Differential vulnerability of catecholaminergic brainstem neurons in healthy aged controls. 3-D model of the brain showing location of brainstem nuclei and ΔmtDNA levels of pigmented (TH+/NM+) and non-pigmented (TH+/NM-) catecholaminergic neurons, as well as non-catecholaminergic (TH-) neurons in these nuclei. Values represent mean ± standard deviation of data collected from healthy aged controls (78.7 ± 9.0 years). Highest deletion levels are seen in pigmented neurons of the SNc (black). VTA neurons show intermediate ΔmtDNA levels (grey) and LC neurons lowest (light grey). PD pathology is deviating from this pattern, as SNc and LC show heavy degeneration whereas the VTA is relatively spared.