Figure 2.

Distribution of morphometric characters in SN pars compacta depending on age. A) Proportion of neurons with decreased TH-immunoreactivity. B) Proportion of TH-immunonegative neurons. C) Amount of eNM per sq mm; continuous variables are presented as means and standard deviations (SD); differences between age groups were assessed using the unpaired Mann-Whitney test; black dots are outliers. D-F) Tyrosine hydroxylase immunostaining counterstained with hematoxylin. D) 25-year-old men; most neurons in human SN pars compacta are intensely TH-immunoreactive, intracellular NM accumulations are absent. E) 62-year-old women; most neurons in human SN pars compacta are moderate/weak TH-immunoreactive; some of neurons are TH-immunonegative F) 74- year-old women; eNM (arrowhead) is found in large amount. Scale bar: 20 μm.