Furthermore, circadian disruptions have also been found in rodent PD models: mice overexpressing α-synuclein show fragmented or reduced circadian locomotor activity accompanied by reduced firing of their clock neurons, while the MitoPark mouse shows a progressive loss of clock neurons accompanied by profound disruptions to locomotor rhythms under constant conditions (Fifel and Cooper, 2014, Kudo et al., 2011, Willison et al., 2013). This evidence concerns the gene CLOCK and Parkinson disease.