To evaluate whether the activity of wFMNs-projecting vlPAG neurons is altered following CRS or BoNT/A application, we examined the expression of c-Fos, an immediate early protein used to detect neural activity, in the vlPAG among the subgroups of naïve and CRS mice with saline or BoNT/A (10 U/kg) administration 3 weeks prior to the end of CRS. This evidence concerns the gene FOS and congenital rubella syndrome.