Nat. Neurosci. 20, 735–742 (2017); published online 3 April 2017; corrected online 10 April 2017; corrected after print 5 May 2017

In the version of this article initially published, the histogram in Figure 2c, center top graph, was duplicated from the panel below, and the remaining histograms accompanying the scatter plots in Figures 2c and 5c were slightly mis-scaled and misaligned relative to the scatterplots. The histograms, as well as the vertical scaling of Figure 5c, bottom right graph, have been adjusted. Also, one data point from the scatterplot in the top right panel of Figure 2c had originally been transformed from a negative value on the vertical axis to its absolute value. The errors have been corrected in the PDF and HTML versions of this article.