FOS and in situ carcinoma: Immunofluorescence staining results (Fig. 4a) revealed that, in comparison to the mice of UAC group, the mice of CIS + UAC group had increased c-fos expression in both the Vc and TG, indicating enhanced neuronal activity, whereas the mice of 6-OHDA + UAC and SCG + UAC groups showed reduced c-fos expression in the Vc and TG, pointing to decreased neuronal activity.