dj-1β^b flies have the same amount of dopaminergic neurons as controls at 20 or 40 days old. However, at 60 days, the mutants show a higher number of dopaminergic neurons compared to controls. Dopaminergic cell clusters in PPL1, PPM1/2 and PPL2 regions of the brain survive better in dj-1β^b mutants compared to other regions. However, despite the reduction in dopaminergic neuron loss, 60 day-old dj-1β^b flies display sedentary behaviour similar to wild-type flies of the same age. dj-1β^b flies, like wild-type flies, show no reduction in the amount of serotoninergic neurons between the ages of 10 and 60 days. dj-1β^b flies show resistance to paraquat. However, these flies are more sensitive to H₂O₂ than wild-type flies.