The reduction of PVN oxytocin‐immunoreactive neurons has been observed in postmortem PD patients.[16] In the MPTP‐induced PD mouse model, we also observed reductions of PVN oxytocin‐positive neurons, PVN Oxt mRNA level, and plasma oxytocin level (Figure 1), which may be induced by the decrease of oxytocin neuronal activity. Here, OXT is linked to Parkinson disease.