Act Environmentally When Peers Do So? The Effect of Friends' and Strangers' Resource Extraction on Preschool Children's Pro-Environmental Behavior.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in cognitive, affective, and sleep deficits. Daytime sleepiness, frequent nighttime awakenings, and overall poor sleep quality have long been reported in persons with AD. The development of sleep deficits prior to cognitive impairment is mirrored by the accumulation of a hyper‐phosphorylated pathological form of the protein tau (pTau) in brainstem regions prior to the development of cortical and hippocampal pathology., , , Generally, pTau burden corresponds to the severity of associated symptoms. However, the relationship between disease progression and sleep orchestration is much more complex; recent studies found a non‐linear U‐shaped relationship between cognitive impairment and sleep orchestration. As a result, how this early brainstem pathology disrupts sleep and which cell types are most relevant have yet to be fully characterized. To date, studies in rodent models of AD or other tauopathies have yielded inconsistent sleep phenotypes. Some studies show decreased non‐rapid eye movement (nREM) sleep or changes in electroencephalogram (EEG) spectra, while other groups report no changes in sleep parameters., , , , The models used in these studies have shown utility in investigating the mechanisms underlying cognitive deficits; however, the levels and effects of pTau in brain regions relevant to sleep might not share the same time course in each model; indeed, our previous work showed that changes in depressive and anxiety‐like behaviors were not apparent at each timepoint., Because the progression of tau pathology may affect various neuronal types differently, sleep disruptions might not be apparent in each model at the times tested. The dorsal raphe nucleus (DRN) is the largest of the brain's serotonin (5‐HT)‐producing nuclei and a common site of early pTau accumulation., Critically, the DRN plays a major role in both sleep‐wake orchestration and the transition between sleep stages, metrics known to be affected during the prodromal phase of AD (also known as the preclinical phase)., , We elect to use the term prodromal phase, as patients suffering from these symptoms do report clinically, though they are not diagnostically associated with AD as there remains a paucity of differential diagnostic criteria at this stage.