CLOCK and Cognitive impairment: Previously we showed that following MPTP‐induced nigrostriatal DA lesion, environmental cues mask the failure of the intact SCN to drive striatal clock genes and DA functions that control rest‐wake locomotor rhythms.[35] This raises the possibility of complex interactions between circadian rhythms and cognitive recovery, given the role of circadian dysfunction on cognitive impairments.[84] Here, the partial recovery of circadian rhythms in the presence of environmental timing cues (Figure 3A), could reflect incomplete restoration of DA function.