This was also evidenced by the fact that the percentage of reduction in the number of DA-ChAT connections in PD (54.78% reduction compared to controls) (Additional file 1: Table S4) was higher than the percentage of reduction in the density of ChAT cells (46.11% reduction in INL ChAT cells and 35.15% in GCL cells compared to controls) (Additional file 1: Table S5). Here, CHAT is linked to Parkinson disease.