Biological Basis for Less Sleep with Age
a dataset of almost 1,000 subjects (mean age at death 89.2 years; 71% female; 12 with Alzheimer’s disease) enrolled in the Rush Memory and Aging Project. Of these study participants, the team examined 45 brains, based on whether or not the ventrolateral preoptic nucleus was still intact. The investigators found that the fewer of these neurons one had, the more sleep fragmentation the person experienced in the last year of life. Brains with the largest amount of neurons (over 6,000) belonged to people with longer, uninterrupted sleep. The researchers also revealed that the link between fewer neurons and less sleep was even more pronounced in people who had died with Alzheimer’s disease. Reporting that: “These data are consistent with the intermediate nucleus being the human homologue of the ventrolateral preoptic nucleus,” the study authors submit that their findings: “demonstrate that a paucity of galanin-immunoreactive intermediate nucleus neurons is accompanied by sleep fragmentation in older adults with and without Alzheimer’s disease.”