Some neurons exhibit differential vulnerability to oxidative damage. Cerebellar granule and hippocampal CA1 neurons are more sensitive to oxidative stress than cerebral cortical and hippocampal CA3 neurons (Wang X. et al., 2009; Wang and Michaelis, 2010). Hence, it is possible that similar differences in vulnerability to oxidative stress might exist between MN populations. However, this possibility needs to be confirmed experimentally.