Know an older adult who has trouble sleeping through the night but dozes off every afternoon? Most likely you do, and now researchers have some clues as to why the brain's sleeping clock seems to change with age.

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In a study published today in the Journal of Neuroscience, research shows that changes occurring in individual brain cells may play a greater role in changing sleep cycles than previously thought. Before this study, changes were attributed to weakened brain network activity in the suprachiasmatic nucleus (SCN), an area of the brain responsible for setting sleep-wake cycles.

“In fact, the changes at the single-cell level were more severe than the changes at the network level,” said Johanna Meijer, PhD, at the Leiden University Medical Center in the Netherlands, who directed the study.

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What does this mean for the elderly? The research may make it easier to find treatments that would allow older adults to maintain a more regular sleep cycle.

“This work provides a new target for potential therapeutic interventions that can mitigate the age-related decline in the sleep-wake cycle,” said Christopher Colwell, PhD, an expert in circadian clock function at the University of California, Los Angeles, who was not involved in the study.

The researchers found age-related reductions of certain potassium currents that work with the rhythmic firing of neurons; those currents can be manipulated with drugs.

The research, which was done on older animals, was particularly challenging because of the age of the animals and the small size of the SCN neurons. But the electrophysiological recordings the researchers made showed that some of the membrane properties of the neurons lacked day-night rhythms.

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