Autopsy studies have revealed a substantial neuronal loss in the SCN in the brains of individuals with AD, which correlates with a reduction in the amplitude of motor activity rhythms observed before death.59 Furthermore, while clock gene expression persists in multiple brain regions of individuals with AD, the crucial synchronization of these rhythmic oscillators, both within and between regions, is profoundly disrupted.60 This loss of coordination may contribute to the cognitive and behavioral symptoms observed in AD. Here, CLOCK is linked to Alzheimer disease.