NR4A2 and Parkinson disease: Of special mention, besides its crucial role for the development, maintenance and protection of midbrain DAergic neurons, the relevance of the transcription factor Nurr1 for adult hippocampal neurogenesis in PD has been recently highlighthed, and several lines of evidence indicate that pharmacological stimulation of Nurr1 can improve behavioral deficits via an increase in hippocampal neurogenesis (Kim et al., 2015; Kim et al., 2016 and section 6.4.1).