or SD(t) = S(t)onset − S(t)offset. Phase lock duration (LD) was defined as the interval of time between the end of a significant phase shift (i.e., peak of the 2nd derivative) and the beginning of a subsequent significant phase shift, i.e., marked by the peak of the 2nd derivative and the presence of a peak in the 1st derivative or LD(t) = S(t)offset − S(t)onset. In summary, two measures of phase dynamics were computed: (1) Phase shift duration (ms) (SD) and, (2) Phase lock duration (ms) (LD). Given the range of epoch sizes from 58 s to 2 min the range of PRs per subject was 66 to 457. Figure 1 shows an example of the computation of PR metrics in a single subject.
