Nat. Neurosci. 15, 988–997 (2012); published online 10 June 2012; corrected after print 23 November 2015

In the version of this article initially published, Figure 7h presented data from rat 2 but the corresponding legend gave statistics for rat 1. The legend originally read, “Density of gold particles labeling the Cav2.1 subunit within presynaptic active zones (mean ± s.d. = 395.8 ± 154.8 gold μm−2, n = 34 in rat 1) and in the surrounding extrasynaptic axonal plasma membrane (mean ± s.d. = 1.6 ± 2.4 gold μm−2, n = 32 in rat 1) in comparison with the background labeling calculated on E-face plasma membranes (mean ± s.d. = 0.6 ± 2.3 gold μm−2, n = 39; Psynaptic < 0.01, Pextrasynaptic = 0.73).” It has been changed to give the statistics for rat 2: “Density of gold particles labeling the Cav2.1 subunit within presynaptic active zones (mean ± s.d. = 293.8 ± 122 gold μm−2, n = 49 in rat 2) and in the surrounding extrasynaptic axonal plasma membrane (mean ± s.d. = 2.8 ± 4.0 gold μm−2, n = 49 in rat 2) in comparison with the background labeling calculated on E-face plasma membranes (mean ± s.d. = 0.33 ± 1.2 gold μm−2, n = 57; Psynaptic < 0.01, Pextrasynaptic = 0.06).” The error has been corrected in the HTML and PDF versions of the article.