(Neuron 90, 724–739; May 18, 2016) We thank one of the readers for bringing to light that in several figures of the original publication, we used statistical tests without multiple comparisons correction. We have now applied the more appropriate one- or two-way ANOVA with post hoc Tukey tests or the Student's t test with Bonferroni multiple comparisons correction. The corrected analyses apply to the quantifications in Figures 1C, 2B, 2C, 2D, 2H, 3B, 3C, 3F, 3H, 4G, 4I, 4J, 5C, 5D, 6B, 6C, 7B, 7D, S2D, S3B, S3D, S4C, and S5C. All significance levels based on the new p values are reported in the corrected figures and the statistical tests used are reported in the corresponding figure legends and in the experimental procedures section online. Changes in the significance levels were made to Figures 2B, 2D, 2H, 3B, 3F, 4G, 4I, 4J, 5C, 5D, 6B, 7B, 7D, S2D, and S3B. All comparisons that were considered statistically significant remain significant at a p < 0.05 value, except for one case in Figure S2D. These modifications do not change any of the conclusions of our paper. The authors regret the error.