Importantly, we found that there was an increase of ~140% (P < 0.01, two-way ANOVA) in the density of c-Fos+ nuclei in the globus pallidus on the lesioned side in PD-D mice when compared to PD mice (Figure 7D; naïve controls: 4 ± 2; PD mice: non-lesion, 5 ± 3 and 6-OHDA-lesion, 38 ± 8; PD-D mice: non-lesion, 8 ± 7 and 6-OHDA-lesion, 92 ± 11; means ± SEM; n = 10). Here, FOS is linked to Parkinson disease.