Nature Reviews Neurology 11, 457–470 (2015)

In the initially published version of this article, Figure 1 had an incomplete credit line. The correct credit line reads: Redrawn from Nedergaard, M. Garbage truck of the brain. Science 340, 1529–1530 (2013). Reprinted with permission from AAAS. This error has been corrected in the HTML and PDF versions of the article.