The SPM multiple regression analysis was used to analyze the influence of the degree of selective attention to babies on brain activation. For this, we used the mean Delta RT of all baby conditions from each subject and correlated them with the individual activation in the contrast of “baby vs. adult target”, separately for OT- and for placebo-treated participants. We found increased activation in the right putamen of OT-treated women (MNI-coordinates [t-value; pFWEcorr] 30, −1, 13 [5.65; 0.052]; Fig. 2a) that was positively related to selective attention to babies, but barely missed the FWE-corrected threshold in the whole-brain analysis. Yet, when extracting the parameter estimates from the right putamen, a significant positive correlation with selective attention to babies emerged (Fig. 2a). We also found a positive correlation with activation in the left putamen at the statistical threshold of p < 0.001, uncorrected (MNI-coordinates [t-value] −30, 14, 10 [4.85]; Fig. 2a). In the placebo group, two homologous clusters emerged in the posterior temporal cortex of which one survived the FWE correction on cluster level and one barely missed the statistical threshold (MNI-coordinates [t-value; pFWEcorr] 48, −22, −2 [5.69; 0.067]; MNI-coordinates [t-value; pFWEcorr] −66, −49, −2 [4.99; < 0.001]).Figure 2Degree of selective attention to babies for OT treated participants (in blue) or placebo treated participants (in red) with high or low T concentrations. (a) Activation in the left and the right putamen for baby relative to adult targets positively correlated with selective attention to babies after OT treatment (N = 29). Parameter estimates from local activation maxima (L:–21 14–11; R: 30–1 13; spheres with 6 mm radius) for the right and the left putamen are also displayed for illustration purposes. (b) Positive correlation of activation in the left and right putamen with selective attention to babies for OT treated women with high endogenous T concentrations (N = 16). (c) OT treated women with low endogenous T concentrations (N = 13) did not show activation of the putamen in relation to the relative RTs (i.e., selective attention to babies).