Nature 461, 636–639 (2009)

In Figure 2a of this Letter, in the key, the green line was inadvertently labelled ‘SMN’ instead of ‘CCRB’. Also, in Figure 2c, the y-axis label should be ‘Recurrence interval (d)’ and not ‘Recurrence index (d)’. The correct figure is shown below.

figure 1

Figure 1