Advertisement

Erratum

        Erratum to: “Dorsomedial Prefrontal Cortex Mediates the Impact of Serotonin Transporter Linked Polymorphic Region Genotype on Anticipatory Threat Reactions” by Klumpers et al. (Biol Psychiatry 2015; 78:582-589).
        The authors discovered an error in the genotype coding for 7 out of 99 participants of one of the two samples (sample 1). Genotype coding for sample 2 was not affected. Re-analyses correcting for this error marginally changed the statistical values of the tests but did not change whether or not statistical thresholds were reached. Therefore, interpretations and conclusions reported in the article remain unaffected. The required corrections and a justification of their implication to the conclusions, along with an updated figure, are as follows.
        The corrected genotype frequency distribution in sample 1 is 10 S/S, 52 S/L, and 37 L/L (originally reported in Table 1 as 16 S/S, 53 S/L, 30 L/L). The updated genotype distribution is still within Hardy-Weinberg equilibrium (p = .18) and there remain no differences in age, sex distribution, or trait anxiety between genotype groups (p’s > .3) (originally reported in paragraph 1 of the Results, page 585).
        Also, other previously reported results remain intact upon re-analysis. In sample 1, the 5-HTTLPR (S-carriers, LL) x threat (threat, safe) interaction on psychophysiological threat reactions remains near trend level at p = .12 (p was .13, as originally reported in Results, column 2, page 585). Critically, across sample 1 and sample 2, a post-hoc omnibus repeated measures analysis with experiment as factor again did yield a p value < .05 (5-HTTLPR x threat F1,163 = 5.13, p = .025 (p was .028, as originally reported in Results, column 2, page 585).
        Most importantly, the imaging results that had shown a mediating role for the dmPFC in genotype-driven potentiation of psychophysiological threat reactions also remained intact. The updated mediation analysis diagram that summarizes all effects can be found in the revised version of Figure 4, included here. As depicted, all the previously reported effects remain significant with only minor changes in path estimates and associated p-values. The legend remains unchanged.
        Figure 4.
        Figure 4Activation in the dorsomedial prefrontal cortex (dmPFC) mediated the relationship between serotonin transporter linked polymorphic region (5-HTTLPR) genotype and psychophysiological responses to threat in both sample 1 (left) and sample 2 (right – not changed). Genotype at 5-HTTLPR predicts threat-related activity in the dmPFC (path a). Activity in the dmPFC mediator region predicts the outcome, i.e., skin conductance response (SCR) and fear-potentiated startle (FPS) (path b). The direct connection from 5-HTTLPR to psychophysiological responses controlled for the mediation effect is provided at the bottom (path c׳) and the total effect is in square parenthesis [path c]. The lines are labeled with path coefficients, and standard errors are shown in parentheses. Asterisks indicate p values (two-tailed).
        In detail, the revised mediation analyses on sample 1 again confirmed that S-carriers showed increased dmPFC activity to threat (path a: t98 = 2.90, p = .003 (was < .001)), and that greater dmPFC activity predicted greater psychophysiological reactions (path b: t97 = 3.25, p < .001 (was < .001)), and again found dmPFC activity to significantly mediate 5-HTTLPR effects on psychophysiological reactions (path ab: t98 = 2.00, p = .009 (was .009)) just as in sample 2.
        Thus, the conclusion of a mediating role for the dmPFC in the effect of 5-HTT genotype on somatic anticipatory threat reactions remains intact after the authors corrected the results for this genotype coding error.

        Linked Article