information. But there was only so much power to go around. And so, what wasn’t being actively used, tended to get pulled down by militias and taken cross town to beef up some power hungry warlord’s private improvised power network. As with copper in Mogadishu, so with neurons in the brain. The brains of people who did unbelievably boring shit for a living show dark patches in the zones responsible for job related processes, since all these almost never exercised neurons got pulled down and trucked somewhere else and used to beef up the circuits used to keep track of NCAA tournament brackets and celebrity makeovers.”